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Discussion Starter #1
as has been written on this board, powerdvd downsamples the bitstream before sending it out the spdif. i wondered why and so i did this test. this is the setup i use:


Motherboard: 9npa+ultra, CPU: amd x2 4800, nvidia 8800gt,

lg combo drive ggc-h20L, OS vista32,

latest nforce drivers and video drivers for vista32

latest realtek drivers for vista are v6251

coaxial output from motherboard


powerdvd 3319a updated to 3516



when pirates of the caribbean 3 is played from the LG drive, the sound is great- the preamp is a tag McLaren AV32r and registers dolbydigital. the motherboard coaxial output sound also works well with theatertek when standard definition dvds are played - either from a dvd or from a rip.


so i added an rme digipad soundcard to the htpc. this is an excellent card and has very low jitter with an awesomely low noise floor. Using the xp drivers (rme told me they would work with vista32 but not 64) i get beautiful sound with theatertek playing regular dvd but none with powerdvd with the same regular dvd disc or file. of course, i also get no sound when playing the bluray disc or its ripped/converted-to-iso file.theatertek allows me to specifically select the rme soundcard whereas powerdvd is lacking in this regard. although i can choose spdif in the configuration, once the movie is started, that option disappears from the audio choices.


To make sure i am not seeing some bizarreness with the lg drive, i downloaded a dolby digital encoded wave file. SURROUNDTEST_DD_640.wav. Same thing happens - great sound with theatertek through the rme card, none with powerdvd. would guess that powerdvd cannot pass the audio bitstream outside of windows. same thing happens with windows media player - no sound(but then you would have expected that).


similar sound problems would occur with other sound cards if they operate outside of the windows kernel-it all depends on the drivers. it seems to me that powerdvd is running the sound through the windows kernel. this is probably a deliberate choice for drm control of the audio. so, in short, i do not think there will be any fix for this. in fact, i think the only way we will ever get true hd out of powerdvd is from the analog jacks, probably for the same drm driven reason.


i tried adding spdifer to the mix but it didnt help. maybe i wasnt setting it up correctly. i'll try adding ac-3 as wellbut i dont think the time investment will pay off.
 

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Quote:
Originally Posted by karos /forum/post/12852884


as has been written on this board, powerdvd downsamples the bitstream before sending it out the spdif. i wondered why and so i did this test. this is the setup i use:

PowerDVD (or any program) outputting HD audio through S/PDIF is going to have to downsample it. S/PDIF isn't really capable of high sampling rates and bit/word lengths in anything other than 2ch stereo (and even that is rarely used--many receivers probably wouldn't handle it anyway).


For multichannel audio through S/PDIF you've only really got a handful of options--DD/DD-EX, DTS/DTS-ES, DTS 96/24, and that's about all I can think of. None of those should be "downsampled" by PDVD when passed through because they are just streams which are passed to the receiver/decoder. For PDVD to be "downsampling" anything with those it would have to decode the stream, then downsample it, then re-encode it--which is clearly not happening. What does seem to be happening is some kind of fooling with DD streams though, some kind of dynamic range compression or something (which could be applied to the DD signal before passing it).


For HD tracks like LPCM, Dolby TrueHD, DTS HD/HD-MA, then sure they might be downsampled but they have to be anyway to get encoded to any of the multi-channel standards that S/PDIF supports.


The real issue is when the HD tracks get downsampled before they are passed to the sound device for analog output or for LPCM output via HDMI. There's a problem because this is neither necessary or desired.


But for S/PDIF, there's no complaints to be made. Except of course the fact that encoding/transcoding DTS by PDVD is absolutely horrendous and (for me at least) transcoding to AC-3 is not an option either because it's always greyed out.


As for it not working with your soundcard, that has little to do with "downsampling" if we're talking about S/PDIF output. That's more a drivers/windows issue if you ask me. Sure it would be nice if you could select your soundcard directly from PDVD and have it send audio like that, but given how bad PDVD is already that's really wishful thinking that it would ever happen.

Quote:
Originally Posted by karos /forum/post/12852884


similar sound problems would occur with other sound cards if they operate outside of the windows kernel-it all depends on the drivers. it seems to me that powerdvd is running the sound through the windows kernel.

Of course it is, why wouldn't it? Particularly in Vista, there's no reason for it to do anything "outside of Windows". Cyberlink's program is so clearly lazily developed that it would be a miracle if they didn't use normal Windows sound handling to do sound. That would require far too much work for them and it seems like they are barely interested in putting in the work to have the program work for BD/HD playback in the first place; nevermind out of Windows sound routines.

