# 1080p 24fps HD VOD ever?



## jediphish (Dec 4, 2005)

With recent news that DISH may do something like this, what are the chances that D* will have such an offering any time in the future? I love Blu-Ray but would also like to be able to get 24fps material from the sky as well.


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## litzdog911 (Jun 23, 2004)

"ever" is a very long time. Someday, we'll probably see full blown 3-D virtual reality with much greater than 1080p resolution. Hopefully in my lifetime


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## jediphish (Dec 4, 2005)

litzdog911 said:


> "ever" is a very long time. Someday, we'll probably see full blown 3-D virtual reality with much greater than 1080p resolution. Hopefully in my lifetime


I ask because as I contemplate venturing into the BR disc world with a purchase, I would rather have a one-box solution, e.g. D* feeding me 24fps HD movies on demand.


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## feschiver (Dec 19, 2006)

How fast is your download speed


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## Brandon428 (Mar 21, 2007)

feschiver said:


> How fast is your download speed


Anything short of ultra fast you won't be streaming 1080p I can't even stream 480i.:lol: 
All I can get out here is 1.5mb down,256kb up. I do think directv if they have enough space on their sats should offer 1080p ppv movies.


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## jediphish (Dec 4, 2005)

feschiver said:


> How fast is your download speed


6mb/sec

I watch about 2 movies per week and would not expect to watch them instantly, just would like to have access to them from D*. I thought I read somewhere that the bandwidth requirements to send 1080p 24 frames/sec is not that much greater than 1080i 60fields/sec.


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## LarryFlowers (Sep 22, 2006)

It could come to pass... when and if the demand is there. It is one thing to offer it, another entirely for it to be useful.

Face it, not a lot of people have internet connections faster than 3MB, let alone the 6 or more it would take to make this viable.


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## Brandon428 (Mar 21, 2007)

LarryFlowers said:


> It could come to pass... when and if the demand is there. It is one thing to offer it, another entirely for it to be useful.
> 
> Face it, not a lot of people have internet connections faster than 3MB, let alone the 6 or more it would take to make this viable.


I agree. The only way it would be viable is if they delivered it via satellite.


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## jediphish (Dec 4, 2005)

More and more panels are capable of displaying 1080p24fps in some proper multiple, eliminating some judder.

http://www.avsforum.com/avs-vb/showthread.php?t=997138

Not everyone has fast download speeds now but its a good bet that such DL speeds will likely increase.


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## cartrivision (Jul 25, 2007)

jediphish said:


> With recent news that DISH may do something like this, what are the chances that D* will have such an offering any time in the future? I love Blu-Ray but would also like to be able to get 24fps material from the sky as well.


For about the tenth time..... you can already get 1080p/24 video from existing DirecTV HD transmissions. 24fps source material that is transmitted in 1080i/60 has every bit of information that would be contained in a 1080p/24 transmission of the same source. A properly deinterlaced 1080i/60 transmission of 24fps source will be no different than if it had been transmitted in 1080p/24.

If you have a 120Hz refresh rate HDTV the 1080i/60 signal will be deinterlaced into 24 progressive frames per second that are then each repeated 5 times each to match the TV's 120fps frame rate, giving you exactly the same picture that you would have gotten from 1080p/24.

The same idea applies if you are watching on a 60Hz refresh rate HDTV. As long as the TV does the deinterlacing properly, there is no difference in the end result between a 1080p24 and a 1080i/60 transmission of 24fps source material.


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## DarinC (Aug 31, 2004)

Brandon428 said:


> Anything short of ultra fast you won't be streaming 1080p I can't even stream 480i.:lol:


1080p/24 takes less bandwidth than 1080i/60. Theoretically, a "fast" internet connection (6-8mb+) should be able to stream that. But what I've found with DirecTV is, their servers can't push it out that fast.


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## DarinC (Aug 31, 2004)

cartrivision said:


> If you have a 120Hz refresh rate HDTV the 1080i/60 signal will be deinterlaced into 24 progressive frames per second that are then each repeated 5 times each to match the TV's 120fps frame rate, giving you exactly the same picture that you would have gotten from 1080p/24.


1080i/60 content would have already gone through a 3/2 pulldown to get to 60hz, then simply multiplied times two to get to 120hz. It _could_ have reverse pullodwn applied to it, then processed through proper 5/5, but Faroudja has a patent on that. I don't know if any TVs are doing that. I would expect that most only do a proper 5/5 if they are fed a 24hz input. Therefore, you end up with judder.


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## davring (Jan 13, 2007)

DarinC said:


> 1080p/24 takes less bandwidth than 1080i/60. Theoretically, a "fast" internet connection (6-8mb+) should be able to stream that. But what I've found with DirecTV is, their servers can't push it out that fast.


It appears that downloads are throttled to about 2mbps, my observation of course. I have two HR's networked and with both downloading, at the same time, I still have about 2mbps of bandwidth left on my 6.0 DSL. If I run a speed test while downloading it appears to measure what is not being used at the time. If I am downloading to one HR, my reserve is almost always 4mbps. I'm sure these are not absolute measurements, but good reference anyway.


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## Tom Robertson (Nov 15, 2005)

cartrivision said:


> For about the tenth time..... you can already get 1080p/24 video from existing DirecTV HD transmissions. 24fps source material that is transmitted in 1080i/60 has every bit of information that would be contained in a 1080p/24 transmission of the same source. A properly deinterlaced 1080i/60 transmission of 24fps source will be no different than if it had been transmitted in 1080p/24.
> 
> If you have a 120Hz refresh rate HDTV the 1080i/60 signal will be deinterlaced into 24 progressive frames per second that are then each repeated 5 times each to match the TV's 120fps frame rate, giving you exactly the same picture that you would have gotten from 1080p/24.
> 
> The same idea applies if you are watching on a 60Hz refresh rate HDTV. As long as the TV does the deinterlacing properly, there is no difference in the end result between a 1080p24 and a 1080i/60 transmission of 24fps source material.


For about the second time, your statement is only true in regards to a single frame. 1080i60 frames in succession are more "data" than 1080p24 but its not the native format used in the original movie. 3:2 conversion introduces artifacts that are not there in a 1080p24 transmission.

Cheers,
Tom

BTW, why are you whining about counting?


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## RunnerFL (Jan 5, 2006)

LarryFlowers said:


> Face it, not a lot of people have internet connections faster than 3MB, let alone the 6 or more it would take to make this viable.


Not to mention a TV that would handle that resolution. At least not yet.


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## Tom Robertson (Nov 15, 2005)

Speaking of TVs, I was talking to Joe Kane of WideScreen Review (and other cool video toys) at CES in 2007. The CEA who runs the show wanted to have a dedicated internal channel on the show floor that was all 1080p content to help manufacturers showcase 1080p.

It had to be abandoned because only a third of the 1080p marketed TVs at that time really could handle all the 1080p modes, most often failing the 1080p24 mode--most important for movies. 

Cheers,
Tom


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## bonscott87 (Jan 21, 2003)

How about getting a decent selection of plain old 720p/1080i HD first? :hurah:


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## Tom Robertson (Nov 15, 2005)

I've got DIRECTV. I've got LOTS of 1080i HD to watch


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## DarinC (Aug 31, 2004)

Tom Robertson said:


> Speaking of TVs ... only a third of the 1080p marketed TVs at that time really could handle all the 1080p modes, most often failing the 1080p24 mode--most important for movies.


Yes, I'm soon to be in the market for a new one. Seems that many, even when fed a proper 24fps signal, still do 3/2 pulldown, then just multiply the result by 2!?! Just seems crazy. And it can be really difficult getting a reliable answer from the Mfg to know for sure how a particular set handles it. :nono2:


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## jediphish (Dec 4, 2005)

Tom Robertson said:


> Speaking of TVs, I was talking to Joe Kane of WideScreen Review (and other cool video toys) at CES in 2007. The CEA who runs the show wanted to have a dedicated internal channel on the show floor that was all 1080p content to help manufacturers showcase 1080p.
> 
> It had to be abandoned because only a third of the 1080p marketed TVs at that time really could handle all the 1080p modes, most often failing the 1080p24 mode--most important for movies.
> 
> ...


