No Audio w/ mp4a

[cjoshuav]

I downloaded some MPEG-4 videos from the Prelinger archive (the highest rez ones), and am not getting audio. The video looks great, cheesey haircuts aside.

The audio codec is mp4a.
Operating system: Vista 64-bit, all current updates

Any suggestions?

[jeroensky]

M4a is a extension. it means: Advanced audio coding audio only with no drm in a mp4 container.

So i guess you mean the AAC (Advanced Audio Coding) codec /mp4a in vlc.

I have no problems with playing my *.m4a files (aac/16bit/2.0 & 5.1/48KHz) on vista 64bit (uptodate, without the crap) & vlc 1.0.2 32bit

[cjoshuav]

Here's the full info:

Stream 1
Type: Audio
Codec: mp4a
Lang: English
Channels: Stereo
Sample Rate: 44100 Hz
AAC extension: SBR

[VLC_help]

Can you share us a sample file?

[cjoshuav]

Here's a link

[VLC_help]

You also get

faad warning: Unexpected channel configuration change
faad warning: Unexpected channel configuration change

messages to message log (Tools -> Messages... set Verbosity to 2) when you play the file?

[Lotesdelere]

Yep I got these messages as well but I wonder why since it's a stereo audio track.

MPlayer is playing it but with a lot of repeatitions as if it was jumping back every 5 seconds or so. It's playing fine in MPC-HC with the internal built-in decoder though and also in WMP using CoreAAC.
To demux and remux the file with MP4Box didn't help so I guess there is something unusual in this audio track.

[cybmole]

i had a lot of trouble recently with a similar issue - look for thread "no audio in m4a" for fixes & explanations, or search for m4b - I think mine is the only thread with that in title

[VLC_help]

Then it must be bug in FAAD decoder.

[cybmole]

Then it must be bug in FAAD decoder.

in my case - everything worked when FAAD was forced into use. I had to untick option to use system codecs & remove quicktime from preferred list.

[TheSa|nt]

I am resurecting this only because it's the first thing that comes up on Google...so best to have an up-to-date strategy.

For those having issues with AAC audio (or "MP4a" audio streams within videos)...


Go to Tools -> Preferences -> (show all) -> Audio/Codex -> Scroll down to "Preferred decoders list" and make sure "quicktime" isn't listed. If so...get rid of it. That's one of the biggest problems with VLC and AAC (or MP4a).