Quote:
Originally Posted by karos /forum/post/12852884


this is probably a deliberate choice for drm control of the audio.
Huh??? What does passing DD/DTS over S/PDIF in Windows have to do with "drm". Seems like that's a buzzword/punchline used to "explain" any "problems" encountered...


Sure we can say that for it's handling of HD audio tracks and Cyberlink themselves even gave that as the reason why these tracks are downsampled once decoded, before the sound driver. But again, I fail to see how this has anything to do with passing S/PDIF audio.

Quote:
Originally Posted by karos /forum/post/12852884


so, in short, i do not think there will be any fix for this. in fact, i think the only way we will ever get true hd out of powerdvd is from the analog jacks, probably for the same drm driven reason.

Fix for what now?
TrueHD can't be passed over S/PDIF, and even if you did throw the data over an S/PDIF stream somehow, what receiver would expect and decode TrueHD from an S/PDIF stream? It just isn't done.


Are you really expecting to somehow get Dolby TrueHD over S/PDIF or am I misunderstanding you somehow? If you are, trust me it has nothing to do with PDVD. Show me one other device on the market that will output TrueHD on S/PDIF. Also show me a receiever that says it decodes TrueHD from S/PDIF.


TrueHD over HDMI is another story but I thought that PDVD could pass that if you had an HDMI 1.3 output device in the computer (?) Though I could be wrong there.
 

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Discussion Starter #3
thank you for your informative reply. i did abbreviate my thoughts and it did come out jumbled a little.


first, i am stumped why theatertek will play a dolby digital audio test file flawlessly over either the motherboard spdif or the rme card spdif whereas powerdvd will only play it over the motherboard spdif. this is in vista32. i will set up an xp partition on the same machine to test that os as well. when theatertek plays the dolby digital test file, my preamp correctly reports 44khz. when power dvd tries to play it, the preamp locks onto 48khz but nosound is forthcoming.


i assume (perhaps incorrectly) that powerdvd cannot send audio over ASIO. but rather routes it through the operating system audio mixing kernels- i realize in vista this is completely different than xp-i think they did away with directsound but am not clear on the names and processing paths that are used.


I concluded by hypothesizing that the need(design) for powerdvd to route spdif through the os is a security measure. and that is how they get the sound downsampled to 48 khz. i then presumed that cyberlink will do the same thing with trueHD-they will never pass a native digital bitstream over hdmi for the same reason. no way to downsample the audio resolution efficiently-is there a law that forces them to do this? even in china?. i think the reason that video is allowed to go digital over hdmi is that it is such an enourmous amount of data-that capture of a single movie from the raw uncompressed hdmi output would require over a hundred gigabytes.
 

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Discussion Starter #4
oh well, in xp, powerdvd plays the audio fine through the rme card. This tells me that the rme drivers are not working well in vista32.
 

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Quote:
Originally Posted by karos /forum/post/12854462


first, i am stumped why theatertek will play a dolby digital audio test file flawlessly over either the motherboard spdif or the rme card spdif whereas powerdvd will only play it over the motherboard spdif. this is in vista32. i will set up an xp partition on the same machine to test that os as well. when theatertek plays the dolby digital test file, my preamp correctly reports 44khz. when power dvd tries to play it, the preamp locks onto 48khz but nosound is forthcoming.

Hmm, so the test file is in 44.1kHz? I've never seen a DD stream in anything other than 48kHz but if that particular file is indeed 44.1 then you should get 44.1 from Vista and whatever soundcard you've setup. Vista's sound handlind is actually far better than XPs and it does away with a lot of the need for going around the Windows kernel. Though I would imagine some purists still have that desire, Vista combined with a Azalia or better sound chipset will do nearly the equivalent just fine.


A couple questions--have you installed the lastest drivers for the card, are they Vista specific, and, have you set options for the S/PDIF output with Vista's own audio control panel applet? Meaning have you set Vista's sound options for DD, DTS and all the sampling rates that you can decode with your receiver?