My 3 year old TV can handle 24 fps input and will display at 3x the rate (albeit it downscales to 768p but it does display 24 fps native frames in their proper sequence). I realize not all TVs can do this but it would seem that more will as time goes on.


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## jediphish (Dec 4, 2005)

DarinC said:


> Yes, I'm soon to be in the market for a new one. Seems that many, even when fed a proper 24fps signal, still do 3/2 pulldown, then just multiply the result by 2!?! Just seems crazy. And it can be really difficult getting a reliable answer from the Mfg to know for sure how a particular set handles it. :nono2:


ala most of the 120 hz TVs on the market today...


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## Tom Robertson (Nov 15, 2005)

Do'h, another thought occurs.

DIRECTV's Movies Now would be a perfect delivery for 1080p24 if they ever support it. 

Back to our regularly scheduled discussion. 

Cheers,
Tom


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## jediphish (Dec 4, 2005)

I haven't thought to ask this, but would it be necessary to upgrade equipment to be able to output a 24 frame rate signal at any rez? Could any of the current line of HD DVRs even do this if D* began transmitting such a signal?


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## Tom Robertson (Nov 15, 2005)

jediphish said:


> I haven't thought to ask this, but would it be necessary to upgrade equipment to be able to output a 24 frame rate signal at any rez? Could any of the current line of HD DVRs even do this if D* began transmitting such a signal?


I thought the HR20 broadcom chips did not support 1080p mode but some of the other info I thought I knew about those chips have definitely been shown to be wrong.

So I guess I'm not much help after all. 

Cheers,
Tom


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## DarinC (Aug 31, 2004)

And what about doing 3:2 pulldown, so that those who download 24fps content can watch it on their non 1080p/24 displays?


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## Tom Robertson (Nov 15, 2005)

I presume that if DIRECTV offers any 1080p content, it would only be in a situation where it would be properly convertible for other TVs as well.

Cheers,
Tom


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## jediphish (Dec 4, 2005)

DarinC said:


> And what about doing 3:2 pulldown, so that those who download 24fps content can watch it on their non 1080p/24 displays?


Maybe 24fps downloads via VOD or Movies Now could be labeled as such. Just like how someone with only an SD TV would not purchase an HD PPV, they would avoid it and purchase the regular PPV (some people do connect HD DVRs to SD-only TVs for more storage, better picture, etc.). By analogy, if one's display will not accept 24fps then the currently-provided HD PPV offerings are sufficient aren't they (I could be wrong...), therefore they could just purchase the regular HD PPV, as opposed to the premium 24fps HD PPV. Just thinking out loud here...

There is precedent out there for offering multiple versions of same thing (letterboxed SD PPV vs. fullscreen SD PPV).


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## cartrivision (Jul 25, 2007)

Tom Robertson said:


> For about the second time, your statement is only true in regards to a single frame. 1080i60 frames in succession are more "data" than 1080p24 but its not the native format used in the original movie. 3:2 conversion introduces artifacts that are not there in a 1080p24 transmission.
> 
> Cheers,
> Tom


You are incorrect. It doesn't matter that it's not the "native" format. A 1080i/60 encoding of 24fps source can be deinterlaced to recover 24 full progressive frames. It's not regular deinterlacing where every other field is combined together, because that would produce artifacting from video frames that spanned different frames of the 24fps source (i.e. the odd field of the video was from one film frame and the even field was from the next film frame). What is done instead is inverse 3:2 processing, (sometimes called inverse telecine processing), which yields 24 full progressive frames from the 1080i/60 video. When that inverse 3:2 processing is properly done with 1080i/60 video, the resulting 24 progressive frames (assembled together from 48 of the 60 fields contained in the 1080i/60 video) are no different from the 24 frames that you would get from a 1080p/24 encoding of the same 24fps source.

So there are no artifacts present that wouldn't also be there in 1080p/24. Artifacts can come from displaying the 24fps from either transmission method at a 60Hz frame rate on the television because the television's 60Hz frame rate isn't evenly divisible by 24 so some frames are displayed for 3/60th of a second and some for 2/60th of a second, but the same applies to 1080p24video when displayed on a 60Hz TV. The newer 120Hz displays can eliminate that artifact by displaying each frame 5 times, so each frame is displayed for exactly 1/24th of a second.



> BTW, why are you whining about counting?


Because I'm obsessed with how often people repeat the same incorrect statements about how 1080p/24 gives you something that 1080i/60 doesn't already provide.

Congratulations, your incorrect repeating of it made it 11.


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## jediphish (Dec 4, 2005)

cartrivision said:


> You are incorrect. It doesn't matter that it's not the "native" format. A 1080i/60 encoding of 24fps source can be deinterlaced to recover 24 full progressive frames. It's not regular deinterlacing where every other field is combined together, because that would produce artifacting from video frames that spanned different frames of the 24fps source (i.e. the odd field of the video was from one film frame and the even field was from the next film frame). What is done instead is inverse 3:2 processing, (sometimes called inverse telecine processing), which yields 24 full progressive frames from the 1080i/60 video. When that inverse 3:2 processing is properly done with 1080i/60 video, the resulting 24 progressive frames (assembled together from 48 of the 60 fields contained in the 1080i/60 video) are no different from the 24 frames that you would get from a 1080p/24 encoding of the same 24fps source.
> 
> So there are no artifacts present that wouldn't also be there in 1080p/24. Artifacts can come from displaying the 24fps from either transmission method at a 60Hz frame rate on the television because the television's 60Hz frame rate isn't evenly divisible by 24 so some frames are displayed for 3/60th of a second and some for 2/60th of a second, but the same applies to 1080p24video when displayed on a 60Hz TV. The newer 120Hz displays can eliminate that artifact by displaying each frame 5 times, so each frame is displayed for exactly 1/24th of a second.
> 
> ...


key word: Properly

There's effectively NO way to be absolutely certain that a set's deinterlacer will work "properly" with every single frame.

Or am I wrong and there is?


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## cartrivision (Jul 25, 2007)

DarinC said:


> 1080i/60 content would have already gone through a 3/2 pulldown to get to 60hz, then simply multiplied times two to get to 120hz. It _could_ have reverse pullodwn applied to it, then processed through proper 5/5, but Faroudja has a patent on that. I don't know if any TVs are doing that. I would expect that most only do a proper 5/5 if they are fed a 24hz input. Therefore, you end up with judder.


Many HDTVs these days have chip sets that can do reverse pulldown, and according to the datasheets for the chipsets used in DirecTv's HD DVRs, they can do it also.


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## cartrivision (Jul 25, 2007)

jediphish said:


> key word: Properly
> 
> There's effectively NO way to be absolutely certain that a set's deinterlacer will work "properly" with every single frame.
> 
> Or am I wrong and there is?


You are correct. According to posts over at avsforum, some HDTVs that claim to do reverse pulldown, don't always do it properly. As I understand it, there can be a flag in the video that tells the TV to do inverse pulldown and absent that flag some TVs can autodetect telecined video and still do the inverse processing despite the absence of the flag. I know that there are times when that autodetect function doesn't properly detect telecined source, so in those cases, it wouldn't be properly deinterlaced.


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## bruinfever (Jul 19, 2007)

The bottom line is DirecTV will supply what the market demands. If there is a reasonable demand for 1080p24 TV than they will have to do it unless they want to allow their competition to take over that market. Like anything, it has to be profitable. Directv didnt launch D10 and D11 because they love high-def TV, they did it because the market is here and they need to stay competitive to be on top..


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## cygnusloop (Jan 26, 2007)

Just to jump in...

