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SACD playback under Linux?
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The Seventh Taylor



Joined: 17 Aug 2007
Posts: 401

PostPosted: Thu Feb 28, 2008 9:12 pm    Post subject: SACD playback under Linux? Reply with quote

In another thread,
usernameuser wrote:
Hey guys do you think you can play SACD in Linux, if so it could be the first ever computer that plays SACD? can you imagine? and lets not stop there, perhaps you could rip the dsd track of SACD and burn your own mixes, or burn a DVD-A, if thats possible.
But probably not, knowing sony they probably restrict the SACD part of the PS3 with their hypervisor, or they built a separate chip that decodes SACD and its not accessible though Linux.
Is any Linux Masters around maybe they'll know for sure.


An intriguing question. For all I know, access to certain parts of PlayStation3 hardware is restricted or altogether blocked to Linux, notably the RSX processor. Now the GPU is probably not at all needed for DSD decoding/SACD playback. Has anyone tried what can be done?
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Superman



Joined: 17 Jan 2008
Posts: 19
Location: Metropolis

PostPosted: Wed Mar 26, 2008 11:05 pm    Post subject: Reply with quote

Every device ever made that can play the DSD layer of a SACD uses a combination of hardware and software to read and decode it. Without the necessary SACD chip inside the player to verify it you can't play the SACD. It's why SACD's encryption scheme was never broken. It is currently impossible to play a SACD with a software only solution, hence why Linux playback for SACD is an impossibility. The right PS3s have the necessary chip for SACD playback. It's why SACD playback was removed from the 40 GB version. Dropping the SACD chip cut costs for it.
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The Seventh Taylor



Joined: 17 Aug 2007
Posts: 401

PostPosted: Thu Mar 27, 2008 7:36 am    Post subject: Reply with quote

Sorry, I realise I may not have formulated my question clear enough. I did not mean to ask whether the 40GB version could be made to play SACDs via a hack. I meant to ask (and so did the original poster, I think) whether on 20/60/80GB models the DSD data could be accessed under Linux.
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DVD-Audiophile



Joined: 09 Mar 2008
Posts: 6

PostPosted: Wed Apr 16, 2008 11:13 am    Post subject: Reply with quote

On a similar note, it's an interesting question whether with some hack under Linux the PS3 could be made to play DVD-Audio. Surely the technology is (more than) powerful enought to handle a 5.1-channel 24-bit 96 kHz audio stream (or a subset thereof) in PCM, DD or DTS. But is there some secret hardware requirement/restriction that makes this impossible or is it perhaps just software?
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michilumin



Joined: 22 Apr 2008
Posts: 10

PostPosted: Tue Apr 22, 2008 11:19 pm    Post subject: Reply with quote

In the case of DVD-A, no, no hardware would be needed. CPPM would have to be decrypted, and MLP (Now called True HD) would have to be decoded. This is already being done fully in the PS3 software as it stands. So while capability is definitely there, legitimacy of doing this is another question entirely.

Obviously the PS3 is already capable of this; there's an insignificant hardware issue of the 9.6 mbps data rate max of DVD-A exceeding the 6.4 mbps data rate of DVD-V; but I say insignificant as I'm sure the PS3 has a >1x DVD read capability.

As far as "hardware" needs for SACD; this is a bit of a mixed bag, too. Really, when it comes down to it, a SACD is a UDF 2.0 DVD-5 (or in some rare cases, (david bowie, roger waters) DVD-9.

There's the "story" of Pit Signal Processing, but there's a bit of debate as to whether or not that's really in use anymore. PSP actually produced a visible mark on the recorded surface of the disc - visible on VERY early SACDs as a faint image of the SACD logo. (Also see some PS2 releases which used PSP solely for this purpose.) These marks have disappeared from the discs likely due to the fact that it made the entire setup less error resilient. (You introduce known errors, you have less room to recover from unintended ones.) I strongly believe that PSP has been eliminated from all but the earliest SACD pressings; but I may be wrong.

The suggestive proof comes in the case that I've gotten some DVD readers to read the UDF structure of a SACD; (http://www.mindspring.com/~insomniaskunk/sacd/sacd3.jpg) though of course it is still encrypted at the file level. Actually usually its DST (lossless packing; we're talking one "layer" up from DSD) encoded, and then encrypted; so those two steps have to be overcome before you get what's essentially a DSDIFF file that can be parsed and fed to a ΔΣ-dac.

DST decoding can be done (and has been done, on the PC and in the PS3) in software. The PS3 has enough horsepower to process DSD and either quantize to PCM or feed DSD to the dacs (from what it looks like, they're doing a DSD->PCM quant in software); and both of these things could be done in linux.