As a side note, Vista's "test outputs" aren't really correct for some reason, at least not for me. For example when I "test" DTS output my receiver just shows "decode not ready" but I can indeed decode DTS and DTS works fine when played back over the PC. For 2ch sampling rates I get much of the same--while 192kHz/24-bit doesn't really play back from the Vista test output, but when I play the test from my soundcards driver control panel applet, it seems to work fine and my receiver actually decodes it stating a 192kHz input (it actually surprised me my receiver could do it). So what I did was I just checked all the boxes in the Vista control panel thing, except WMV Audio which I know for sure my receiver cannot decode natively.

Quote:
Originally Posted by karos /forum/post/12854462


i assume (perhaps incorrectly) that powerdvd cannot send audio over ASIO. but rather routes it through the operating system audio mixing kernels- i realize in vista this is completely different than xp-i think they did away with directsound but am not clear on the names and processing paths that are used.

I think you're correct as well. IMO Cyberlink doesn't really put too much effort into their "programming" it seems... I actually think PDVD should be some kind of freeware beta, LOL. (I've actually seen freeware "beta" programs that work better overall, perhaps not for video but just in general. I mean charging $100 for a program that barely does what it's supposed to is a little ridiculous!)

Quote:
Originally Posted by karos /forum/post/12854462


I concluded by hypothesizing that the need(design) for powerdvd to route spdif through the os is a security measure. and that is how they get the sound downsampled to 48 khz.

The routing of sound through the OS isn't really a security measure per se in this case. The downsampling occurs at PDVD, before the sound data is released to (or gets to) the driver. So the "security" is happening at PDVD and really doesn't have much to do with Windows in a strict sense. I.e. Cyberlink could have just as easily left the sound intact, still using Windows routines. But they downsample, if required (note that some LPCM HD tracks aren't more than 48kHz anyway) before outputting sound to the driver.


However for standard DD/DTS streams this is irrelevant as the quality will never be even at that point, which is why I was saying what I did about S/PDIF. Again multi-channel over S/PDIF is typically limited to DD or DTS. These formats max out at 640kbps for 6/7 channels for DD (and 448 is the max on DVD) and 1536kbps for that many channels with DTS. Even downsampled 48/16 LPCM x 6/7 is far greater than even DTS can provide, so for S/PDIF the downsampling issue isn't important because you'd never get that (even downsampled) quality anyway.

Quote:
Originally Posted by karos /forum/post/12854462


i then presumed that cyberlink will do the same thing with trueHD-they will never pass a native digital bitstream over hdmi for the same reason.

This I'm not sure about. That is I know (from the information on these forums) PDVD will decode TrueHD and pass it to the sound driver after downsampling, just like LPCM; but what I don't know is if you are able to pass the TrueHD stream from PDVD to the sound driver, if you have an HDMI 1.3 capable output device. I *think* you can, but I'm not sure.


Quote:
Originally Posted by karos /forum/post/12854462


no way to downsample the audio resolution efficiently-is there a law that forces them to do this? even in china?.

Cyberlink states that they "have to" do this, though there's no telling whether they are lying about that. What strikes me right away is that they do things very half-assed and it wouldn't surprise me if the easier way to do things is the way they do it. I'm not sure if it's easier or harder for them to downsample audio before it goes to the driver but I would imagine that it would have to be "required" by BD/HD-DVD or it would have to be easier to do it that way. That is if it weren't required (as they claim) it would have to be the easier/cheaper way to do it. Which way it is, I'm not sure; however from the information posted here they do downsample LPCM and decoded TrueHD & DTS-MA/MA-HD.

Quote:
Originally Posted by karos /forum/post/12854462


i think the reason that video is allowed to go digital over hdmi is that it is such an enourmous amount of data-that capture of a single movie from the raw uncompressed hdmi output would require over a hundred gigabytes.

It would. It would be a pretty silly idea to try to capture the [uncompressed] digital video out and then recompress it, however make no mistake this video output is still protected by HDCP! That's right you wouldn't be able to "capture" that output properly unless you had an HDCP compliant device doing the capturing. And at that no HDCP device would allow you to record such content as movies. AnyDVD will remove that protection/neccesity for HDCP, but just given it on it's own you still can't do it (eventhough it's a silly enterprise no one would take part in as ripping the already compressed content is much easier).