1080p broadcast over sat, while kinda cool, still (for me) will not compete with Blu-ray. There is a lot more to PQ than just raw resolution. (Low) bitrate, IMO, is a bigger contributer to (crappy) PQ than resolution.

Don't get me wrong, I think DIRECTV's MPEG4 channels look fantastic when the source material is good. But, on my 60", it doesn't compete with Blu.

When some provider, any provider, talks about broadcasting 40+ Mbps 1080/24p (or 1080/60i for that matter), then I will get excited.


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## Brandon428 (Mar 21, 2007)

cygnusloop said:


> Just to jump in...
> 
> 1080p broadcast over sat, while kinda cool, still (for me) will not compete with Blu-ray. There is a lot more to PQ than just raw resolution. (Low) bitrate, IMO, is a bigger contributer to (crappy) PQ than resolution.
> 
> ...


I agree,also HD audio DTSHDMA and Dolby HD.


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## skaeight (Jan 15, 2004)

Actually, I think the bottom line is get a blu-ray player (ps3) and a netflix subscription. That way you can watch whatever movie you want in 1080p right now.

Interesting stuff about inverse telecine processing.


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## cartrivision (Jul 25, 2007)

cygnusloop said:


> Just to jump in...
> 
> 1080p broadcast over sat, while kinda cool, still (for me) will not compete with Blu-ray. There is a lot more to PQ than just raw resolution. (Low) bitrate, IMO, is a bigger contributer to (crappy) PQ than resolution.
> 
> ...


Exactly. The quality difference between DirecTV HD and BluRay isn't because BluRay is in 1080p, it's because the BluRay video isn't compressed as much.

That's why I think that people who wish for 1080p on DirecTv are foolish, but that might not stop the satellite companies marketing a few select channels in 1080p to take the money of foolish people who think that 1080p will give them BluRay quality.


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## Christopher Gould (Jan 14, 2007)

there is always hope that this bunch http://www.xstreamhd.com/index.html could get off the ground.


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## gregjones (Sep 20, 2007)

Everyone is ignoring the obvious question: WHY is Dish pushing info out about 1080p options?

Dish is behind in every real comparison. They have fewer options for expansion and a longer timeline to make it happen. Just like the loopy counting of their channels, they run their business on an impulse buy from an ill-informed consumer. They count on people not reading enough to know they are getting sold something that doesn't exist.

Dish cannot now deliver quality comparable to the MPEG4 HD channels. Without more bandwidth online, how do they possibly expect to deliver even higher bandwidth movies? It's simple: they will overcompress the 1080p movies until they look like 480p. Don't believe it? Look at what they have done to the HD channels they have.


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## Ken S (Feb 13, 2007)

cygnusloop said:


> Just to jump in...
> 
> 1080p broadcast over sat, while kinda cool, still (for me) will not compete with Blu-ray. There is a lot more to PQ than just raw resolution. (Low) bitrate, IMO, is a bigger contributer to (crappy) PQ than resolution.
> 
> ...


What he said.


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## DarinC (Aug 31, 2004)

cartrivision said:


> Many HDTVs these days have chip sets that can do reverse pulldown, and according to the datasheets for the chipsets used in DirecTv's HD DVRs, they can do it also.


Do you know of any source to determine which do? As it is, there's enough "24p capable" displays that can't even properly handle a 24hz input. Finding those that can also properly apply reverse pulldown from a 60hz input seems almost impossible. Any that do are often likely fairly expensive displays.

Considering how relatively new the HD standards are, it's really a shame they aren't better thought out. Broadcasters have to broadcast at a specific resolution 24x7, converting the content to that resolution regardless of the original format, because apparently some decoders can't seem to deal with resolution changing on the fly. Frame rate has to be converted in the front end, then possible re-converted on the downstream side, because most of the hardware can't handle different frame rates. Then there's all the issues on the audio side. If the whole system were designed for transmission to be in the native format, it would be much more efficient.


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## bruinfever (Jul 19, 2007)

Christopher Gould said:


> there is always hope that this bunch http://www.xstreamhd.com/index.html could get off the ground.


IMHO from the moment I saw this company as CES I didnt think they would get off the ground. Not a big enough market for this to work. If there was, than VOOM Satellite would still be around (not the channels).


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## cartrivision (Jul 25, 2007)

DarinC said:


> Do you know of any source to determine which do? As it is, there's enough "24p capable" displays that can't even properly handle a 24hz input. Finding those that can also properly apply reverse pulldown from a 60hz input seems almost impossible. Any that do are often likely fairly expensive displays.


I don't know of a reference list but those kind of details about individual models are often discussed over at avsforum.

I think you are right about the scarcity of TVs that can display 24p video. There are probably more TVs that can properly do reverse pulldown of 24fps source encoded in 1080i/60 video than can display 1080p/24 video. Most of the new 120Hz TVs can probably do both, but in either case (with 60Hz or 120Hz sets), the only advantage that 1080p/24 has over 1080i/60 is that it uses less total data to deliver the exact same picture information (since 1080i/60 has data for 30fps vs 24fps for 1080p/24), although after MPEG4 compression that difference in data size may go away.


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## Artwood (May 30, 2006)

A Pioneer Kuro elite plasma accepts and refreshes 1080p/24 at the perfect multiple of 72.

If it received 1080p/24 via satellite it would look great.

What part of not having to De-Interlace is a good thing do some people not understand?


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## cygnusloop (Jan 26, 2007)

DarinC said:


> Do you know of any source to determine which do?


Well, here's thread over at AVS that discusses HDTV's capable of reproducing 24Hz refresh at proper multiples. It's not about which HDTV's are capable of properly deinterlacing telecined material back to 24 Hz.

http://www.avsforum.com/avs-vb/showthread.php?t=997138

Personally, I trust the accuracy of his list, having done a great deal of my own research. But all the usual internet disclaimers apply.


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## DarinC (Aug 31, 2004)

cygnusloop said:


> Well, here's thread over at AVS that discusses HDTV's capable of reproducing 24Hz refresh at proper multiples. It's not about which HDTV's are capable of properly deinterlacing telecined material back to 24 Hz.


Yes, I'm aware of that list. That's part of my point... there are a LOT of TVs that didn't make the cut. It's surprising how many manufacturers go to the bother of introducing 120hz sets, then completely ignore one of the biggest reasons to go to 120hz... it's en even multiple of 30, 60 _and_ 24hz. You would think doing a 5:5 frame repeat would be simpler than 3:2, yet so many still just do the same thing they always did when they only had 60hz, then multiply that (juddered) result by 2. It seems they are more interested in being able to claim 3D compatibility than proper display of film sources, when the latter should be so easy to implement.



cartrivision said:


> I think you are right about the scarcity of TVs that can display 24p video. There are probably more TVs that can properly do reverse pulldown of 24fps source encoded in 1080i/60 video than can display 1080p/24 video.


I don't follow your logic there. Why would they go to the trouble of licensing and implementing the much more complex technology of inverse pulldown when they don't even have the ability to properly display the result? I would expect it to be the other way around: there's a subset of TVs that can show proper cadence when fed a 24hz input, then out of those there'd be a subset that can also properly detect and extract 24fps from a 60hz input.


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## gfrang (Aug 30, 2007)

My sony 40 v 3000 has 60hz refresh rate it does 24p at 48hz the bit rate is lower at 24p than 60p from BD disks.


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## jediphish (Dec 4, 2005)

skaeight said:


> Actually, I think the bottom line is get a blu-ray player (ps3) and a netflix subscription. That way you can watch whatever movie you want in 1080p right now.
> 
> Interesting stuff about inverse telecine processing.


People aren't buying Blu-Ray very fast it seems...

http://www.widescreenreview.com/news_detail.php?id=16131

This doesn't mean necessarily that people wouldn't enjoy 1080p 24fps content, but _maybe_ that they feel what they have already might be "good enough." _If_ my hypothesis is true, then why not throw small bones to those who would appreciate the advancement using the technology in place in their homes already (HD DVR).

