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Topic: How can I properly create and then playback 6-Channel WAV files from M (Read 3568 times) previous topic - next topic
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How can I properly create and then playback 6-Channel WAV files from M

Hi, I have a few MLP files that were taken from a friend's home made DVD-Audio disc using DVD-A Explorer. Obviously I can play the DVD-Audio fine, downmixed from 6-channel, but I'd prefer to have the files in my playlist in Windows Media Player along with the rest of my audio. I tried using SurCode MLP to decode the MLPs into three stereo WAV files (left/right, centre/LFE, side-l/side-r), but I'm not sure how to proceed from there (or even if the WAVs generated are correct!).

I tried using WaveWizard to merge the files (using the in-built DVD-A to Wave setting), but the merged file either doesn't playback on WMP11 at all (no codec) or, if I tell fddshow to decode it, it ends up as not sounding right (some channels are missing - and I'm only listening through headphones, so I don't know if the WAV file has not merged properly or if it's just the codec not downmixing properly). I did try turning on the mixer settings in fddshow but it didn't seem to affect playback at all...

Anyway, basically, could anyone tell me the steps to get from MLP -> 6-Channel WAV file that can be played back in WMP11 as normal, with the option to downmix to stereo, OR tell me how to make a 6-Channel WAV file from an MLP and also a stereo version of the same file for headphone usage.


Any help will be much appreciated!

How can I properly create and then playback 6-Channel WAV files from M

Reply #1 –
Quote from: DragonQ on
I tried using SurCode MLP to decode the MLPs into three stereo WAV files [..] but I'm not sure [..] even if the WAVs generated are correct!.

You could open them in an audio editor and check the contents, i.e. if the channel supposed to carry LFE information appears like that, if the rear channels carry mostly reverb, etc. If you have access to Sound Forge, you could zoom all the way in and check the actual bit depth, if in doubt.

Windows Media would not play 24 bit files if it cannot find 24-bit hardware, for example. Maybe the number of channels was the issue in your case. Open the multiplexed WAV audio in Audacity and see if all the channels appear as they should (since you can only listen to stereo for now). I remember that WaveWizard did not set the channel mask required for multichannel audio.

Quote
tell me how to make a 6-Channel WAV file from an MLP and also a stereo version of the same file for headphone usage.

I would archive all the 6 channels bit identical into a FLAC file for future use. Then downmix the multichannel file to stereo using Foobar2000 and create a hi quality lossy file for actual listening.

How can I properly create and then playback 6-Channel WAV files from M

Reply #2 –
Thank you for replying.

After checking Audacity it appears the 3 stereo files SurCod MLP creates are correct. However, when using WaveWizard or Audacity to combine the files it always sounds distorted when I listen to it (crackles in loud noises especially), so something must be going wrong. I'll do some more investigating with Audacity in the mean time.

EDIT: It seems when I play the 3 stereo files in Audaticy, split each stereo track so I have 6 mono sources, the crackling only happens when I add the centre track (with most of the vocals) to the front left and right channels. However, playing the centre channel or either left/right channel by itself appears to have no distortion O_o

In fact it's a similar distortion one of my friends gets when playing DVD-Audio discs because it gets downsampled to 48kHz....but why would the audio be downsampled on my laptop when using Audacity?? I definitely have a 24-Bit 96kHz capable sound card!

How can I properly create and then playback 6-Channel WAV files from M

Reply #3 –
OK, what I've done now is taken the 3 stereo tracks made by SurCode MLP, turned them into 6 mono WAVs using Audacity, and then merged them in the order lf, rf, c, lfe, ls, rs  using WaveWizard.

So I now have a 6-Channel 24-Bit 96kHz WAV file. Great, but the problem of actually playing it remains. If I open it in foobar2000 and turn on the "Downmix 5.1 to Stereo" option it seems to play very well. However, using fddshow in WMP11 or using Audacity to play it still results in distortion and crackling. The problem is, it might just be the software or the sound card that is not downmixing it properly to stereo - in which case I can just make all the 6-Channel WAVs now for later use...but I have no way of knowing that, it might still be that the WAVs weren't created properly or something else.
 

How can I properly create and then playback 6-Channel WAV files from M

Reply #4 –
Quote
OK, what I've done now is taken the 3 stereo tracks made by SurCode MLP, turned them into 6 mono WAVs using Audacity, and then merged them in the order lf, rf, c, lfe, ls, rs  using WaveWizard.

You could skip this step if you use Minnetonka Disc Welder. It outputs 1 wav file for each channel. I feel that any further discussion concerning this paid sofware should be done in private.

I dunno what exactly causes the distortion you're hearing. Maybe its clipping? Perphaps ffdshow or other component is using up all CPU time..   I just tried playing my 24-bit/6ch/FLAC streams using DirectShow. I had to use Ac3Filter to downmix it to stereo and truncate to 16-bit. To do this I had to enable uncompressed "PCM" processing in ac3filter. This is however not a good solution since now all audio passes trhu ac3filter, with dynamic range procession that is needed for movie soundtracks.

If each individual channel or L/R - Lo/Ro pair plays without distortions I can't see why assume that the whole file is somehow invalid.