[FFmpeg-devel] grabbing from dv1394

[Tommi Sakari Uimonen]

Hello.

I got the dv1394 grabbing working with a patch from 
http://svn.pardus.org.tr/pardus/devel/applications/multimedia/ffmpeg/files/ffmpeg-dv1394.patch

I grab with:

./ffmpeg -f dv1394 -i /dev/dv1394/0 -f avi -acodec copy -vcodec copy -y 
outfile.avi

FFmpeg version SVN-r8793, Copyright (c) 2000-2007 Fabrice Bellard, et al.
   configuration: --enable-gpl --enable-pthreads --enable-x11grab 
--enable-dc1394 --enable-liba52 --enable-liba52bin --enable-libdts 
--enable-libfaac --enable-libfaad --enable-libfaadbin --enable-libmp3lame 
--enable-libogg --enable-libtheora --enable-libvorbis --enable-xvid
   libavutil version: 49.4.0
   libavcodec version: 51.40.4
   libavformat version: 51.12.1
   built on Apr 27 2007 00:03:12, gcc: 4.1.2 20060928 (prerelease) (Ubuntu 
4.1.1-13ubuntu5)


(I have ffmpeg globally installed also and that does not handle dv1394 
grabbing, being an ubuntu package)

Now the problem is that the output has glitches every now and then; seems 
like some frames are skipped and some parts are recorded twice (like 
jumping half a second forward/back in the stream) and some frames are not 
entirely correct - they contain parts from other frames.

dvgrab however works just fine, so it's not a hardware problem

My machine is fast enough to handle the processing (Core2Duo), ffmpeg was 
using about 45% CPU with copying the streams, and about 80% with encoding 
on the fly to mpeg4. So the framedropping shouldn't be caused by slow 
computer.

I have also tried to pipe dvgrab output to ffmpeg, but never figured out 
the right way to do it. I tried for instance

dvgrab --format dv1 - | ffmpeg -i - -acodec copy -sameq -y outfile.avi

but I got 'pipe:: could not find codec parameters' error.


Anyone experiencing the same?

Tommi