SPDIF with AC97

[zadzior]

Hi

I have
vlc 0.7.1
realtec ac97 with spdif out
win xp

When i play DTS Wav i have only stereo (PCM) output
(i see it on my external spdif decoder)
For exaple when i use power dvd with DVDs it works fine

i set option SPDIF output of course in VLC

[zadzior]

i set option SPDIF output of course in VLC

I can add that DTS DVDs in VLC works fine too

only DTS WAV not works as DTS ;(

I try single DTS WAV or mounted DTS Audio and results are
the same (PCM stereo out)

[donesteban]

I believe we are dealing with the same problem. Please see my topic "Forcing S/PDIF Out".

The DTS wav files on your hard drive are probably sampled at 44,100 hz which is the CD sample frequency. When your sound card is dealing with a physical DVD, it is reading 48000hz sample rate whether it is dts or ac3. Most dts files around (alt.binaries.sounds.dts) are already downconverted to 44100.

Why this causes VLC to make stereo out of them I do not know, but it happens to me with my Onkyo USB-to-Toslink device. Your AC97 is also on USB, right?

Your card evidently isn't trying to play the dts at 48000 as my onboard card does. That produces either silence or white-noise, not stereo. I believe you are one step closer to a solution than I.

There's a good chance that JRiver Media Jukebox will play the dts files from your hard drive through the AC97. http://www.musicex.com/mediajukebox

If that works for you, it will only remain to figure out how to do it with VLC, so one player and one soundcard will do everything.

I'll follow this thread...

donEsteban

[zadzior]

[quote="donesteban"]I believe we are dealing with the same problem. Please see my topic "Forcing S/PDIF Out".

The DTS wav files on your hard drive are probably sampled at 44,100 hz which is the CD sample frequency. When your sound card is dealing with a physical DVD, it is reading 48000hz sample rate whether it is dts or ac3. Most dts files around (alt.binaries.sounds.dts) are already downconverted to 44100.

NO, my card has only 44100 support, it is very simple codec on my
mainboard


Why this causes VLC to make stereo out of them I do not know, but it happens to me with my Onkyo USB-to-Toslink device. Your AC97 is also on USB, right?

No, it is on my MB

Your card evidently isn't trying to play the dts at 48000 as my onboard card does. That produces either silence or white-noise, not stereo. I believe you are one step closer to a solution than I.

But why audio DTS from DVD's is playing OK ?


There's a good chance that JRiver Media Jukebox will play the dts files from your hard drive through the AC97. http://www.musicex.com/mediajukebox

T'll check it

[donesteban]

Why do DVD's play OK? Well this answer won't sound consistent with what you say, but based on my hanging out in alt.audio.dts for a couple of years, if your sound card is playing dvd's it supports 48000 sample rate. All "hardware" dvd players are cd-audio compatible, so it supports 44100 too. DTS audio tracks on a DVD are 48000. DTS content in .wav files is almost certainly 44100.

PowerDVD, for example, supports DTS, but only from the physical DVD Disc, or if you happen to have a .dts file (48000) on your hard drive. It will not play a 44100 dts wave file from you hard drive.

Before we get flagged for off-topic, this is to find what it would take to play dts-cd files from a pc hard drive with VLC Media Player. If you can play them with Media Jukebox, as I can, you will confirm that player "B" does it, and "A" does not. If you cannot, and you were getting noise, your card would be resampling. If you are still getting PCM Stereo, something supernatural is going on because Media Jukebox doesn't decode dts, and indeed thinks it is playing a stereo .wav file.

That's why I was saying undecoded s/pdif out may have to be "forced" somehow.

[Guest]

I have the exact same problem with my soundMax onboard card on the ASUS P4P800. This is very weird, cause any other software would just pass out the white noise, but VLC passes out the CORRECT content, only not as a DTS file, but as a standard WAV PCM. Any insight would be helpful.

Best regards,

Oded S.