5.1 Audio CD from AC3 file

[pavment]

Need help here. I want to make a 5.1 Dolby Digital Audio CD, you know like the 5.1 DTS CDs, from DVD soundtracks. Here is what I have done, I demuxed the AC3 file. Then converted the 5.1 AC3 audio file to 5.1 wav format via AC3 tool. So now it's a wav file but maintains the 5.1 channel. However when I proceed to burn an Audio CD using the wav files with Nero 6 I get error message incompatible format. Is there any S/w to help me burn the 5.1 wav file as an Audio CD? BTW the AC3 and wav files play without a hiccup on my Audigy 2. So I know the file is not corrupted.

[risimmons]

Nero is right - Audio CD only supports 2 channel stereo.

As far as I know, the only consumer audio formats which support 5.1 channel are SACD and DVD-Audio, and they require compatible players. I don't think there's any burners available for SACD - not sure if standard DVD burners support DVD-Audio.

[Cornucopia]

Nero is right, but not specifically for the reasons you specified.

Yes, AudioCD supports only 2 channel (usually stereo), 16bit LPCM, 44100Hz tracks. What pavment is talking about isn't strictly an AudioCD anymore, it's a AC3-CD or a DTS-CD.

What's being done is the AC3 or DTS file (2ch, 5.1ch, whatever) is being encapsulated within a stereo WAV header (and footer), so the audioCD burning app will accept it like it would any other 2 ch WAV. As burned, the file is interleaved like this:

Regular Audio
(L=leftch, R=rightch, lo=lowbyte:bits0-7, hi=highbyte:bits8-15)

L-lo1 | L-lo2 | L-lo3...
L-hi1 | L-hi2 | L-hi3...
R-lo1 | R-lo2 | R-lo3...
R-hi1 | R-hi2 | R-hi3...

AC3

(L)byte1 | byte5 | byte9...
(L)byte2 | byte6 | byte10...
(R)byte3 | byte7 | byte11...
(R)byte4 | byte8 | byte12...

If this disc were to be played on a regular CD player--OUCH! Digital harsh noise.
But, if this disc is played on a CD player with PCM digital (like SPDIF or TOSLINK) out, or played on a DVD player with digital audio outs, and sent to a AC3 (or DTS if that's your style) decoder, you'll get great surround sound.
When it's sent down the digital line the interleave is undone like this:

byte1 | byte2 | byte3 | byte4 | byte5 | byte6...
So everythings cool on the decoder end.


Back to the beginning--
The problem with Nero is that it will be expecting a WAV with a sample rate of 44100Hz, but you're giving it a WAV that is 48000Hz!

These are the correct steps to get it burned:

1. Rip DVD
2. Demux AC3
3. Decode AC3 to 5 or 6 separate PCM WAV's
4. Sample rate convert each and every one of the WAV's from 48 to 44.1k
5. Re-encode the WAV's to 5.1 AC3--this time set for 44.1kHz
6. Save AC3 as AC3-WAV
7. Burn with Nero
8. Enjoy!

HTH,
Scott

[Psycho_Dad_Rules]

Hi all,

This can all be done way easier using the BeSure tool. It's a frontend for BeSweet and let you create DD5.1 wav file which are supported by Nero (or any other audio capable burning software) with only Freeware software. Or even to DTS cd's if you own/purchase SurcodeCD !!!

It lets you select a AC3 file or even a VOB file and create the required files for you, which you only need to burn to a regular audio cd !!!

I can't remeber where i got the manual from this from, but if you want, i can mail it to you. I still have it locally somewhere.

Greetz,

pSyChO dAd