[FFmpeg-devel] first experience with ffmpeg

[D. Hugh Redelmeier]

| From: Stefano Sabatini <stefano.sabatini-lala at poste.it>
| >     $ ffmpeg -v 9 -ss 00:23:44 -t 00:09:15 -i 2008.02.11-19.28.wma don.mp3
| >     FFmpeg version SVN-r8876, Copyright (c) 2000-2007 Fabrice Bellard, et al.
|                      ^^^^^^^^^
| >       configuration: --prefix=/usr --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --extra-cflags=-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic --enable-libmp3lame --enable-libogg --enable-libtheora --enable-libvorbis --enable-libfaad --enable-libfaac --enable-libgsm --enable-xvid --enable-x264 --enable-liba52 --enable-liba52bin --enable-libdts --enable-pp --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-opts --disable-strip
| >       libavutil version: 49.4.0
| >       libavcodec version: 51.40.4
| >       libavformat version: 51.12.1
| >       built on May  3 2007 12:41:19, gcc: 4.1.2 20070424 (Red Hat 4.1.2-11)
| 
| Really ancient version acccording to the ffmpeg standards. Retry with
| the newest and greatest, maybe that has been fixed.

OK.  I've done these tests with a newer version:
 FFmpeg version SVN-r11518, Copyright (c) 2000-2008 Fabrice Bellard, et al.
  configuration: --prefix=/usr --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --extra-cflags=-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic --enable-libdc1394 --enable-liba52 --enable-libfaac --enable-libfaad --enable-libgsm --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libxvid --enable-libx264 --enable-pp --enable-swscaler --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-optimizations --disable-strip
  libavutil version: 49.6.0
  libavcodec version: 51.49.0
  libavformat version: 52.3.0
  libavdevice version: 52.0.0
  built on Feb 16 2008 17:54:52, gcc: 4.1.2 20070925 (Red Hat 4.1.2-27)

I got this version as a Source RPM from livna's development repository.
With a bit of playing around, I got it to build and install on my
Fedora 7 x86_64 system.

Thanks, Rathann, for maintaining these rpms on Livna and for helping
me on #livna.

===> Rathann: would you consider moving these from development to
     testing?

I've done some testing.  Some things worked better.  For example, the
time-based extraction from the raw captured file worked.  Last time, a
"null transcode" (-acodec copy) needed to be done first to have this work.

But after a time-based extraction (-ss and -t), the Play Duration and
Send Duration tags, as reported by exiftool, are wrong.  This confuses
my Zen V -- it thinks that the file contains 0 seconds of material.
It can play them but fast forward does not work.

If I subject the extracted file to a null transformation, the
Durations are corrected.  Then the file works properly on the Zen V.

This seems like a bug in ffmpeg.

===> extraction should result in a file with correct Durations.  Null
     transcoding should not be required.

I did a little bit of experimenting.  The -album flag did not seem to
make a difference in the .wma file.  At least not one that exiftool
detected.  -author and -title did.  Is this just the nature of .wma /
.asf?

===> -album ought to be fixed for .wma / .asf OR documented in the
     manpage as not being applicable