I can promise you that I would pay at least a dollar more to get 1080p 24fps via VOD, maybe even $2. Way cheaper than investing add'l $$$ in a separate player and a subscription to one of the home-delivery Blu-Ray services or renting from BB or purchasing.

While I'm at it, I wonder if D* has considered a flat-rate VOD/PPV fee for all its offerings each month, to compete with Netflix and BBOnline for the consumer's add'l $$$.


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## gfrang (Aug 30, 2007)

Artwood said:


> A Pioneer Kuro elite plasma accepts and refreshes 1080p/24 at the perfect multiple of 72.
> 
> If it received 1080p/24 via satellite it would look great.
> 
> What part of not having to De-Interlace is a good thing do some people not understand?


It comes at a price its twice the bandwhit ,on BD disk it fits fine.Cable Satellite ota
big problem.


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## DarinC (Aug 31, 2004)

gfrang said:


> It comes at a price its twice the bandwhit ,on BD disk it fits fine.Cable Satellite ota
> big problem.


1080p/24 talkes slightly _less_ bandwidth than 1080i. I don't think anyone is suggesting they carry 1080p/60.


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## cartrivision (Jul 25, 2007)

DarinC said:


> I don't follow your logic there. Why would they go to the trouble of licensing and implementing the much more complex technology of inverse pulldown when they don't even have the ability to properly display the result? I would expect it to be the other way around: there's a subset of TVs that can show proper cadence when fed a 24hz input, then out of those there'd be a subset that can also properly detect and extract 24fps from a 60hz input.


It's no trouble at all. The chipset that is already in DirecTV's HD DVRs can do inverse pulldown and deliver true 1080p/24 video from a 1080i/60 satellite feed, so there is no reason to broadcast a pure 1080p/24 feed that only some TVs could display.... just use the capabilities of the chips in the DVR and let the user switch between 1080i/60 or 1080p/24 output.


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## Artwood (May 30, 2006)

I think in 2 or 3 years you'll see it offered on VOD--by then they can probably make a few bucks on it.


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## gfrang (Aug 30, 2007)

1080/24p is one of ASTC standards so you would think any digital tv that could pick it up and display it if they brodcast it ota.
But Directv receivers as of now can't output that signal?


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## Artwood (May 30, 2006)

Wouldn't it be a great world if everything INTERLACED was banned forever?

Wouldn't it be a great world if people didn't believe the fairy tale that inverse pulldown is always done perfectly--that de-interlacing is always done perfecty--Failing that wouldn't it be a great world if DirecTV sent nothing interlaced--then we wouldn't have to hear people here talk about how great interlacing is!

Do I inhabit the same universe or is it just barely conceivable that there are advantages to progressive signals over interlaced ones?

Remember before they decided on the HD standard that people waxed poetic about how much better progressive signals would be over interlaced ones?

Were all those people blooming idiots?

I guarantee you that the same people here who talk about how great 1080i/60 is will be the very same people who will proclaim how great 1080p/24 is the day that DirecTV offers it!

People here who are brave enough to dream of 1080p/24 might just figure that since it takes LESS BANDWIDTH than 1080i/60--and since that is the one holy reason around here that justifies DirecTV doing anything picture quality wise--that maybe just maybe DirecTV would consider doing it and making money off of it!

Please forgive people for having such dreams!

I guess it's not enough to want an infintessimal increase in picture quality that might come from 1080p/24--and it's not even enough to hope that DirecTV could make money by doing so!--what's really important is that whatever DirecTV is doing now is holy, just and unquestionable!

I think I've got it now--whatever is happening now is right and I promise to send DirecTV some money totally unconnected to my bill to show my appreciation!


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## Tom Robertson (Nov 15, 2005)

cartrivision said:


> It's no trouble at all. The chipset that is already in DirecTV's HD DVRs can do inverse pulldown and deliver true 1080p/24 video from a 1080i/60 satellite feed, so there is no reason to broadcast a pure 1080p/24 feed that only some TVs could display.... just use the capabilities of the chips in the DVR and let the user switch between 1080i/60 or 1080p/24 output.


Do you know, are the added frames in 1080i60 marked for easy deletion to revert to 1080p24?

Thanks for the info,
Tom


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## The Scotsman (Sep 1, 2007)

jediphish said:


> More and more panels are capable of displaying 1080p24fps in some proper multiple, eliminating some judder.
> 
> http://www.avsforum.com/avs-vb/showthread.php?t=997138
> 
> Not everyone has fast download speeds now but its a good bet that such DL speeds will likely increase.


I just checked the list on the link above and I was disappointed not to see my Sharp XV-Z20000 front projector listed. I updated the firmware almost a year ago to version 1.1.5. - I have a PS3 connected with 24 Hz enabled, and the 24 Hz does show on screen when I select Signal Info on the projector menu. I also have an HR20-700. Are there any XV-Z20000 owners who can confirm that this projector displays 24 Hz (or a multiple) without going via the 3:2 pulldown thing?

I know this isn't the projector forum. Please forgive my straying off topic.

Thanks
Archie


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## gfrang (Aug 30, 2007)

Artwood said:


> Wouldn't it be a great world if everything INTERLACED was banned forever?
> 
> Wouldn't it be a great world if people didn't believe the fairy tale that inverse pulldown is always done perfectly--that de-interlacing is always done perfecty--Failing that wouldn't it be a great world if DirecTV sent nothing interlaced--then we wouldn't have to hear people here talk about how great interlacing is!
> 
> ...


http://www.nostradamus.org/All your ansewers can be found here


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## cygnusloop (Jan 26, 2007)

Tom Robertson said:


> Do you know, are the added frames in 1080i60 marked for easy deletion to revert to 1080p24?
> 
> Thanks for the info,
> Tom


I don't believe that they are marked per se, Tom. A good inverse telecine processor, will recognize the cadence, and reorganize the 60Hz interlaced _fields _back into 24Hz _frames_.

However, with a lot of broadcast/cable networks, this process is doomed. A soon as a network overlays a 30fps bug/logo or promo, even worse a crawl, the detection can get flummoxed. This can cause some really strange effects from even a very good processor.

As such, I never use my Sony's "CineMotion" feature (it's pulldown processor) on broadcast television. It's performance on a well encoded 480/60i DVD is, however, another matter.


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## gfrang (Aug 30, 2007)

The thing whit 24p it was originally designed to work whit film source.I leave my CineMotion on auto it will only turn on if pulldown is detected.


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## cartrivision (Jul 25, 2007)

Tom Robertson said:


> Do you know, are the added frames in 1080i60 marked for easy deletion to revert to 1080p24?
> 
> Thanks for the info,
> Tom


I Don't know. I don't even know if the flag can be easily added before the video is uplinked to the satellite if it isn't there, or if it has to be done during the telecine process. There is also a process to automatically detect the 3:2 cadence of telecined video and do the inverse pulldown even without the presence of the flag.

Even though the HR20 doesn't output 1080p/24 video if it the source is 24fps, it does seem to detect it and do freeze frame (pause) different when it detects 24fps source&#8230; but it only seems to do this if the video is MPEG2.

If you freeze frame (24fps source) MPEG2 1080i/60 video on the HR20, you get a full resolution frame assembled from two interlaced fields, unlike the freeze frame that you get on the HR20 with any other interlaced video source, which is actually a freeze field (half the lines of vertical resolution in a frame).

With telecined MPEG2 1080i/60 video, the frame advance advances through 24 unique frames for each second of source video, showing none of the duplicate frames that you see when you frame advance through the same source encoded in MPEG4, where you see a 1-2-3-4-4 repeating cadence during frame advance. With MPEG2 video, you don't see every 4th frame repeated during frame advance so you see 24 frames per second of source and each frozen frame is a full frame, as opposed to MPEG4 video where frame advances show you every other field (at half vertical resolution), displaying 30 fields for each second of source.

