Moreover FFmpeg strives to support all codecs natively.
A DLL loader is not conducive to that goal.
-@section My bugreport/mail to ffmpeg-devel/user has not received any replies.
+@section My bug report/mail to ffmpeg-devel/user has not received any replies.
Likely reasons
@itemize
@section Is there a forum for FFmpeg? I do not like mailing lists.
-Yes, (@url{http://dir.gmane.org/gmane.comp.video.ffmpeg.user}).
+You may view our mailing lists with a more forum-alike look here:
+@url{http://dir.gmane.org/gmane.comp.video.ffmpeg.user},
+but, if you post, please remember that our mailing list rules still apply there.
@section I cannot read this file although this format seems to be supported by ffmpeg.
@section Which codecs are supported by Windows?
Windows does not support standard formats like MPEG very well, unless you
-install some additional codecs
+install some additional codecs.
The following list of video codecs should work on most Windows systems:
@table @option
@item wmv2
.asf only
@item mpeg4
-only if you have some MPEG-4 codec installed like ffdshow or XviD
+Only if you have some MPEG-4 codec like ffdshow or Xvid installed.
@item mpeg1
.mpg only
@end table
@item adpcm_ima_wav
@item adpcm_ms
@item pcm
+always
@item mp3
-if some MP3 codec like LAME is installed
+If some MP3 codec like LAME is installed.
@end table
+@chapter Compilation
+
+@section @code{error: can't find a register in class 'GENERAL_REGS' while reloading 'asm'}
+
+This is a bug in gcc. Do not report it to us. Instead, please report it to
+the gcc developers. Note that we will not add workarounds for gcc bugs.
+
+Also note that (some of) the gcc developers believe this is not a bug or
+not a bug they should fix:
+@url{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11203}.
+Then again, some of them do not know the difference between an undecidable
+problem and an NP-hard problem...
+
@chapter Usage
-@section ffmpeg does not work; What is wrong?
+@section ffmpeg does not work; what is wrong?
Try a @code{make distclean} in the ffmpeg source directory before the build. If this does not help see
(@url{http://ffmpeg.org/bugreports.html}).
-@section How do I encode single pictures to movies?
+@section How do I encode single pictures into movies?
First, rename your pictures to follow a numerical sequence.
For example, img1.jpg, img2.jpg, img3.jpg,...
@file{img%03d.jpg} means the sequence @file{img001.jpg}, @file{img002.jpg}, etc...
+If you have large number of pictures to rename, you can use the
+following command to ease the burden. The command, using the bourne
+shell syntax, symbolically links all files in the current directory
+that match @code{*jpg} to the @file{/tmp} directory in the sequence of
+@file{img001.jpg}, @file{img002.jpg} and so on.
+
+@example
+ x=1; for i in *jpg; do counter=$(printf %03d $x); ln "$i" /tmp/img"$counter".jpg; x=$(($x+1)); done
+@end example
+
+If you want to sequence them by oldest modified first, substitute
+@code{$(ls -r -t *jpg)} in place of @code{*jpg}.
+
+Then run:
+
+@example
+ ffmpeg -f image2 -i /tmp/img%03d.jpg /tmp/a.mpg
+@end example
+
The same logic is used for any image format that ffmpeg reads.
@section How do I encode movie to single pictures?
Beware that there is no "jpeg" codec. Use "mjpeg" instead.
-@section I get "Unsupported codec (id=86043) for input stream #0.1". What is the problem?
-
-This is the Qcelp codec, FFmpeg has no support for that codec currently. Try mencoder/mplayer it might work.
-
@section Why do I see a slight quality degradation with multithreaded MPEG* encoding?
For multithreaded MPEG* encoding, the encoded slices must be independent,
@section How can I read from the standard input or write to the standard output?
-Use @file{-} as filename.
-
-@section Why does FFmpeg not decode audio in VOB files?
-
-The audio is AC-3 (a.k.a. A/52). AC-3 decoding is an optional component in FFmpeg
-as the component that handles AC-3 decoding is currently released under the GPL.
-Enable AC-3 decoding with @code{./configure --enable-gpl}. Take care: By
-enabling AC-3, you automatically change the license of libavcodec from
-LGPL to GPL.
+Use @file{-} as file name.
@section Why does the chrominance data seem to be sampled at a different time from the luminance data on bt8x8 captures on Linux?
This is a well-known bug in the bt8x8 driver. For 2.4.26 there is a patch at
-(@url{http://svn.mplayerhq.hu/michael/trunk/patches/bttv-420-2.4.26.patch?view=co}). This may also
+(@url{http://svn.ffmpeg.org/michael/trunk/patches/bttv-420-2.4.26.patch?view=co}). This may also
apply cleanly to other 2.4-series kernels.
@section How do I avoid the ugly aliasing artifacts in bt8x8 captures on Linux?
