extract aac from ogm

[ikarishinji41]

Hi there. I've always used VirtualDubMod to extract files from OGM files. However, I got some now with the information "OGM audio stream 2 [tag 0X00FF, AAC], and I can't extract it. VirtualDubMod tells me "no audio decompressor could be found to decompress the audio format". Can anyone tell me what I should do?

[kschang]

Revised: read the next message.

[celtic_druid]

Extracting, you should be fine. Just decoding where you have problems. Audio uses ACM, not VfW and I don't think that there is any working ACM aac decompressor.

Since you want a wav, try mplayer.
mplayer.exe -ao pcm:file=audio.wav -aid 1 -vo null -vc dummy input.ogm

Think the first audio stream is 0 anyway, which makes the second 1.

[ikarishinji41]

I've installed ffdshow, but VirtualDubMod still tells me the audio stream is unknown and can't decompress. I may have configured ffdshow wrong. Could you help me again? Thanks.

[kschang]

Okay, for my curiosity: what's the difference between ACM-style... uh, filter? (that VDub uses), and just a plain DS filter, like CoreAAC?

[celtic_druid]

Different interface. ACM is the audio equiv of VfW. Doesn't handle VBR properly, etc.

The only ACM decoding ffdshow does is for MakeAVIS avi's (frameserving AVISynth scripts as avi's). Does have aac decoding (realaac or faad), just for dshow only.

So basically VfW/ACM are old and lack features needed for modern audio/video codecs. They need to die. Directshow isn't the best for editing either.

Come to think of it. AVIDemux can handle ogm's and aac. Tends to crash here though when seeking in ogm's. Haven't tried any recent builds though. Was just about to build the latest SVN rev, but it needs updating for x264's new API.

[kschang]

So the answer is: you can't use VDubMod (which uses an older interface that doesn't support the latest protocols)

EDIT: Doh! Must read in detail before posting. That's a *nix tool. :P

[celtic_druid]

If you mean AVIDemux. It is cross platform. Runs under windows to.

[ikarishinji41]

I've downloaded and run avidemux, but it doesn't seem be able to handle the two audio streams on the OGM file separately, and I want the second audio track.

[celtic_druid]

Don't get what you mean. You should get a popup when you open the file that multiple audio streams are detected. Then in the audio menu under main audio you can select the second stream.

[ikarishinji41]

Well, it worked. But now there's another problem: when I try to save the audio track, I always end up with a Okb file. The information on the OGM file says that the audio is AAC Stereo Bitrate 9303/74kbps Frequency 48000 Hz Duration 26:28:15. Any format I choose to save it in, I end up with a 0Kb file. I tried opening files that wok on VirtualDubMod, and on these I could save the audio with no problems. So, I have no idea what's going on.

[celtic_druid]

That's why I suggested mplayer way back at the start. It has always worked for me where as AVIDemux isn't exactly reliable when it comes to ogm's and aac audio isn't exactly standard, so you can't expect all tools t handle it perfectly. Personally I would use mkv or mp4 if I wanted aac audio. ogm is a dead format.

[ikarishinji41]

Well, thanks. I'm gonna try it. As for MKV, my problem with it is that I can't extract the audio, video and subtitles from it and have them match in length because the movie is variable frame rate. So, I can't build a DVD from it. I have no interest whatsoever in watching movies on my computer, that's what my TV and DVD player are for. Computer screens are WAY too small to watch a movie on. That's my problem with MKV.

[ikarishinji41]

PS.: I'd be VERY grateful if anyone could help me with this MKV problem.

[celtic_druid]

An mkv being VFR is a seperate issue. If the mkv used CFR video, then it would be no more difficult to handle than ogm. All I was saying is that if I wanted to use aac audio, I would choose mkv or mp4 as a container over ogm.

[mallorn]

Good day! I have the exact same problem as the thread starter. I've tried to use mplayer to extract the AAC and I used the command line given above but I got the following error message: -ao is not an MEncoder option. Thank you in advance for any help!

[celtic_druid]

Well the mplayer syntax has changed slightly since then, also as you will note it is an mplayer commandline, not mencoder.

Command should now be something like -ao pcm:fast -ao null -vc null

For mencoder it would be -aoc pcm, but then mencoder can't output audio only.