# Dishwire/Firewire problem explained!!!



## jimgali (Apr 16, 2004)

Hi, This is My very first post. I have a computer(amd athlon xp 3200+) with a dtv tuner(MIT 100) card and a firewire card. The bus that the cards ride on is called the PCI bus. The hdtv tuner card can record on the hard drive or output to my JVC D-VHS deck(30000u). But when I try to copy from the hard drive (seagate 80GB 7200 rpm) to the D-VHS deck the picture breaks up like the connection is not fast enough. The hard drive also runs on the PCI bus. The problem is the PCI bus on todays computers is not fast enough to handle the load of data that is required buy the hard drive, firewire port, and data processing for the CPU. The 921 is moslty off the shelf parts and technology and E* did not reinvent the wheel when they made the 921 and this machine must use the PCI bus. They must have not tested the function of the firewire port until after production when the software was finished. E* could design custom hardware and buy back all the bad units or let you just record live events from the tuner with the harddrive not active, but too many tech calls if this was the case. So we all know the final outcome rip the port off and also all of us E* customers.


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## Mike Richardson (Jun 12, 2003)

There are millions of Macintosh computers that have Firewire capability directly on the motherboard with no PCI bus in between the two. In fact, there are millions of Macintosh computers that don't have a PCI bus at all. It would be foolish for Echostar to include a PCI bus on the 921 just so they can have Firewire; instead, they are most likely using an off the shelf Firewire chipset that was designed to be part of the motherboard.


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## jimgali (Apr 16, 2004)

The 921 definitley has PCI slots in it. A power mac that could run the 921 functions has PCI slots and macs have almost the same limitaions in their bus designs. The 921 could not use mac tech it is too expensive for the design. The PCI bus connects the cpu frontside bus and interface cards, the firewire card or "chip" as you said and the harddrive. A chip that is on the board will still ride the PCI bus unless it is intergrated in a custom design(which they didnt). These 3 items make the PCI bus too slow to run the firewire function without errors.


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## Guest (Apr 17, 2004)

jimgali said:


> The 921 definitley has PCI slots in it. A power mac that could run the 921 functions has PCI slots and macs have almost the same limitaions in their bus designs. The 921 could not use mac tech it is too expensive for the design. The PCI bus connects the cpu frontside bus and interface cards, the firewire card or "chip" as you said and the harddrive. A chip that is on the board will still ride the PCI bus unless it is intergrated in a custom design(which they didnt). These 3 items make the PCI bus too slow to run the firewire function without errors.


You're wrong about many things.

1) The PCI bus in PCs runs at 133MB/s (that a big B as in bytes). HDTV is I believe 27Mbps (little b as in bits) which is roughly 4MB/s

2) While the above is a theoreticl max, I have pushed 80+ MB/s though the PCI bus on my 4 year old athlon box. I was benchmarking drives connected to a RAID card on the bus.

3) Motherboards with builtin firewire may be connected directly to the southbridge, bypassing the PCI bus altogether.

As for your problems, I'd suspect whatever software you're using to stream out through the firewire, a bads cable, or possibly a flaky or incompatible (with the DVHS) firewire card.


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## Mike Richardson (Jun 12, 2003)

jimgali said:


> The 921 could not use mac tech it is too expensive for the design.


Macs don't use proprietary firewire chipsets, they use standard off the shelf parts which actually keeps costs down.


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## Foxbat (Aug 1, 2003)

jimgali,
Are you sure it just isn't Windoze?


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## mindwarp (May 19, 2003)

Jim, check out whatever programs are you running in the background of your athlon box... I have a 2800+ made by me, and data transfers are very fast, maybe it is a conflict with the irq's or something else. But... I dont really own a card like that, a DTV Tuner? Like Directv or digital tv? can you explain that one?


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## MarkA (Mar 23, 2002)

Actually, the macs with onboard Firewire STILL use a PCI connection between the memory controller and the firewire chipset... it's just all onboard (no pci slot)


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## BigMike (Dec 4, 2003)

This sounds more like a slow hard drive issue than anything else. I've done firewire captures from my video camera and also done video capture through an ATI AIW card using no compression on my PC with a T-bird 1400 cpu. The only time I've had break up problems is when capturing to slower hard drives. I do all my capture now to a RAID-0 drive array which gives me plenty of throughput, and the 2 drives in the array are only 100MB drives with 2MB cache.


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## mindwarp (May 19, 2003)

That was the reoute I was trying to go, maybe it is something slowing down the computer.


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## Kagato (Jul 1, 2002)

jimgali said:


> Hi, This is My very first post. I have a computer(amd athlon xp 3200+) with a dtv tuner(MIT 100) card and a firewire card. The bus that the cards ride on is called the PCI bus. The hdtv tuner card can record on the hard drive or output to my JVC D-VHS deck(30000u). But when I try to copy from the hard drive (seagate 80GB 7200 rpm) to the D-VHS deck the picture breaks up like the connection is not fast enough. The hard drive also runs on the PCI bus. The problem is the PCI bus on todays computers is not fast enough to handle the load of data that is required buy the hard drive, firewire port, and data processing for the CPU. The 921 is moslty off the shelf parts and technology and E* did not reinvent the wheel when they made the 921 and this machine must use the PCI bus. They must have not tested the function of the firewire port until after production when the software was finished. E* could design custom hardware and buy back all the bad units or let you just record live events from the tuner with the harddrive not active, but too many tech calls if this was the case. So we all know the final outcome rip the port off and also all of us E* customers.


What your describing is PCI Bus Mastering not set up correctly or a DMA mode not set correctly on your Hard Drive. You can certainly dump a HD Transport stream from a hard drive to a DVHS deck. I used to do this all the time with my HiPix capture card and a generic FireWire card on an Athlon 1800.

You've got the right idea however. Something is slowing down the process enough that it causes the MPEG Transport Stream to run out of buffer. Most likely this is because of the hardware encryption layer they would need to add for an actual production product. You're in a situation where you need to pass the stream from the hard drive, to a decoder process, to a decrypt process, to a transcode process (so the TS stream meets JVC's specs), and finally out to firewire. (Maybe add a 5C process in there somewhere.) My guess is when they initially tested this they weren't dealing with as many things (Like decrypt and 5C). That's a lot of places where something could be a stopper. Some of these processes are hardware driven, some are software.

I would say that Dish could make it work, but they would either have to save off programming unencrypted, or modify the hardware.


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## SpenceJT (Dec 27, 2002)

Check your drive's level of fragmentation. I do some basement video editing on my Intel P4 (and P3 before that) and have had no problems with editing, rendering and outputing back to tape via my firewire port.


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