I don't think anyone has the slightest idea how to get through the encryption on SACD yet; Too many folks are uninformed or haven't even tried, I think. Though, never say never.

Plenty of headway has been made in the DVD-A realm though. (See the Doom9 forums).

So I guess in theory, but not yet in practice:

-- Yes, SACD could be decoded in Linux; if the question of Pit Signal Processing is still in play, obviously the PS3 can do it, but it may not even be necessary.

-- Yes, the PS3 could likely decode DVD-A in Linux, even "soon"; likely just a matter of porting what's already out there.

So with some homebrew, the PS3 could be a hell of a universal player: DVD-A, SACD, BD...
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Jens



Joined: 11 Nov 2007
Posts: 99

PostPosted: Wed Apr 23, 2008 12:05 am    Post subject: Reply with quote

Interesting thoughts!

michilumin wrote:
Obviously the PS3 is already capable of this; there's an insignificant hardware issue of the 9.6 mbps data rate max of DVD-A exceeding the 6.4 mbps data rate of DVD-V; but I say insignificant as I'm sure the PS3 has a >1x DVD read capability.


As far as I'm aware, the maximum data rate for both DVD-A and DVD-V is 9.8 Mbps. Perhaps the 6.4 you mention is the max audio data rate for DVD-Video?

Quote:
There's the "story" of Pit Signal Processing, but there's a bit of debate as to whether or not that's really in use anymore. PSP actually produced a visible mark on the recorded surface of the disc - visible on VERY early SACDs as a faint image of the SACD logo. (Also see some PS2 releases which used PSP solely for this purpose.) These marks have disappeared from the discs likely due to the fact that it made the entire setup less error resilient. (You introduce known errors, you have less room to recover from unintended ones.) I strongly believe that PSP has been eliminated from all but the earliest SACD pressings; but I may be wrong.


What you're describing is the visual watermark -- something akin to the 'pit art' Warner at one stage proposed for SD/DVD. This has not been used on SACD commercially, I believe. I'm not sure for what reason but your suggestion of reliability sounds plausible.

I've read somewhere that SACD contains 4 levels of copy protection measures:
  • Visible watermark
  • SACD mark
  • Scrambled content
  • Invisible watermark

I'm not sure what the term PSP applies to precisely but I'd guess the last one. The first is probably not relevant, as discussed above. The second one for sure is handled in the front end, in hardware. The third and fourth one I'm not sure about.
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michilumin



Joined: 22 Apr 2008
Posts: 10

PostPosted: Wed Apr 23, 2008 6:56 am    Post subject: Reply with quote

I'm -pretty- sure that "SACD Mark" was simply TOC obfuscation... Some of these details were actually spoken of way back in 1998 but are hard to find now...

And i'm -pretty- sure that the "invisible watermark" and "visible watermark" are both a *result and function* of Pit Signal Processing.

Not trying to rebuke you because really the truth may be somewhere in between here; the documentation on this is hard to come by. I think a discussion on this would be good...

I just know it's not *impossible* to read the content of a SACD, and knowing that, likely not impossible to go further...

I'm just not sure how many folks have the time/motivation/patience to try to explore this much further; i think a lot of folks haven't tried because of the 'common knowledge' that it can't be done.
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Jens



Joined: 11 Nov 2007
Posts: 99

PostPosted: Wed Apr 23, 2008 10:11 pm    Post subject: Reply with quote

michilumin wrote:
I'm -pretty- sure that "SACD Mark" was simply TOC obfuscation...


I recall hearing about the ToC obfuscation too but I believe this SACD mark is some high-frequency analog signal that has to be processed in the front end. The drive will handle this (in the SACD-compatible models) but it's quite a different thing then.

Quote:
I just know it's not *impossible* to read the content of a SACD [...]; i think a lot of folks haven't tried because of the 'common knowledge' that it can't be done.


But then again there is no greater motivator than saying "it can't be done", isn't there? Wink
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The Seventh Taylor



Joined: 17 Aug 2007
Posts: 401

PostPosted: Wed May 14, 2008 5:00 am    Post subject: Reply with quote

DVD-Audiophile wrote:
On a similar note, it's an interesting question whether with some hack under Linux the PS3 could be made to play DVD-Audio. Surely the technology is (more than) powerful enought to handle a 5.1-channel 24-bit 96 kHz audio stream (or a subset thereof) in PCM, DD or DTS. But is there some secret hardware requirement/restriction that makes this impossible or is it perhaps just software?


