Converting MPEG2 Audio from AC3 to MPEG1 Layer 2

[jrisch]

Does anyone know of any simple software to convert the audio of an MPEG2 file from AC3 to MPEG1 Layer2? I have a video player for my motorhome that only plays the sound if it is in MPEG1 Layer 2, and a lot of my MPEG2 files have the audio in AC3.

Thanks, John

[manono]

BeSweet, HeadAC3he, among others.

[jrisch]

Great, thanks.

[jrisch]

I'v looked at the two products suggested but they only seem to convert standalone audio files. My problem is that I have MPEG2 files that contain both video and audio. Gspot shows the embedded audio as being AC3. The player/recorder I want to use them in plays the video OK but no sound. It does play video and sound from its own recorded files that Gspot shows the embedded audio as being in MPEG1 Layer 2.

Any ideas, anyone?

[manono]

I'v looked at the two products suggested but they only seem to convert standalone audio files.

Well, yes and no. BeSweet can convert the audio from VOB files. If it won't handle MPG (you're not being clear because VOBs contain MPEG-2 video), then either try renaming the MPG or whatever it is to VOB, or (better, probably) demux first. You'll have to demux anyway if you intend to remux the MP2 audio along with the video back to MPG or whatever you want. As for demuxing, open the MPG or whatever it is in DGIndex and then File->Save Project and Demux Video. That's one way.

You seem to think you can take an MPG file and reconvert the audio only, without demuxing or remuxing anything, and it ain't gonna happen.

[Chris K]

You seem to think you can take an MPG file and reconvert the audio only, without demuxing or remuxing anything, and it ain't gonna happen.

You're right that the audio has to be demuxed first but decoding "is" demuxing so e.g. a FFmpeg command line like below should be able to do it in one go.

FFmpeg.exe -i "c:\source.mpg" -vcodec copy -acodec mp2 -ab 192k -ar 48k -ac 2 -f vob -y "c:\output.mpg"

FFmpeg will only pick out the left/right channels if it's 5.1 ac3 but the mentioned audio tools do the same.
If the audio is out of sync, try to add "-async 2" to the command line.

[netmask56]

You can do it in Womble MPEG Video Wizard DVD (make sure you get this one as it supports AC3 http://www.womble.com/ - download the trial. Import the mpeg2 file into the time line and under the audio tab select mpeg2, 1 or mp3 or wav as the audio. Eport to a new MPEG2 file. The video will be stream copied whilst the audio will be re encoded.

[manono]

Good one, netmask. I didn't realize Womble had that ability. And your suggestion is a good one I'm sure, Chris K, but, I for one, won't touch a CLI app if I can possibly avoid it. Perhaps jrisch feels differently.

[jrisch]

Many thanks, guys for all your help. I've tried both Womble's MPEG Video Wizard, very slick and full featured, though a bit pricey for my limited requirement, and FFmpeg. Both did the job in a single step. FFmpeg's CLI doesn't really worry me as I don't need to change all the parameters, and I can easily front-end it with Excel.

Thanks again.

Regards, jrisch