# Dish Pvr's still slow at changing channels?



## Simtare (Dec 24, 2004)

Hi all, Long ago I had a 501 from dish. I sold it because I channel surf constantly and the 501 was very slow to change channels, compared to my 4900. I guess it was the buffer filling each time I switched. 
I now have an 811 and want a pvr whenever the mpg 4 gear comes out. My question is do dish pvrs still take a long time to lock onto channels when you switch them?


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## LtMunst (Aug 24, 2005)

Simtare said:


> My question is do dish pvrs still take a long time to lock onto channels when you switch them?


Compared to what? I know my 942 is much quicker than the Motorola HD box from Comcast.


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## fwampler (Dec 2, 2005)

Simtare said:


> Hi all, Long ago I had a 501 from dish. I sold it because I channel surf constantly and the 501 was very slow to change channels, compared to my 4900. I guess it was the buffer filling each time I switched.
> I now have an 811 and want a pvr whenever the mpg 4 gear comes out. My question is do dish pvrs still take a long time to lock onto channels when you switch them?


I've found I can use the browse button and can get to channels quick and easy! The show information is transparent and overlays just the top and bottom portions of the screen. You can move up or down channels and/or forward in time. Very quick. Really changed my surfing habits.

Usually though I'm watching recorded event. Works then too though. BTW, mine is the 625.


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## finniganps (Jan 23, 2004)

The PVR's are all slower than the non-PVR's because of the buffering (among other things). The least pause will come from NON-pvr devices.


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## navychop (Jul 13, 2005)

Use the Guide button.


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## Big Bob (May 13, 2002)

If you thought it was bad to channel surf now, wait till mpeg4 comes out.


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## DISHDADDY (Dec 26, 2005)

if it is changeing slow try to do a soft reset. that usually solves the problem.


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## Ron Barry (Dec 10, 2002)

Big Bob said:


> If you thought it was bad to channel surf now, wait till mpeg4 comes out.


Why would you think that channel changing would be effected by moving to MPEG4?


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## James Long (Apr 17, 2003)

More overhead in the decoding.

JL


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## Ron Barry (Dec 10, 2002)

Really?? Hmmm. I will have to think about that one. I would expect that the MPEG4 throughput would have to be the same as MPEG2 to have the ability to watch live MPEG4 so I would expect the higher overhead of MPEG to be handled by MPEG4 encoder and would provide the same throughput. Guess the question is... Is the processes switching between two MPEG4 channels significantly slower because of the extra overhead or is the extra overhead compensated by the difference in hardware between a MPEG2 box and an MPEG4 box? 

Guess time will tell. Was curious of Big Bob as some personal experience with channel switching on a MPEG4 box. Hmm wonder how the D* MPEG4 boxes on switching on MPEG4 streams feel. Even given that, I would expect switching speed to improve as they performance tune the new platforms. 

Just my thoughts.


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## James Long (Apr 17, 2003)

Just mine too. Changing channels is a lot of work. Blank screen, send switch command for proper satellite/polarity, change tuning, lock in on signal, find which streams within signal are needed for audio/video, send audio to the decoder and video to its decoder. As soon as one has audio allow it to pass. As soon as one has video allow it to pass.

Video is comprised of key frames and changes frames. The decoder pretty much has to wait for a key frame before displaying an image. Compression can be helped by lowering the number of key frames (on slow changing video) but that does add to the time it takes to sync to the channel.

I'm not sure how MPEG4 is set up - how often key frames are sent and how long it takes the video to lock in - but every time I think of increasing compression I think of a system that takes longer to get on track when pointed at a new video feed.

Perhaps MPEG4 might take a second to get in sync and MPEG2 only .8 seconds. That's up to those with fast stopwatches to figure out. Once we see MPEG4 streams we can find out first hand and stop "just thinking" ... it really isn't THAT long of a pause between channels anyways. After having Dish for a few years I have almost forgotten what changing analog cable channels looks like. 

I notice a pause on my ATSC tuner as well changing between OTA feeds. It's a computer. It isn't going to be instant.

JL


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## fwampler (Dec 2, 2005)

James Long said:


> Just mine too. Changing channels is a lot of work. Blank screen, send switch command for proper satellite/polarity, change tuning, lock in on signal, find which streams within signal are needed for audio/video, send audio to the decoder and video to its decoder. As soon as one has audio allow it to pass. As soon as one has video allow it to pass.
> 
> Video is comprised of key frames and changes frames. The decoder pretty much has to wait for a key frame before displaying an image. Compression can be helped by lowering the number of key frames (on slow changing video) but that does add to the time it takes to sync to the channel. <Snip>
> 
> JL


Thanks for the explanation James. I had no idea that so much was going on when the channels changed. I soon found that cruising with the browse button was much more satisfying response-time wise.


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## Ron Barry (Dec 10, 2002)

It is funny for a number of us how we interact with electronic devices changes with each device to minimize agrevation and maximums throughput. It used to be that people would browse what was one by quickly changing channels. Now a large percentage of people do it using the EPG. That is how I do it. 

As for key frames. you get a number of key frames a second. I would expect at least 4, but I could be wrong. I don't think key frames should be much of an issue here but I could be wrong.


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## James Long (Apr 17, 2003)

Ron Barry said:


> It used to be that people would browse what was one by quickly changing channels.


There is always a little extra overhead on the PVRs since writing to the disk is involved before displaying the content. In that 'used to be' memory was that on E*? On analog cable and analog OTA changes are pretty quick, but there is a lot less going on.

JL


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## navychop (Jul 13, 2005)

Since it's a continuous non-compressed signal, you can start displaying an analog signal at any instant. There are no key frames to wait for. I remember moving to satellite from analog cable and being surprised at the slow channel change. There was even more of a channel changing delay when I moved to ATSC OTA. So for DISH I use the guide button- the EPG. This is much better, because I get a synopsis displayed with each channel. Much better than the old channel surfing. Since I watch so little OTA, the lack of guide/PSIP data doesn't matter much. I go online and plan my OTA from online guides and set recorders or watch live. I only watch ER & DH live, and not all the time even for them.


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## Rob O (Dec 19, 2005)

It's funny reading this discussion. Remember the days when channel surfing meant standing in front of the tube and turning the dial, or gasp, reading the TV guide to plan out that evening's viewing? Boy do I love technology!:grin:


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## navychop (Jul 13, 2005)

Don't forget, after turning the dial you often had to move the antenna!


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## liferules (Aug 14, 2005)

navychop said:


> Don't forget, after turning the dial you often had to move the antenna!


Yeah, I remember, my father had one of those electric contraptions that would rotate the roof antenna when your dialed it with a box placed on top of the TV (which was a whopping 14"...

Those were the good old days!


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