I doubt it's that simple. Consider this: the DVD-Audio standard should be easily covered by any Blu-ray Disc player (and HD-DVD player). Most if not all can decode Dolby TrueHD (the new version of MLP), handle high-resolution multichannel PCM and can read DVDs, so technically there should be no issue.

Since many of them are made by companies from the one-time DVD-Audio camp like Pioneer, Panasonic (and Toshiba) there should be no licensing issue either.

In other words, DVD-Audio playback ought to be a feature they could basically give away for free, if only as an extra tick mark on the feature list. Yet (virtually) none do.
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Jens



Joined: 11 Nov 2007
Posts: 99

PostPosted: Sat May 17, 2008 8:59 pm    Post subject: Reply with quote

The Seventh Taylor wrote:
DVD-Audio playback ought to be a feature they could basically give away for free, if only as an extra tick mark on the feature list. Yet (virtually) none do.


Didn't one of Panasonic's BD players feature DVD-Audio playback?
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The Seventh Taylor



Joined: 17 Aug 2007
Posts: 401

PostPosted: Fri Jun 27, 2008 7:07 am    Post subject: Reply with quote

Jens wrote:
Didn't one of Panasonic's BD players feature DVD-Audio playback?


Yes, their first generation BD-10A reportedly but none after that.
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Jens



Joined: 11 Nov 2007
Posts: 99

PostPosted: Tue Jul 22, 2008 9:28 pm    Post subject: Reply with quote

My assumption until recently was that there were plenty of programs offering DVD-Audio ripping. In the meantime I've come to realize that although many programs call themselves "DVD Audio Rippers" (I've come across such claims from Xilisoft, CAS, KaosAudio/YASA, Acala, Jesterware, Aimersoft, 4Movy, iSkysoft, Apollo -- there is no end to the list, really) in fact none of them work with DVD-Audio. All they can do is rip the audio from a DVD-Video disc.

Now however I've come across an open source project called DVDAExplorer (discussed here) that promises to offer DVD-Audio playback -- and ripping -- on PCs. This sounds like an excellent way to start a DVD-Audio player for PS3's Linux environment.
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FunkyMonkey



Joined: 09 Nov 2007
Posts: 77

PostPosted: Tue Jul 22, 2008 10:27 pm    Post subject: Reply with quote

Jens wrote:
My assumption until recently was that there were plenty of programs offering DVD-Audio ripping. In the meantime I've come to realize that although many programs call themselves "DVD Audio Rippers" (I've come across such claims from Xilisoft, CAS, KaosAudio/YASA, Acala, Jesterware, Aimersoft, 4Movy, iSkysoft, Apollo -- there is no end to the list, really) in fact none of them work with DVD-Audio. All they can do is rip the audio from a DVD-Video disc.

Now however I've come across an open source project called DVDAExplorer (discussed here) that promises to offer DVD-Audio playback -- and ripping -- on PCs. This sounds like an excellent way to start a DVD-Audio player for PS3's Linux environment.


One would assume that there are no DVD-A drives for a PC though? In other words, is there hardware out there that allows this?
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Jens



Joined: 11 Nov 2007
Posts: 99

PostPosted: Wed Jul 23, 2008 6:43 am    Post subject: Reply with quote

FunkyMonkey wrote:
One would assume that there are no DVD-A drives for a PC though?


The point is: There is no such thing as a DVD-Audio drive. A DVD-Audio disc is simply a DVD-ROM disc with a particular type of audio files in specific folders -- the same way a DVD-Video disc is a DVD-ROM disc with specific audio and video files with a certain folders. These rules are in no way mutually exclusive, making it relatively easy to create a 'hybrid' DVD-Audio/Video disc.

So the differences are only in the 'back end' (the decoding part) and the copy protection, with CPPM being slightly more sophisticated than CSS, but cracked shortly after release.
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bogglor



Joined: 31 Jul 2008
Posts: 1

PostPosted: Thu Jul 31, 2008 4:03 pm    Post subject: on the topic of linux Reply with quote

I have been trying to get playback of 96khz multichannel WAV files ripped from a DVD-A (using DVDAExplorer 2008, mentioned above) to play on the PS3 under Yellow Dog Linux 6 to no avail. Apparently, the sound driver for Linux only has 2 channel support right now. And I don't think it understands how to pass data properly via HDMI connections either, so that's two problems that have yet to be overcome. Most software audio players like VLC or mplayer have options to output over the 2 things that engineers have traditionally coded support for: analog connections and SPDIF optical. If your PS3 is hooked up to your receiver via HDMI like many are, there's no software audio player that I know of that recognizes HDMI and will bitstream out to a receiver.
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