The above phenomenon can be demonstrated by recording the same movie on HBOHD (MPEG2) and HBOWHD (MPEG4), and doing a freeze frame and frame advance on both.


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## jediphish (Dec 4, 2005)

So it appears we'll get some form of 1080p by years end - but will it be 24 fps?

http://www.dbstalk.com/showthread.php?t=134306


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## cartrivision (Jul 25, 2007)

jediphish said:


> So it appears we'll get some form of 1080p by years end - but will it be 24 fps?
> 
> http://www.dbstalk.com/showthread.php?t=134306


Since they are only saying that it for be for movies, I would assume yes, 1080p/24, but as has been discussed elsewhere in this thread, there is actually *less* temporal resolution and the same amount of spatial resolution in 1080p/24 compared to 1080i/60, so don't expect any improvement in resolution and don't expect any improvement in picture quality unless they significantly increase the bitrate.


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## gregjones (Sep 20, 2007)

cartrivision said:


> Since they are only saying that it for be for movies, I would assume yes, 1080p/24, but as has been discussed elsewhere in this thread, there is actually *less* temporal resolution and the same amount of spatial resolution in 1080p/24 compared to 1080i/60, so don't expect any improvement in resolution and don't expect any improvement in picture quality unless they significantly increase the bitrate.


How would increasing the bitrate improve image quality in frames that aren't there? By all accounts, the MPEG4 channels are not having their resolution reduced. Unless someone can show a percentage of pixels that are different from the source to the output, we don't know to what extent we are losing picture quality (if any).

In other words, do there exist sources (as delivered to DirecTV) clean enough for us to appreciate any opportunity for improved picture quality if it were an option?


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## evan_s (Mar 4, 2008)

There are plenty of Blu_ray and HD-DVD movies that are encoded at higher bit rates than DirecTV broadcasts channels at. Obviously DirecTV isn't going to start using them as a source but it shows that the content is out there that could be delivered to DirecTV in the future. Even if they keep the bit rate the same you should get some improvement in quality just because there is less information to compress into the same space with a 24p signal as opposed to a 60i signal(60i is 30 full frames a second). The biggest benefit of 24p how ever is eliminating the 2/3 telecine process that repeats particular frames a differing amount of times to get a 60i signal. This introduces a small amount of studder in smooth motion. With a 24p signal and a display capable of displaying a multiple of 24p this studder is eliminated. It is possible to do the inverstelecine and get the 24p signal out of the 60i but it isn't always a simple process and can be screwed up by something as simple as a network logo or other similar addition that isn't a 24p signal that has been telecined.


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## bruinfever (Jul 19, 2007)

I think the fact that DirecTV will be offering 1080p movies is a good sign for HD lovers who want high quality television and until recently, in my opinion, where largely ignored. I dont think the programming will be close to Blu-Ray quality, but its a good sign to see they are making efforts to compete.


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## gregjones (Sep 20, 2007)

evan_s said:


> There are plenty of Blu_ray and HD-DVD movies that are encoded at higher bit rates than DirecTV broadcasts channels at. Obviously DirecTV isn't going to start using them as a source but it shows that the content is out there that could be delivered to DirecTV in the future. Even if they keep the bit rate the same you should get some improvement in quality just because there is less information to compress into the same space with a 24p signal as opposed to a 60i signal(60i is 30 full frames a second). The biggest benefit of 24p how ever is eliminating the 2/3 telecine process that repeats particular frames a differing amount of times to get a 60i signal. This introduces a small amount of studder in smooth motion. With a 24p signal and a display capable of displaying a multiple of 24p this studder is eliminated. It is possible to do the inverstelecine and get the 24p signal out of the 60i but it isn't always a simple process and can be screwed up by something as simple as a network logo or other similar addition that isn't a 24p signal that has been telecined.


I agree with you to a point. But just because there is a source for a Blu-Ray disk doesn't mean there will be one available for a 1080p24 PPV. The compression algorithms already look for exactly the kind of redundancy you discuss.

I am very familiar with the pull-down process. I'm also familiar with the fact that this will only be the case for sets that correctly implemented a 1080p resolution at 120Hz. Very, very few do.

The improvements, if any, would be extremely marginal. Under the best circumstances, they could only be utilized on a very small minority of DirecTV's customers.

I understand all of the technical aspects. But for the possible return under perfect circumstances, you have to see this for what it is: marketing. DirecTV wants there to be no item that Dish can claim that they cannot. They want people that bought a 1080p set (though most of them have absolutely no understanding of it) to pay for 1080p programming (even though it may have no actual pixel-difference from 1080i programming).

PS Most people watching a Blu-Ray movie are watching it on a set that doesn't correctly handle 1080p24 either.


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## Tom Robertson (Nov 15, 2005)

Another point to consider between BD and DIRECTV. BD does not have to worry for bandwidth. They might be using a very minimalist MPEG4 encoding that gets them under 25 or 50GB per movie.

DIRECTV, with CABAC, likely in multipass encoding, can spend more CPU $$ ahead of time and still have the exact same picture quality as BD. (Actually, they can force their providers to do that, I should say.) 

Cheers,
Tom


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## DarinC (Aug 31, 2004)

gregjones said:


> But for the possible return under perfect circumstances, you have to see this for what it is: marketing.


While I'm sure there is a marketing aspect involved, that isn't necessarily the _only_ benefit. IF the STBs can take a 1080p/24 signal and do proper pulldown, then they can _replace_ 1080i/60 feeds of 24fps content with 1080p/24 feeds, and save some bandwidth (or use the same bandwidth and increase quality). Even IF the repeat flags are properly applied, there is still a compression efficiency benefit to encoding a progressive source vs. interlaced. Why not send content in the most efficient manner?


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## DarinC (Aug 31, 2004)

Tom Robertson said:


> Another point to consider between BD and DIRECTV. BD does not have to worry for bandwidth. They might be using a very minimalist MPEG4 encoding that gets them under 25 or 50GB per movie.
> 
> DIRECTV, with CABAC, likely in multipass encoding, can spend more CPU $$ ahead of time and still have the exact same picture quality as BD.


Hmmm, that seems a bit backwards to me. When creating BD, they can spend as much time and CPU time as they want to get the disc releases as good as they possibly can with their already abundant capacity. I don't care how well you encode a satellite transmission, I don't think it's going to have the same quality of something that uses 2x+ the bandwidth. There are definitely efficiency gains to be had with multipass encoding, but doing so (and maintaining that benefit to the customer) precludes doing statistical multiplexing. That should spell good things for quality, but can negatively impact their efficiency when carrying hundreds of channels. Is that the path they are going to take?

I remember years ago, before the Ka sats ever got deployed (and in fact, before it was even known that they were going to use MPEG4), there was a rumor that they were going to carry the feeds on the Ka sats straight through without any re-compression. That obviously went out the window when it was learned that they were going MPEG4. If they are going to be getting feeds in MPEG4 (which we already know is true, at least in some cases), and passing them on as is, that is certainly good (and interesting) news.


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## cartrivision (Jul 25, 2007)

gregjones said:


> How would increasing the bitrate improve image quality in frames that aren't there? By all accounts, the MPEG4 channels are not having their resolution reduced. Unless someone can show a percentage of pixels that are different from the source to the output, we don't know to what extent we are losing picture quality (if any).
> 
> In other words, do there exist sources (as delivered to DirecTV) clean enough for us to appreciate any opportunity for improved picture quality if it were an option?


It's quite simple. Increasing bitrate improves the picture quality by improving the quality in the frames that *are* already there. There is a lot more to PQ than resolution. We already have the full resolution of 1920x1080 bits, and going to 1080p24 won't increase that, but increasing the bitrate (of either 1080i or 1080p24) will decrease the macro-blocking and other digital artifacts caused by an insufficient bitrate.


