A_AAC/MPEG4/LC/SBR ... say what?

[jedhonx]

A_AAC/MPEG4/LC/SBR <-- i'm lost with this audio compressor. i don't even know if it's *.aac or *.mp4 or whatnot.

Here's my dilemma, i've got MKVs that i've managed to demux into 1 video file and 2 audio files by Vdubmod. Now, I can't seem to find any codec/converter that would allow me to convert this A_AAC/MPEG4/LC/SBR type of audio file into a usable dvd audio file (be it *.wav or *.mp2 or *.mpa).

I check out the audio file's properties in Explorer only to find out it had the wrong length compared to the video length. The MKV plays well on MPC, no hang-ups whatsoever, both audio tracks are played well too.

But whenever I extract the audio files, I just can't seem to convert them (tried using dBpowerAMP and CCE SP Trial) to something I can use to author a DVD.

Help?

[guns1inger]

I don't know how you thought CCE SP could help - it sucks at audio. If you have Quicktime Pro you can probably load the AAC files in and save wav files out.

[celtic_druid]

QT, including Pro can't handle he aac, so it would decode without the SBR part, assuming that VDubMod actually managed to extract a working aac file.

As the popup when you first run it states, VDubMod's mkv support is out of date. I would suggest using mkvextract for demuxing streams instead.

Different length audio/video suggests that the mkv contained VFR video.

[NormaJ]

Once you have properly demuxed your aac stream(s), you may want to try avi2wav or aacdecdrop to convert it to an usable dvd audio file.

Here are the downloads:
For Avi2wav:
http://www.matroska.info/

For Aacdecdrop:
http://www.rarewares.org/aac.html

[dude112]

QT, including Pro can't handle he aac, so it would decode without the SBR part, assuming that VDubMod actually managed to extract a working aac file.

As the popup when you first run it states, VDubMod's mkv support is out of date. I would suggest using mkvextract for demuxing streams instead.

Different length audio/video suggests that the mkv contained VFR video.

if the lengths are different, does that mean there's not much to do about it?

[celtic_druid]

No. You could look at the time code file and then encode in sections. So encode the 29.97fps section at 29.97fps, encode the 23.976fps section at 23.976fps, then run a 3:2 pulldown and join. That is assuming it is 23.976 and 29.97fps. Same principal for different frame rates though.

[Sakuya]

If I have an MP4 video file (not an MKV), is it possible that the video file can have 2 audio streams, one in AC3 and the other in MP3, just like how an MKV can have 2 audio streams?

If so, how can I extract one of the streams, let's say the AC3 one, so that I can playback on the DVD player?

[redwudz]

Sakuya, try dropping it into VirtualDub Mod and see if it will let you select the stream you want. If you don't find AC3, you can always save it out a a WAV and use ffmpeggui to convert to AC3. This works well with MP3 VBR audio also.

[Sakuya]

It doesn't support the MP4 format. The AC3 is in 5.1 so I can't extract it as a wave either. [/list]

[celtic_druid]

AC3 in mp4 is highly unlikely. Since mp4 doesn't support AC3, it would need to be stored as a private stream. To extract it the app would need to know how it was stored, which there are no specs for. Everyone could store it differently. If you want 5.1 sound, you should stick with aac.