Partial AC3 files from DVD2AVI corrupt?

[Brandon1984]

I am attempting to create 5.1 Audio CDs using AC3-WAV files. The problem I am running into is that I have to extract the ac3 file from the entire movie using all vob files of it. If I use only some vob files, to convert only part of a movie, then when I try to open the ac3 file I get an error message (differs between programs, usually about invalid frame). So I was just wondering if anyone has any suggestions, thanks.

-Brandon

[DSPguru]

how are you planning to create the ac3-wav files out of the ac3 source files ?

[Brandon1984]

There are a couple of different software programs that do it. You can try to find Sound Foundry's Soft Encode, which they are no longer distributing, or you can use HeadAC3he (which I just used and it worked). http://www.doom9.org/Soft21/Audio/headac3he-0.22b.rar

Just select the AC3-WAV option and it creates a wav file. Then burn the wav file onto an audio CD. Its awesome, works for DTS as well, but I haven't tried that yet.

-Brandon

[DSPguru]

in that case, you can ignore the error messages you got when openning the ac3 files. the ac3-wav will work anyhow.

[Brandon1984]

Ahhhhh, but it won't. It continues to encode the wav, but when I test it on my dvd player, it will blink dolby digital, as if its trying to read it, but will not play any audio.

[DSPguru]

weird.
if the errors only comes from the fact you extracted the ac3 from one of the in-between vobs, there shouldn't be a problem with the ac3-wav.
maybe the ac3 streams are totally corrupted ? did you try to play them with wmp ?

[Brandon1984]

I get the error corrput AC3 stream when attempting to open in heac3he and soft encode when I only extract a range from the vob files, not entire movie. I will keep messing with it though.

Also, do you know if it is any different to extract DTS tracks? I am attempting to do so from the Eagles DVD without success, it just creates a Linear PCM wav file with no audio.

[DSPguru]

try extracting the ac3/dts directly with vstrip_gui instead of dvd2avi.
btw, imho, dts won't work for you.

another thing you should know,
if your AC3 source files sample-rate is 48khz (most probably), whenever you'll play your burnt cd (out of the wav-ac3), your system will play it Slower (as 44.1khz).

may i suggest using BeSure (http://doom9.org/BeSure.html) ?

[ChristianHJW]

Load the original DVD into your drive and use Smartripper to extract the AC3 directly using its 'stream processing' feature. Select the audio stream you want and tick 'demux to extra file'.

Nice thing about this is that you can process only the one chapters you want when Smartripper is on 'movie mode' ...

[DarkAvenger]

Have you tried *decoding* the AC3, as well? If it works, then AC3-WAV target should work as well, but I heard that some SOny amps don't like AC3 at 44,1kHz. Well, I'll test it, whether I (once again :rolleyes: ) managed to break the ac3-wav target.

And yes, DVD2AVIs ac3 are not 100% correct, as sometime the stream start in the middle of a frame und usually end in the middle of a frame. But the frames in between are OK, and they should work. I'll check it out, though. If you select the AC3 target in HeadAC3he, the broken end and start frames are stripped, and you'll get a 100% OK stream. (But this should not be necessary if you use HeadAC3he to process the original source to any target.)

As DG correctly stated, the AC3 -due to lossless conversion- will play slower as "AudioCD", as the readme states, as well. So in order to get correct speed, you have to transcode it downsampled to 44,1kHz. So BeSure should work, creating DTS, or create a downsampled 6ch WAV (make sure you have NTFS..) with HeadAC3he and feed it to SoftEncode (channels will be correctly mapped automatically) creating an DD WAV.