Pass 'combfilter=1 lumafilter=1' to the bttv driver. Note though that 'combfilter=1'
-will cause somewhat too strong filtering. A fix is to apply (@url{http://svn.mplayerhq.hu/michael/trunk/patches/bttv-comb-2.4.26.patch?view=co})
-or (@url{http://svn.mplayerhq.hu/michael/trunk/patches/bttv-comb-2.6.6.patch?view=co})
+will cause somewhat too strong filtering. A fix is to apply (@url{http://svn.ffmpeg.org/michael/trunk/patches/bttv-comb-2.4.26.patch?view=co})
+or (@url{http://svn.ffmpeg.org/michael/trunk/patches/bttv-comb-2.6.6.patch?view=co})
and pass 'combfilter=2'.
@section -f jpeg doesn't work.
Some codecs, like MPEG-1/2, only allow a small number of fixed framerates.
Choose a different codec with the -vcodec command line option.
-@section How do I encode XviD or DivX video with ffmpeg?
+@section How do I encode Xvid or DivX video with ffmpeg?
-Both XviD and DivX (version 4+) are implementations of the ISO MPEG-4
+Both Xvid and DivX (version 4+) are implementations of the ISO MPEG-4
standard (note that there are many other coding formats that use this
-same standard). Thus, use '-vcodec mpeg4' to encode these formats. The
+same standard). Thus, use '-vcodec mpeg4' to encode in these formats. The
default fourcc stored in an MPEG-4-coded file will be 'FMP4'. If you want
a different fourcc, use the '-vtag' option. E.g., '-vtag xvid' will
force the fourcc 'xvid' to be stored as the video fourcc rather than the
@item non-working stuff
B-frames
@item example command line
-ffmpeg -i input -acodec libfaac -ab 128kb -vcodec mpeg4 -b 1200kb -mbd 2 -flags +4mv+trell -aic 2 -cmp 2 -subcmp 2 -s 320x180 -title X output.mp4
+ffmpeg -i input -acodec libfaac -ab 128kb -vcodec mpeg4 -b 1200kb -mbd 2 -flags +4mv -trellis 2 -aic 2 -cmp 2 -subcmp 2 -s 320x180 -metadata title=X output.mp4
@end table
@section How do I encode videos which play on the PSP?
@item non-working stuff
B-frames
@item example command line
-ffmpeg -i input -acodec libfaac -ab 128kb -vcodec mpeg4 -b 1200kb -ar 24000 -mbd 2 -flags +4mv+trell -aic 2 -cmp 2 -subcmp 2 -s 368x192 -r 30000/1001 -title X -f psp output.mp4
+ffmpeg -i input -acodec libfaac -ab 128kb -vcodec mpeg4 -b 1200kb -ar 24000 -mbd 2 -flags +4mv -trellis 2 -aic 2 -cmp 2 -subcmp 2 -s 368x192 -r 30000/1001 -metadata title=X -f psp output.mp4
@item needed stuff for H.264
--acodec libfaac -vcodec h264 width*height<=76800 width%16=0? height%16=0? -ar 48000 -coder 1 -r 30000/1001 or 15000/1001 -f psp
+-acodec libfaac -vcodec libx264 width*height<=76800 width%16=0? height%16=0? -ar 48000 -coder 1 -r 30000/1001 or 15000/1001 -f psp
@item working stuff for H.264
title, loop filter
@item non-working stuff for H.264
CAVLC
@item example command line
-ffmpeg -i input -acodec libfaac -ab 128kb -vcodec h264 -b 1200kb -ar 48000 -mbd 2 -coder 1 -cmp 2 -subcmp 2 -s 368x192 -r 30000/1001 -title X -f psp -flags loop -trellis 2 -partitions parti4x4+parti8x8+partp4x4+partp8x8+partb8x8 output.mp4
+ffmpeg -i input -acodec libfaac -ab 128kb -vcodec libx264 -b 1200kb -ar 48000 -mbd 2 -coder 1 -cmp 2 -subcmp 2 -s 368x192 -r 30000/1001 -metadata title=X -f psp -flags loop -trellis 2 -partitions parti4x4+parti8x8+partp4x4+partp8x8+partb8x8 output.mp4
+@item higher resolution for newer PSP firmwares, width<=480, height<=272
+-vcodec libx264 -level 21 -coder 1 -f psp
+@item example command line
+ffmpeg -i input -acodec libfaac -ab 128kb -ac 2 -ar 48000 -vcodec libx264 -level 21 -b 640kb -coder 1 -f psp -flags +loop -trellis 2 -partitions +parti4x4+parti8x8+partp4x4+partp8x8+partb8x8 -g 250 -s 480x272 output.mp4
@end table
@section Which are good parameters for encoding high quality MPEG-4?
