[mythtv-users] Problem using ffmpeg to transcode a DVB-T recording

Nick Rout nick at rout.co.nz
Sun Jul 3 18:16:30 EDT 2005


I think you need to be looking at the -map: option for ffmpeg, although
from the documentation I can't figure out exactly how to use it.

http://ffmpeg.sourceforge.net/ffmpeg-doc.html

On Sun,  3 Jul 2005 14:28:21 +0100
Mike Ryan wrote:

> Hi
> 
> I use ffmpeg to transcode my dvb-t recordings to watch on a PSP and I'm in the
> UK. Everything works fine apart from anything I record from Channel 4. For some
> reason, there is no sound when I play it back on the PSP. I believe the problem
> is that ffmpeg seems to think there's two sound channels - it's selecting the
> primary one. Playback on MythTV is no problem. Here's a sample of the output
> from
> ffmpeg:
> 
> ffmpeg version 0.4.9-pre1, build 4756, Copyright (c) 2000-2004 Fabrice Bellard
>   configuration:  --enable-faac
>   built on Jun 17 2005 16:02:27, gcc: 3.4.3 20050227 (Red Hat 3.4.3-22.fc3)
> Input #0, mpeg, from
> '/mythtv/recordings/1008_20050630200000_20050630210000.nuv':
>   Duration: 00:59:55.1, start: 1697.474022, bitrate: 2893 kb/s
>   Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 704x576, 25.00 fps, 10000 kb/s
>   Stream #0.1[0x1c1]: Audio: mp2, 48000 Hz, mono, 64 kb/s
>   Stream #0.2[0x1c0]: Audio: mp2, 48000 Hz, stereo, 192 kb/s
> Output #0, psp, to '/mythtv/video/M4V10003.MP4':
>   Stream #0.0: Video: mpeg4, yuv420p, 320x240, 29.97 fps, q=2-31, 512 kb/s
>   Stream #0.1: Audio: aac, 24000 Hz, stereo, 32 kb/s
> Stream mapping:
>   Stream #0.0 -> #0.0
>   Stream #0.1 -> #0.1
> 
> For any other channel, the larger bitrate audio channel comes first, ie:
> Input #0, mpeg, from
> '/mythtv/recordings/1073_20050628191500_20050628195800.nuv':
>   Duration: 00:42:54.5, start: 16393.593167, bitrate: 3053 kb/s
>   Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576, 25.00 fps, 15000 kb/s
>   Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, stereo, 256 kb/s
>   Stream #0.2[0x1c1]: Audio: mp2, 48000 Hz, mono, 56 kb/s
> 
> Any got any ideas how I either
> 1: Tell ffmpeg to select the second audio input channel
> or
> 2: Get myth to record with the larger audio channel first (if this makes sense)
> 
> Thanks in advance for any help
> 
> Regards
> 
> Mike
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

-- 
Nick Rout



More information about the mythtv-users mailing list