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## Tom Robertson (Nov 15, 2005)

DarinC said:


> Hmmm, that seems a bit backwards to me. When creating BD, they can spend as much time and CPU time as they want to get the disc releases as good as they possibly can with their already abundant capacity. I don't care how well you encode a satellite transmission, I don't think it's going to have the same quality of something that uses 2x+ the bandwidth. There are definitely efficiency gains to be had with multipass encoding, but doing so (and maintaining that benefit to the customer) precludes doing statistical multiplexing. That should spell good things for quality, but can negatively impact their efficiency when carrying hundreds of channels. Is that the path they are going to take?
> 
> I remember years ago, before the Ka sats ever got deployed (and in fact, before it was even known that they were going to use MPEG4), there was a rumor that they were going to carry the feeds on the Ka sats straight through without any re-compression. That obviously went out the window when it was learned that they were going MPEG4. If they are going to be getting feeds in MPEG4 (which we already know is true, at least in some cases), and passing them on as is, that is certainly good (and interesting) news.


Would you spend a day on CPU $$ to compress a video to its smallest format possible when you only need a few minutes to encode it to the same picture quality? 

The other part of this equation is that to then decode an MPEG4 CABAC encoded stream, you need a whole lot more CPU in the set top box.

So I can see where BD authors won't spend the money yet DIRECTV (and their providers) might.

Cheers,
Tom


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## cartrivision (Jul 25, 2007)

DarinC said:


> While I'm sure there is a marketing aspect involved, that isn't necessarily the _only_ benefit. IF the STBs can take a 1080p/24 signal and do proper pulldown, then they can _replace_ 1080i/60 feeds of 24fps content with 1080p/24 feeds, and save some bandwidth (or use the same bandwidth and increase quality). Even IF the repeat flags are properly applied, there is still a compression efficiency benefit to encoding a progressive source vs. interlaced. Why not send content in the most efficient manner?


They could do that (broadcast a pure 1080p24 signal) but then they they would have to broadcast a duplicate 1080i60 version for everyone who can't display 1080p24, so they would end up using almost double the bandwidth to provide the same movie to all of their subscribers.

I suspect that what they will do is broadcast the movie in 1080i/60 (at a higher bitrate if they want to improve PQ) and then use the chipset inside the HR20s to do the inverse telecine processing that is required to convert 1080i60 to 1080p24.

Perhaps the chipsets in the HR20s are also capable of upconverting 1080p24 to 1080i60 and they will just broadcast a 1080p24 signal and let the receiver either pass it through or upconvert it to 1080i60.


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## cartrivision (Jul 25, 2007)

DarinC said:


> If they are going to be getting feeds in MPEG4 (which we already know is true, at least in some cases), and passing them on as is, that is certainly good (and interesting) news.


Where and when have they ever said that they were going to do that?


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## cartrivision (Jul 25, 2007)

gfrang said:


> 1080/24p is one of ASTC standards so you would think any digital tv that could pick it up and display it if they brodcast it ota.
> But Directv receivers as of now can't output that signal?


The chipsets in the DirecTV HD DVRs can output 1080p/24, and with today's announcement, I would assume that only a software change is required to get them to output 1080p/24 video.


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## DarinC (Aug 31, 2004)

Tom Robertson said:


> Would you spend a day on CPU $$ to compress a video to its smallest format possible when you only need a few minutes to encode it to the same picture quality?


Not to get it to it's smallest format possible, but if I were a studio releasing high value content that is undoubtedly going to be scrutinized for every little flaw, I would certainly spend a day of computer time to encode it to the maximum quality. In the little viewing of I've done of of DirecTV's MPEG4 offerings (I only had MPEG2 equipment until this month) I've already seen macroblocking. That's OK, it's not a lot, and I certainly don't expect BR quality out of bandwidth limited broadcast television. I've seen more on OTA MPEG2 broadcasts. And I'm not even a "tough" customer... my set is too small for my viewing distance to be overly demanding. But I have yet to see ANY problems with BR or HD-DVD releases.

I'm not knocking DirecTV's MPEG4 quality... for broadcast television, it is very good. But it's certainly not BR or HD-DVD. They just have WAY more bandwidth to throw at intensive scenes. And if you look at the bitrate meter, it is clear that the bits are definitely being heavily directed to where they are needed. That's just not practical in a broadcast situation, where the _aggregate _bandwidth is fixed. When you have a fixed size pipe, there's no huge advantage to multi-pass encoding... may as well run at full bandwidth all the time. Unless you are doing statistical multiplexing with other streams, at least you can kind of steer the bandwidth where it's needed. Not to the extent you can with a true variable bitrate system like disc storage (or "on demand" downloads), but better than just dividing the bandwidth evenly between the streams that are sharing the pipe.

BUT, there is one thing I've been wondering about since the comment you made about working with the networks to improve feed quality. If someone like HBO, or Discovery networks... networks that have multiple channels, were to stat-mux their feeds on their end into chunks that correlated bandwidth-wise to the size of DirecTV's transponders, THEN you could have the advantage of not needing a re-encode at DirecTV's end, without losing the efficiency gains of stat-muxing. And to keep this on-topic, they could be encoded at their native framerate to gain additional efficiency. But the downside there is: what may be right for DirecTV may not be what's right for cable.


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## DarinC (Aug 31, 2004)

cartrivision said:


> They could do that (broadcast a pure 1080p24 signal) but then they they would have to broadcast a duplicate 1080i60 version for everyone who can't display 1080p24, so they would end up using almost double the bandwidth to provide the same movie to all of their subscribers.


That's why I made it contingent on the STB being able to do proper pulldown on the 24fps feed. But if they can do inverse telecine, would think they could also do 3:2.


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## DarinC (Aug 31, 2004)

cartrivision said:


> Where and when have they ever said that they were going to do that?


Well, HBO is known. That's probably a sign of the future.

It's also interesting that HBO is dictating that HBO is dictating that the providers don't reduce the bitrate. Which would _suggest_ that the providers couldn't stat-mux, unless they considered it to be OK if the _average_ bitrate wasn't reduced. Really curious to see how this pans out. But it sounds like very good news for quality.


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## cygnusloop (Jan 26, 2007)

cartrivision said:


> They could do that (broadcast a pure 1080p24 signal) but then they they would have to broadcast a duplicate 1080i60 version for everyone who can't display 1080p24, so they would end up using almost double the bandwidth to provide the same movie to all of their subscribers.


No need to simulcast, I don't think. Just as the receiver can downconvert 1080/60i to 720p (or 480i for that matter), I would assume it would have the capability to convert 1080/24p to 1080/60i or 720p for those HDTV's (most) that are incapable of properly processing a 24Hz signal.



cartrivision said:


> I suspect that what they will do is broadcast the movie in 1080i/60 (at a higher bitrate if they want to improve PQ) and then use the chipset inside the HR20s to do the inverse telecine processing that is required to convert 1080i60 to 1080p24.


Interesting thought....

But isn't that exactly what they are already doing with HD PPV? The only difference would be the pulldown would be done in the HR2x and it would output the 1080/24p, instead of the inverse telecine process being done in a capable TV. The result, however (in theory) would be the same. It would be a bit disappointing if all they were doing with this is just to invoke the processing in the Broadcom chip to make the HR2x output 24Hz. I don't think we would ever be able to tell if the broadcast stream was intrinsically progressive or intrinsically interlaced, as there is no indicator light on the box. Hmmm....

Anyway, as I said _way, way_ upthread, I will get excited when I see an increase in bitrate. As you said, we already have the resolution, sending 1080/24p at the same bitrate as their current PPV offerings (on my equipment) makes no difference at all (again, in theory).


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## DarinC (Aug 31, 2004)

cygnusloop said:


> sending 1080/24p at the same bitrate as their current PPV offerings (on my equipment) makes no difference at all (again, in theory).