-'-mbd rd -flags +4mv+trell+aic -cmp 2 -subcmp 2 -g 300 -pass 1/2',
+'-mbd rd -flags +4mv+aic -trellis 2 -cmp 2 -subcmp 2 -g 300 -pass 1/2',
things to try: '-bf 2', '-flags qprd', '-flags mv0', '-flags skiprd'.
@section Which are good parameters for encoding high quality MPEG-1/MPEG-2?
-'-mbd rd -flags +trell -cmp 2 -subcmp 2 -g 100 -pass 1/2'
+'-mbd rd -trellis 2 -cmp 2 -subcmp 2 -g 100 -pass 1/2'
but beware the '-g 100' might cause problems with some decoders.
Things to try: '-bf 2', '-flags qprd', '-flags mv0', '-flags skiprd.
-@section Interlaced video looks very bad when encoded with ffmpeg, whats wrong?
+@section Interlaced video looks very bad when encoded with ffmpeg, what is wrong?
You should use '-flags +ilme+ildct' and maybe '-flags +alt' for interlaced
material, and try '-top 0/1' if the result looks really messed-up.
Similarly, the yuv4mpegpipe format, and the raw video, raw audio codecs also
allow concatenation, and the transcoding step is almost lossless.
+When using multiple yuv4mpegpipe(s), the first line needs to be discarded
+from all but the first stream. This can be accomplished by piping through
+@code{tail} as seen below. Note that when piping through @code{tail} you
+must use command grouping, @code{@{ ;@}}, to background properly.
For example, let's say we want to join two FLV files into an output.flv file:
ffmpeg -i input1.flv -vn -f u16le -acodec pcm_s16le -ac 2 -ar 44100 - > temp1.a < /dev/null &
ffmpeg -i input2.flv -vn -f u16le -acodec pcm_s16le -ac 2 -ar 44100 - > temp2.a < /dev/null &
ffmpeg -i input1.flv -an -f yuv4mpegpipe - > temp1.v < /dev/null &
-ffmpeg -i input2.flv -an -f yuv4mpegpipe - > temp2.v < /dev/null &
+@{ ffmpeg -i input2.flv -an -f yuv4mpegpipe - < /dev/null | tail -n +2 > temp2.v ; @} &
cat temp1.a temp2.a > all.a &
cat temp1.v temp2.v > all.v &
ffmpeg -f u16le -acodec pcm_s16le -ac 2 -ar 44100 -i all.a \
Yes. Read the Developers Guide of the FFmpeg documentation. Alternatively,
examine the source code for one of the many open source projects that
-already incorporate ffmpeg at (@url{projects.html}).
+already incorporate FFmpeg at (@url{projects.html}).
@section Can you support my C compiler XXX?
To get help and instructions for building FFmpeg under Windows, check out
the FFmpeg Windows Help Forum at
-@url{http://arrozcru.no-ip.org/ffmpeg/}.
+@url{http://ffmpeg.arrozcru.org/}.
@section Can you add automake, libtool or autoconf support?
@section Why not rewrite ffmpeg in object-oriented C++?
-ffmpeg is already organized in a highly modular manner and does not need to
+FFmpeg is already organized in a highly modular manner and does not need to
be rewritten in a formal object language. Further, many of the developers
favor straight C; it works for them. For more arguments on this matter,
read "Programming Religion" at (@url{http://www.tux.org/lkml/#s15}).
@section Why are the ffmpeg programs devoid of debugging symbols?
The build process creates ffmpeg_g, ffplay_g, etc. which contain full debug
-information. Those binaries are strip'd to create ffmpeg, ffplay, etc. If
+information. Those binaries are stripped to create ffmpeg, ffplay, etc. If
you need the debug information, used the *_g versions.
@section I do not like the LGPL, can I contribute code under the GPL instead?
Yes, as long as the code is optional and can easily and cleanly be placed
-under #ifdef CONFIG_GPL without breaking anything. So for example a new codec
-or filter would be OK under GPL while a bugfix to LGPL code would not.
+under #if CONFIG_GPL without breaking anything. So for example a new codec
+or filter would be OK under GPL while a bug fix to LGPL code would not.
@section I want to compile xyz.c alone but my compiler produced many errors.
See @url{http://www.parashift.com/c++-faq-lite/mixing-c-and-cpp.html#faq-32.3}
-@section I have a file in memory / a API different from *open/*read/ libc how do i use it with libavformat?
+@section I have a file in memory / a API different from *open/*read/ libc how do I use it with libavformat?
You have to implement a URLProtocol, see libavformat/file.c in FFmpeg
and libmpdemux/demux_lavf.c in MPlayer sources.
@section Where is the documentation about ffv1, msmpeg4, asv1, 4xm?
-see @url{http://svn.mplayerhq.hu/michael/trunk/docs/}
+see @url{http://svn.ffmpeg.org/michael/trunk/docs/}
@section How do I feed H.263-RTP (and other codecs in RTP) to libavcodec?
projects / ffmpeg / blobdiff