How to extract AAC audio out of MP4

[DRP]

I've got this MP4 file which I want to convert to DVD. I've read some guides and searched the forums, but been unsuccessful so far in finding an answer that works. The MP4 contains as far as I can tell H.264 (AVC1) video and AAC audio. I can play it on the computer perfectly well. I have CoreAVC. My main problem is getting the audio out of it. Normally I do this with GoldWave which works very well, but in this instance GoldWave doesn't recognise the audio stream. Nor can I open the mp4 in VirtualDubMod either to demux the audio stream.

I have installed and configured the latest ffdshow codec pack as per a guide I found and I can open the mp4 directly in TMPGEnc if I enable the ffdshow filters to handle it, but again the audio is proving to be a problem. How is this done?

[Baldrick]

Try demux it using yamb.

[DRP]

Yep, that worked.

Any tips on how to get the video to now open up in VDubMod for me?

[guns1inger]

Use a short avisynth script ?

DirectShowSource("pathtoyourfile\filename.mp4")

[DRP]

Brilliant. That's even better actually because I can make it use the CoreAVC codec instead which is a lot faster. That's great, thanks for the ideas guys, I'm fully sorted now. Cheers.

[DRP]

Sorry, just one last sorta related question: How can I stop AviSynth from sending the audio stream through its processing filters? I will handle the audio by other means. Is there an AviSynth command to tell it to ignore all audio streams?

[guns1inger]

DirectShowSource("pathtoyourfile\filename.mp4", audio=false)

[DRP]

Bitchin'. Ta

[gOdiSOnyOuRsIDe]

Sorry for bumping a year old thread but I would like to know how I can open .mp4 files in VirtualDubMod as well.

Where can I find/enter DirectShowSource("pathtoyourfile\filename.mp4") in VDubMod?

[Ai Haibara]

Make a text file with that line in it (be sure to change 'pathtoyourfile' to the correct path/directory your file resides in, and 'filename.mp4' to the correct name of your video), then save it under whatever name you want, with the extension .avs, and load the .avs file into VirtualDubMod as you would a video. Note that you must:

A) Have AVISynth installed.
B) Be able to play the video using DirectShow (have the proper codecs/filters installed).

Alternately, you can select Open video file... from the File menu in VirtualDubMod (or hit Ctrl-O). In the file-open dialog window that pops up, there should be a dropdown at the bottom of the window with the label Use AviSynth template. Pick 'DirectShowSource' from that list, change the 'Files of type:' dropdown above it to 'All types (*.*)', then load your MP4 as you normally would.

If you don't want to mess with AVISynth, you might take a look at one of the editors that can load and work with MP4 directly, such as AVIDemux. (Edit: Oops, forgot. If you're just looking to extract streams from an MP4, like the topic's title mentions ('How to extract AAC audio out of MP4'), you can also just demux the MP4 using YAMB.)

[gOdiSOnyOuRsIDe]

Yeah, I have CoreAVC installed along with all the other necessary directshow filters (no codec packs, installed all codecs individually).

Thank you for the pointers! Will give it a try and and report back.

*edit* YAMB deleted all my user start menu folders...

[Ai Haibara]

(reads comments on VideoHelp's Tools page for YAMB)

I apologize. I didn't know there were any issues with the most recent (beta) versions of YAMB. I haven't even used it in a long time (haven't had a need to mux/demux an MP4, for example), so I just have an older version installed on one of the systems here. Haven't tried uninstalling it, either - though now, I'm not sure I should, if I wanted to.

[gOdiSOnyOuRsIDe]

LoL, yeah I found out afterwards.

Luckily I have a Acronis image backup and could recover my start menu with a few clicks. I would've been a nightmare to recreate all my shortcuts.

[oposky2006]

well. fcp is a very professional editing software, it can surely help extract audio from your video.

[Ai Haibara]

well. fcp is a very professional editing software, it can surely help extract audio from your video.

...except you'd have to spend $1,000+ to buy Final Cut Pro (for your Mac), if you didn't already have it, when the task can be accomplished using much simpler freeware/shareware programs (on Windows, OS X or Linux).

gOdiSOnyOuRsIDe: I wonder why the YAMB devs haven't seemed to fix the problem (or mentioned it on their website)... or even pulled the beta and corrected it, as it sounds like it could be an issue with the installer. From the comments on the Tools page, it's even happened to people across more than one beta version.

The version I have was installed as part of another package, and just claims to be v2.0 (with a date of September 9, IIRC (I forgot which year )). I think I've already tried uninstalling it more than once on more than one system, so maybe it doesn't have the problem... I hope.

[gOdiSOnyOuRsIDe]

The version I have was installed as part of another package, and just claims to be v2.0 (with a date of September 9, IIRC (I forgot which year )). I think I've already tried uninstalling it more than once on more than one system, so maybe it doesn't have the problem... I hope.

It could be your start menu shortcuts are all location in the "All Users" folder and not in the "YourUserName" folder. This bug seems to only affect the "YourUserName" start menu shortcuts.

[Ai Haibara]

Oh, no, I haven't lost any of the Start menu entries/shortcuts. I'd done all of that uninstalling/reinstalling (the program that included YAMB) before I knew about the issue, though.

It might not have happened because the program may have used its own setup for installing YAMB and not YAMB's own installer, or the issue started with a later version, I don't know.