Except for the efficiency increase due to encoding a progressive signal. For equal bitrate, it _should_ result in a slight increase in quality. Especially if the repeat flags aren't perfectly implemented in a pre-pulled down signal.


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## cartrivision (Jul 25, 2007)

DarinC said:


> Well, HBO is known. That's probably a sign of the future.
> 
> It's also interesting that HBO is dictating that HBO is dictating that the providers don't reduce the bitrate. Which would _suggest_ that the providers couldn't stat-mux, unless they considered it to be OK if the _average_ bitrate wasn't reduced. Really curious to see how this pans out. But it sounds like very good news for quality.


How about a link a little more specific than a Google search for "HBO MPEG4"?

The fact that HBO is being distributed to Satellite and cable operators in MPEG4, and the fact that there have been unconfirmed reports that HBO was going to require minimum bitrates for redistribution, doesn't convincingly show that DirecTV is passing the MPEG4 stream through unaltered. In fact, all indications are that they are not doing that now on the MPEG4 HBO feeds (in direct contradiction to the unconfirmed reports that HBO was going to mandate it), so the question stands......

Where and when have they ever said that they were going to do that?


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## cartrivision (Jul 25, 2007)

DarinC said:


> That's why I made it contingent on the STB being able to do proper pulldown on the 24fps feed. But if they can do inverse telecine, would think they could also do 3:2.


You would think, but the datasheet only talks about the ability to do "reverse 3:2 pulldown", although not being listed there as a capability doesn't absolutely mean that the chip can't do it.


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## DarinC (Aug 31, 2004)

Read my post again. I said *IF *they were going to be getting feeds in MPEG4, and passing it on unencoded, it was good news. The only part I said we already knew was the first part. I assumed you were looking for confirmation that they'd be getting feeds in MPEG4.


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## cartrivision (Jul 25, 2007)

cygnusloop said:


> Interesting thought....
> 
> But isn't that exactly what they are already doing with HD PPV? The only difference would be the pulldown would be done in the HR2x and it would output the 1080/24p, instead of the inverse telecine process being done in a capable TV. The result, however (in theory) would be the same. It would be a bit disappointing if all they were doing with this is just to invoke the processing in the Broadcom chip to make the HR2x output 24Hz. I don't think we would ever be able to tell if the broadcast stream was intrinsically progressive or intrinsically interlaced, as there is no indicator light on the box. Hmmm....
> 
> Anyway, as I said _way, way_ upthread, I will get excited when I see an increase in bitrate. As you said, we already have the resolution, sending 1080/24p at the same bitrate as their current PPV offerings (on my equipment) makes no difference at all (again, in theory).


You are right, it (converting 1080i/60 to 1080p/24) wouldn't be much different from the way it's being done now.... only that the conversion to 1080p/24 would be done in the DirecTV box for people whose TVs can't do it, which is why I have been saying all along that 1080p broadcasts aren't necessarily anything to get all excited about. An increased bitrate is what will increase PQ.

Doing it the other way around (streaming to the box in 1080p/24) and upconverting that to 1080i/60 in the box theoretically might require slightly less bandwidth, but those bandwidth savings might disappear after the stream goes through MPEG4 encoding, and we don't know for sure if the DirecTV receivers can convert 1080p/24 to 1080i/60, although I would think that they could.


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## cartrivision (Jul 25, 2007)

DarinC said:


> That's why I made it contingent on the STB being able to do proper pulldown on the 24fps feed. But if they can do inverse telecine, would think they could also do 3:2.


OK, I misunderstood what you were trying to say here....



> If they are going to be getting feeds in MPEG4 (which we already know is true, at least in some cases), *and passing them on as is*, that is certainly good (and interesting) news.


I took that to mean that someone somewhere said that DirecTV would be passing the MPEG4 feeds unaltered. While that would be great for PQ, I really don't see that happening.


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## DarinC (Aug 31, 2004)

cartrivision said:


> I took that to mean that someone somewhere said that DirecTV would be passing the MPEG4 feeds unaltered. While that would be great for PQ, I really don't see that happening.


Yes, I was extrapolating from Tom's posts about DirecTV working with the providers for better feeds, and mentioning multi-pass encoding. The point being that multi-pass encoding essentially negates the use of stat-muxing, since that has to be done in real time. But if you combine Tom's post with the news of HBO distributing in MPEG4 _and_ dictating that the feed can't be further compressed, that does have some interesting implications.


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## gregjones (Sep 20, 2007)

cartrivision said:


> It's quite simple. Increasing bitrate improves the picture quality by improving the quality in the frames that *are* already there. There is a lot more to PQ than resolution. We already have the full resolution of 1920x1080 bits, and going to 1080p24 won't increase that, but increasing the bitrate (of either 1080i or 1080p24) will decrease the macro-blocking and other digital artifacts caused by an insufficient bitrate.


Macro-blocking is the result of compressing the picture into larger squares (macro-blocks), effectively reducing the resolution. My point is that the only way to judge picture quality is to compare the source (pixel by pixel) to the result after decompression. Any other measure just doesn't matter.


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## gregjones (Sep 20, 2007)

DarinC said:


> Yes, I was extrapolating from Tom's posts about DirecTV working with the providers for better feeds, and mentioning multi-pass encoding. The point being that multi-pass encoding essentially negates the use of stat-muxing, since that has to be done in real time. But if you combine Tom's post with the news of HBO distributing in MPEG4 _and_ dictating that the feed can't be further compressed, that does have some interesting implications.


I agree. Multipass will result in the smallest amount of bandwidth with the least picture quality loss at the end. I am sure that DirecTV would be glad to pass on the feed as-is whenever possible.


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## cartrivision (Jul 25, 2007)

gregjones said:


> Macro-blocking is the result of compressing the picture into larger squares (macro-blocks), effectively reducing the resolution. My point is that the only way to judge picture quality is to compare the source (pixel by pixel) to the result after decompression. Any other measure just doesn't matter.


Regardless of what it is a result of, increasing the bitrate can reduce macroblocking, which in answer to your original question is how PQ can be increased without increasing the frame rate or the resolution of each frame. Even though macroblocking does temporarily reduce the resolution at times, that temporary reduction in resolution isn't typically taken into consideration when stating what the resolution of the encoded video is.


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## Artwood (May 30, 2006)

Is it OK to be in favor of increasing the bitrate?


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## cartrivision (Jul 25, 2007)

Artwood said:


> Is it OK to be in favor of increasing the bitrate?


Unfortunately, that still won't ever come close to providing that elusive uncompressed video that you dream you might find somewhere. 

As for the 1080p/24 content that DirecTV just announced that they plan to provide, I would think that that might use increased bandwidth for better PQ, but since most people think that being 1080p is what makes Blu-Ray better quality than the typical 1080i that they see, DirecTV's new offering will likely be marketed to the masses as better because it's "progressive" rather than better because it has a higher bitrate.


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## Tom Robertson (Nov 15, 2005)

gregjones said:


> Macro-blocking is the result of compressing the picture into larger squares (macro-blocks), effectively reducing the resolution. My point is that the only way to judge picture quality is to compare the source (pixel by pixel) to the result after decompression. Any other measure just doesn't matter.


MPEG4 (and MPEG2) are both variable loss compression algorithms ranging from totally lossless to totally crap.  Macro-blocking is not present "just because of" compression; but rather by how much. Bitrate is the driver as to when it occurs. (Tho various tweaks and multi-pass compression can minimize the artifact as well.)

Your basic point, the eyeball test, is so absolutely true in all cases.

Cheers,
Tom


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## Tom Robertson (Nov 15, 2005)

Artwood said:


> Is it OK to be in favor of increasing the bitrate?


Only to the degree necessary to get the picture quality to the level it is indistinguishable from the providers source material. Beyond that, you'd be looking at stats not the picture itself. 