Really, it's nearly the same thing with the audio. In order to "capture" this native LPCM (or other format) audio, you would need to capture it from the program to the sound driver. Assuming PDVD did not downsample, it's true that the computer PCI/PCI-e bus is not going to be "proteected" but then you would require some program to "capture" the audio from PDVD before it got to the sound driver. While this is certainly possible, who in their right mind would do that? Why on earth would someone want to capture the audio in this fashion and disregard the video? I guess if you love to listen to movie tracks without the video it's great
And heck even if you're strange enough to do that, would you care if they are 48/16 or 192/24? Of course not. Even if you wanted to capture the audio from a relative handful of music concert discs out there, is it really worth it to bother with this nonsense? Of course not, but that's the way they've made it, unfortunately



The DRM honestly makes no sense, but what's more sad is that the idiots that mandate this stuff? They probably make more money on January 1st of the year (where they aren't working because it's a holiday) than the majority of the population makes in a year!



I'm not against DRM per se (as most people you'll find on this forum probably are) but I am against stupidity. If downsampling the audio just because it passes over an unprotected computer bus is required by BD/HD-DVD standards, that's just pure stupidity! Again you can't really do anything about it if it's the reality. I really hope it's just Cyberlink BSing about it, but you never know...

Quote:
Originally Posted by karos /forum/post/12859525


oh well, in xp, powerdvd plays the audio fine through the rme card. This tells me that the rme drivers are not working well in vista32.

Ahh, okay yeah it might be bad drivers--that's always a possibility. Check those Vista options again though, I think those might play a role in the possible output.
 

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Quote:
Originally Posted by ES_Revenge /forum/post/12853120


The real issue is when the HD tracks get downsampled before they are passed to the sound device for analog output or for LPCM output via HDMI. There's a problem because this is neither necessary or desired.

I haven't been following all the PDVD threads, but I thought that they didn't downsample when your output is set to analog. I just bought a sound with 6 channel output because I thought it won't be downsampled.
 

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Quote:
Originally Posted by ES_Revenge /forum/post/12865246



Cyberlink states that they "have to" do this, though there's no telling whether they are lying about that. What strikes me right away is that they do things very half-assed and it wouldn't surprise me if the easier way to do things is the way they do it. I'm not sure if it's easier or harder for them to downsample audio before it goes to the driver but I would imagine that it would have to be "required" by BD/HD-DVD or it would have to be easier to do it that way. That is if it weren't required (as they claim) it would have to be the easier/cheaper way to do it. Which way it is, I'm not sure; however from the information posted here they do downsample LPCM and decoded TrueHD & DTS-MA/MA-HD.




Really, it's nearly the same thing with the audio. In order to "capture" this native LPCM (or other format) audio, you would need to capture it from the program to the sound driver. Assuming PDVD did not downsample, it's true that the computer PCI/PCI-e bus is not going to be "proteected" but then you would require some program to "capture" the audio from PDVD before it got to the sound driver. While this is certainly possible, who in their right mind would do that? Why on earth would someone want to capture the audio in this fashion and disregard the video? I guess if you love to listen to movie tracks without the video it's great
And heck even if you're strange enough to do that, would you care if they are 48/16 or 192/24? Of course not. Even if you wanted to capture the audio from a relative handful of music concert discs out there, is it really worth it to bother with this nonsense? Of course not, but that's the way they've made it, unfortunately



The DRM honestly makes no sense, but what's more sad is that the idiots that mandate this stuff? They probably make more money on January 1st of the year (where they aren't working because it's a holiday) than the majority of the population makes in a year!



I'm not against DRM per se (as most people you'll find on this forum probably are) but I am against stupidity. If downsampling the audio just because it passes over an unprotected computer bus is required by BD/HD-DVD standards, that's just pure stupidity! Again you can't really do anything about it if it's the reality. I really hope it's just Cyberlink BSing about it, but you never know...



Ahh, okay yeah it might be bad drivers--that's always a possibility. Check those Vista options again though, I think those might play a role in the possible output.


yeah it's really stupid. people barely even trade lossless 3 minute songs, mostly crappy 128 rate mp3 and they think people will trade 2 hour long 24bit 48-96kHz movie SOUNDTRACKS and lose sales because of this
.


they are nuts.


just annoying legit customers for zero gain, and possible some actual loss of sales by people made overly annoyed.


it also forces people to start digging around places looking for ways to get around stuff, which certainly has to be counter to their desires.


also, i think the claim that they have to protect this audio is a rather strict reading of the AACS docs that seems a bit dubious to me.


this is probably the stupest case of studio pressured DRM. studios literally get zero benefit and possible a little loss!


seriously what worry do they have for multiGB sound tracks being traded. and if soundstracks are to be traded do those people care between 16bit/48Khz and 24 or 96Khz??


ridiculous.
 
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