[mythtv-users] HowTo Transcode HD5000 SD mpeg w/ ac3 audio to SD mpeg w/ stereo audio usable w/ mvpmc

[Kevin Kuphal]

bha at att.net wrote:
> I have a MythTV backend with an HD5000 tuner card recording QAM standard def 
> mpeg files. My problem is that these mpeg files have AC3 5.1 audio (mpeg format 
> info in xine says the audio format is "a52"). I use mvpmc (niffty little fanless 
> setup box http://mvpmc.org) as a MythTV Frontend, but the mvpmc can't play back 
> the AC3 audio (the video plays perfectly, but without any audio). I can't find 
> any way to configure the HD5000 to record it's mpeg files using standard audio 
> (ie not AC3). Have I missed something? Is there a way to make the backend 
> transcode the mpeg/AC3 files into mpeg/Stereo files? (Transcoding seems like a 
> lot of cycles wasted...even so, after reading the transcoding docs I'm not sure 
> how I would do it.)
>
>   
Using a transcoding profile "to MPEG-4" will result in an MPEG-4 file 
with MP3 audio.  Of course, I don't think this will help you since you 
have a MVPMC which does MPEG-2.  My suggestion would be to look into the 
operation of tools like mencoder or ffmpeg itself on "transcoding" the 
files yourself with a simple command-line script to change the audio 
from AC3 to MP2/3 leaving the video alone (if you can) or simply 
re-encoding the video along with.  This should get you an MPEG-2 file 
with MP2/3 audio.

Kevin