Some of the more highly compressed channels still have awesome pictures because the library of material was pre-compressed via ton's of computing power and multi-pass MPEG4 CABAC encoding. (No, can't name names, sorry.)

Cheers,
Tom


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## gregjones (Sep 20, 2007)

Tom Robertson said:


> Only to the degree necessary to get the picture quality to the level it is indistinguishable from the providers source material. Beyond that, you'd be looking at stats not the picture itself.
> 
> Some of the more highly compressed channels still have awesome pictures because the library of material was pre-compressed via ton's of computing power and multi-pass MPEG4 CABAC encoding. (No, can't name names, sorry.)
> 
> ...


Thank you for stating that so well, Tom. More bitrate doesn't improve picture quality in some cases. Sometimes an 8Mbps channel looks just as good as a 10 Mbps channel because they spent more effort compressing it in an efficient manner.


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## DarinC (Aug 31, 2004)

Tom Robertson said:


> Some of the more highly compressed channels still have awesome pictures because the library of material was pre-compressed via ton's of computing power and multi-pass MPEG4 CABAC encoding.


I'd probably guess PPV and DoD.


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## gregjones (Sep 20, 2007)

Tom Robertson said:


> Some of the more highly compressed channels still have awesome pictures because the library of material was pre-compressed via ton's of computing power and multi-pass MPEG4 CABAC encoding. (No, can't name names, sorry.)


And it would seem entirely logical that channels with high-repeat content (like HBO) would go through this process once for each item and be able to reap the benefits over and over.


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## DarinC (Aug 31, 2004)

gregjones said:


> And it would seem entirely logical that channels with high-repeat content (like HBO) would go through this process once for each item and be able to reap the benefits over and over.


But here's the issue that keeps throwing a wrench in that concept in my head: Generally speaking, multi-pass encoding is figuring out where to put your bits... finding the scenes that can give up some bits and still look good, and the demanding scenes that require a lot of them. The result is a variable bit rate encode. The problem with that is, when HBO transmits that data to the providers, they do so over fixed bandwidth pipes. So the pipe has to be at least as big as the bandwidth peaks in the content. But the other parts of the content that don't take up the full bandwidth of the pipe... that was wasted work. Why work so hard on moving the bits around when you have a fixed bandwidth pipe? If your goal is to produce good PQ at a fixed bandwidth, you don't need multi-pass to do that, as long as you have the processing power to do it in real time.

That's why I thought perhaps it applied to PPV and DoD... content that is not being broadcast live to DirecTV, but rather stored on their end, then sent to the customer. In the case of PPV, they could still pre-encode it, then stat-mux it in with other content, but don't allow bits to be taken from the PPV stream. In essence, the bandwidth left over for the other channels would vary, and they would stat-mux among themselves with the left over (and varying) bandwidth.

And that's why I suggested earlier that it seemed like the best solution for someone like HBO would be to stat-mux their various channels to the providers, then let DirecTV re-distribute that feed as is... pre-statmuxed. It still probably wouldn't be multi-passed, but at least it would make the best of the bandwidth available, while not needing to be re-encoded.

But who knows. :whatdidid


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## gregjones (Sep 20, 2007)

DarinC said:


> But here's the issue that keeps throwing a wrench in that concept in my head: Generally speaking, multi-pass encoding is figuring out where to put your bits... finding the scenes that can give up some bits and still look good, and the demanding scenes that require a lot of them. The result is a variable bit rate encode. The problem with that is, when HBO transmits that data to the providers, they do so over fixed bandwidth pipes. So the pipe has to be at least as big as the bandwidth peaks in the content. But the other parts of the content that don't take up the full bandwidth of the pipe... that was wasted work. Why work so hard on moving the bits around when you have a fixed bandwidth pipe? If your goal is to produce good PQ at a fixed bandwidth, you don't need multi-pass to do that, as long as you have the processing power to do it in real time.
> 
> That's why I thought perhaps it applied to PPV and DoD... content that is not being broadcast live to DirecTV, but rather stored on their end, then sent to the customer. In the case of PPV, they could still pre-encode it, then stat-mux it in with other content, but don't allow bits to be taken from the PPV stream. In essence, the bandwidth left over for the other channels would vary, and they would stat-mux among themselves with the left over (and varying) bandwidth.
> 
> ...


HBO can do the multipass because they have the library. There is no penalty for not using all the bandwidth of a fixed bandwidth delivery (to DirecTV). The payoff is in having the majority of the compression done where it can be most effective and less lossy.

Even though the pipe is fixed from HBO to DirecTV, you have to consider that they will be sending multiple streams simultaneously. You either manage to quality or to bandwidth. I am suggesting that you let HBO manage to quality through the multipass. This will give the best result across all of their channels. Then as DirecTV has all of the streams, the can manage the maximum aggregate bandwidth as a whole (ideally by giving priority to specific channels over less watched channels on the same transponder).

I like this plan because it lets each party do what they are best at accomplishing: HBO manages the quality of their library, DirecTV manages aggregate bandwidth only when HBO failed to get the total under the available bandwidth. This gets DirecTV out of the bandwidth (quality) management business most of the time.


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## DarinC (Aug 31, 2004)

gregjones said:


> There is no penalty for not using all the bandwidth of a fixed bandwidth delivery (to DirecTV). The payoff is in having the majority of the compression done where it can be most effective and less lossy.


There may not be a penalty, but there is also no benefit in not using all the bandwidth of a fixed bandwidth pipe. I just don't see where the payoff is... in a best case multi-passed encode with the most demanding scenes getting 8Mbps, and the less intensive scenes getting 1Mbps, compared to a CBR encode at a constant 8Mbps. How is the former better than the latter? Assuming you're using the same algorithms, the most demanding scenes should look the same, and the less demanding scenes should actually be more accurate in the CBR scenario (regardless of how noticeable it may be).


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## gregjones (Sep 20, 2007)

DarinC said:


> There may not be a penalty, but there is also no benefit in not using all the bandwidth of a fixed bandwidth pipe. I just don't see where the payoff is... in a best case multi-passed encode with the most demanding scenes getting 8Mbps, and the less intensive scenes getting 1Mbps, compared to a CBR encode at a constant 8Mbps. How is the former better than the latter? Assuming you're using the same algorithms, the most demanding scenes should look the same, and the less demanding scenes should actually be more accurate in the CBR scenario (regardless of how noticeable it may be).


The benefit is that these movies are shown over and over. If they maintain a constant quality (% original pixels correct), the bandwidth will go up and down. Sometimes it will not matter if the content uses an additional 1 Mbps, and another time it will. You encode the movies the best way and accept that sometimes you use less bandwidth than available. If they manage to quality instead of bandwidth, this will work. In some scenes, nothing will be gained by using an additional 1-2 Mbps. The model you propose would use this bandwidth because it is there. The model I propose would not use it: sometimes this would be important in managing the bandwidth on a transponder and other times it wouldn't.


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## DarinC (Aug 31, 2004)

gregjones said:


> If they manage to quality instead of bandwidth, this will work.


They have to manage to bandwidth, regardless. They still can't exceed the size of their pipe. When encoding, you ALWAYS have parameters that include max bitrate. The only difference is whether or not they try to reduce below this threshhold during less intensive scenes.


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## gregjones (Sep 20, 2007)

DarinC said:


> They have to manage to bandwidth, regardless. They still can't exceed the size of their pipe. When encoding, you ALWAYS have parameters that include max bitrate. The only difference is whether or not they try to reduce below this threshhold during less intensive scenes.


And they should because if they encode them once, they will never know what shows will be on at the same time. You can manage to use 100% bandwidth across all channels best using stat-mux real-time. This provides less picture quality though.

So the choice is to deliver better picture quality consistency by multi-pass encoding once or to use 100% bandwidth and less consistent picture quality by stat-mux.


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## Artwood (May 30, 2006)

Stat-mux real time should be against the law.


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