Defeating DVD-A copy prevention flag - diyAudio
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Old 30th March 2005, 06:32 PM   #1
pooge is offline pooge  United States
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Default Defeating DVD-A copy prevention flag

It there a way to defeat the DVD copy prevention flag so that full 24/96 output can be output on SPDIF? It this a simple matter of cutting a trace, changing a logic hi to lo, etc., or is it embedded in the data and read only in the D/A chip?

The DVD players known to me that ignore the copy flag don't appear to be great shakes when it comes to playing DVD video, according to Secrets of Home Theater Benchmarks. It's hard to reliably find out which players ignore the flag. Are there any good lists around that keep up with the new players for this info?
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Old 31st March 2005, 05:39 PM   #2
macboy is offline macboy  Canada
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I guess that the DIY solution would be to build a S/PDIF transmitter (or transmitters, for multi-channel) and feed it/them from the I2S signals going from the decoder to the DACs. The DACs definitely do not have any awareness of the copy flag; it is the decoder that does.
One caveat of this method: 192/24 DVD-A's will likely not work correctly, as S/PDIF is not specified to work at that data rate.
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Old 31st March 2005, 06:53 PM   #3
gmarsh is offline gmarsh  Canada
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Quote:
Originally posted by macboy
I guess that the DIY solution would be to build a S/PDIF transmitter (or transmitters, for multi-channel) and feed it/them from the I2S signals going from the decoder to the DACs. The DACs definitely do not have any awareness of the copy flag; it is the decoder that does.
One caveat of this method: 192/24 DVD-A's will likely not work correctly, as S/PDIF is not specified to work at that data rate.
AES/EBU can be run at 192Kbps - I've done it, using a CS8406/CS8416 combination, 100ft of Belden Brilliance and XLR connectors. There's Toshiba TORX/TOTX parts that handle 192kbps, and I see no reason why you can't do it with BNC or even RCA.

If the recording end is going to disk, then jitter isn't a problem. On the recording end, toss a Lynx 24/192 or similar card in a computer. Expensive, but it'll work.

I'm confident that someone's going to break DVD-A and MLP, and nobody will go through this hassle. It didn't take long for DeCSS to be broken...
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Old 31st March 2005, 09:13 PM   #4
pooge is offline pooge  United States
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Quote:
Originally posted by macboy
I guess that the DIY solution would be to build a S/PDIF transmitter (or transmitters, for multi-channel) and feed it/them from the I2S signals going from the decoder to the DACs. The DACs definitely do not have any awareness of the copy flag; it is the decoder that does.
One caveat of this method: 192/24 DVD-A's will likely not work correctly, as S/PDIF is not specified to work at that data rate.

24/192 will work on the coaxial output. Panasonic has some players that will do this, but will downconvert if copy protection is in the software.

It is Toslink that can't go beyond /96.

Your DIY idea is worth looking into. That is why I started this thread. It doesn't appear that commercial units will be sold without the copy protection. I was not looking for hacking the software, so much as determining if hardware changes could be accomplished. I'm not even looking to copy. I just want to get full fidelity to my D/A. I guess my question about something happening in the D/A was not well thought out, since the downconvert happens in the transport. So I really need to know where and by what function the downconvert happens; and to find out what, if any, hardware could be changed or modified to stop it, or how to build a transport from scratch without the downconvert.
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Old 1st April 2005, 03:24 PM   #5
A 8 is offline A 8  Sweden
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Quote:
It is Toslink that can't go beyond /96.
That is incorrect, Toshibas TOTR (X) 142 does up to 24/192.
I also noticed they are working on a solution for AV optical transfer that goes up to 500Mps
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