GOPchop replacement?

Rick C. Petty rick-freebsd at
Tue May 29 16:08:04 UTC 2007

On Tue, May 29, 2007 at 09:53:05AM +0200, Alexander Leidinger wrote:
> >So I use avidemux2 to mark the cut spots, save the project, and I have a
> >python program which converts avidemux2 project files into dvbcut project
> >files.  I've also been requantizing the video to DVD quality because my
> >tuner card records at broadcast quality MPEG2 (15 Mbit/s) which is too high
> >for DVD..  For this, I use another python script which uses a combination
> >of mpgtx, lame, ffmpeg, transcode, and mjpegtools and also converts the MP2
> >into AC3.
> MP2 (MPEG audio Layer 2) -> AC3?
> At which AC3 bitrate? If it is not lower than the MP2 bitrate, this  
> conversation is worthless.

Sorry-- I meant mp3, and yes it's lower (384 vs 192), and even still it
would not be worthless...  DVD players are required to support AC3, but
MP2/MP3 support is *optional*.  So if you're going for compatibility, it's
noth a worthless conversion.

> Why lame when you convert to AC3?

Not sure.  I'm using ffmpeg to do the conversion, and I took the WAV step
from another script I found online.  IIRC, I think I had A/V sync issues
unless I followed these precise steps.

> Is recode integrated into transcode/ffmpeg? If not, maybe it worth to  
> give it a try, it's a requantizer and doesn't need to decode and then  
> reencode.

AFAICT transcode does a decode/reencode and I noticed the quality loss.
Ffmpeg is supposed to be smarter about it and avoid the decode if
unnecessary, but I had A/V sync problems or DVD-player problems.  The
steps I perform seems to work for me-- from pvr500 tuner to compliant DVD
player.  YMMV,

-- Rick C. Petty

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