diff --git a/doc/faq.texi b/doc/faq.texi index 1272a78c8f..9dff3b0262 100644 --- a/doc/faq.texi +++ b/doc/faq.texi @@ -8,7 +8,56 @@ @end titlepage -@chapter General Problems +@chapter General Questions + +@section When will the next FFmpeg version be released? / Why are FFmpeg releases so few and far between? + +Like most open source projects FFmpeg suffers from a certain lack of +manpower. For this reason the developers have to prioritize the work +they do and putting out releases is not at the top of the list, fixing +bugs and reviewing patches takes precedence. Please don't complain or +request more timely and/or frequent releases unless you are willing to +help out creating them. + +@section I have a problem with an old version of FFmpeg; where should I report it? +Nowhere. Upgrade to the latest release or if there is no recent release upgrade +to Subversion HEAD. You could also try to report it. Maybe you will get lucky and +become the first person in history to get an answer different from "upgrade +to Subversion HEAD". + +@section Why doesn't FFmpeg support feature [xyz]? + +Because no one has taken on that task yet. FFmpeg development is +driven by the tasks that are important to the individual developers. +If there is a feature that is important to you, the best way to get +it implemented is to undertake the task yourself. + +@section FFmpeg does not support codec XXX. Can you include a Windows DLL loader to support it? + +No. FFmpeg only supports open source codecs. Windows DLLs are not +portable, bloated and often slow. + +@section My bugreport/mail to ffmpeg-devel/user has not received any replies. + +Likely reasons +@itemize +@item We are busy and haven't had time yet to read your report or +investigate the issue. +@item You didn't follow bugreports.html. +@item You didn't use Subversion HEAD. +@item You reported a segmentation fault without gdb output. +@item You describe a problem but not how to reproduce it. +@item It's unclear if you use ffmpeg as command line tool or use +libav* from another application. +@item You speak about a video having problems on playback but +not what you use to play it. +@item We have no faint clue what you are talking about besides +that it is related to FFmpeg. +@end 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}). @section I cannot read this file although this format seems to be supported by ffmpeg. @@ -16,6 +65,48 @@ Even if ffmpeg can read the file format, it may not support all its codecs. Please consult the supported codec list in the ffmpeg documentation. +@section Which codecs are supported by Windows? + +Windows does not support standard formats like MPEG very well, unless you +install some additional codecs + +The following list of video codecs should work on most Windows systems: +@table @option +@item msmpeg4v2 +.avi/.asf +@item msmpeg4 +.asf only +@item wmv1 +.asf only +@item wmv2 +.asf only +@item mpeg4 +only if you have some MPEG-4 codec installed like ffdshow or XviD +@item mpeg1 +.mpg only +@end table +Note, ASF files often have .wmv or .wma extensions in Windows. It should also +be mentioned that Microsoft claims a patent on the ASF format, and may sue +or threaten users who create ASF files with non-Microsoft software. It is +strongly advised to avoid ASF where possible. + +The following list of audio codecs should work on most Windows systems: +@table @option +@item adpcm_ima_wav +@item adpcm_ms +@item pcm +@item mp3 +if some MP3 codec like LAME is installed +@end table + + +@chapter Usage + +@section ffmpeg does not work; What is wrong? + +Try a '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? First, rename your pictures to follow a numerical sequence. @@ -58,11 +149,6 @@ Applying that to the previous example: Beware that there is no "jpeg" codec. Use "mjpeg" instead. -@section FFmpeg does not support codec XXX. Can you include a Windows DLL loader to support it? - -No. FFmpeg only supports open source codecs. Windows DLLs are not -portable, bloated and often slow. - @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. @@ -85,40 +171,6 @@ 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. -@section Which codecs are supported by Windows? - -Windows does not support standard formats like MPEG very well, unless you -install some additional codecs - -The following list of video codecs should work on most Windows systems: -@table @option -@item msmpeg4v2 -.avi/.asf -@item msmpeg4 -.asf only -@item wmv1 -.asf only -@item wmv2 -.asf only -@item mpeg4 -only if you have some MPEG-4 codec installed like ffdshow or XviD -@item mpeg1 -.mpg only -@end table -Note, ASF files often have .wmv or .wma extensions in Windows. It should also -be mentioned that Microsoft claims a patent on the ASF format, and may sue -or threaten users who create ASF files with non-Microsoft software. It is -strongly advised to avoid ASF where possible. - -The following list of audio codecs should work on most Windows systems: -@table @option -@item adpcm_ima_wav -@item adpcm_ms -@item pcm -@item mp3 -if some MP3 codec like LAME is installed -@end table - @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 @@ -132,12 +184,6 @@ will cause somewhat too strong filtering. A fix is to apply (@url{http://svn.mpl or (@url{http://svn.mplayerhq.hu/michael/trunk/patches/bttv-comb-2.6.6.patch?view=co}) and pass 'combfilter=2'. -@section I have a problem with an old version of ffmpeg; where should I report it? -Nowhere. Upgrade to the latest release or if there is no recent release upgrade -to Subversion HEAD. You could also try to report it. Maybe you will get lucky and -become the first person in history to get an answer different from "upgrade -to Subversion HEAD". - @section -f jpeg doesn't work. Try '-f image2 test%d.jpg'. @@ -147,11 +193,6 @@ Try '-f image2 test%d.jpg'. 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 ffmpeg does not work; What is wrong? - -Try a '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 XviD or DivX video with ffmpeg? Both XviD and DivX (version 4+) are implementations of the ISO MPEG-4 @@ -231,24 +272,6 @@ Just create an "input.avs" text file with this single line ... For ANY other help on Avisynth, please visit @url{http://www.avisynth.org/}. -@section My bugreport/mail to ffmpeg-devel/user has not received any replies. - -Likely reasons -@itemize -@item We are busy and haven't had time yet to read your report or -investigate the issue. -@item You didn't follow bugreports.html. -@item You didn't use Subversion HEAD. -@item You reported a segmentation fault without gdb output. -@item You describe a problem but not how to reproduce it. -@item It's unclear if you use ffmpeg as command line tool or use -libav* from another application. -@item You speak about a video having problems on playback but -not what you use to play it. -@item We have no faint clue what you are talking about besides -that it is related to FFmpeg. -@end itemize - @section How can I join video files? A few multimedia containers (MPEG-1, MPEG-2 PS, DV) allow to join video files by @@ -306,10 +329,6 @@ ffmpeg -f u16le -acodec pcm_s16le -ac 2 -ar 44100 -i all.a \ rm temp[12].[av] all.[av] @end example -@section Is there a forum for FFmpeg? I do not like mailing lists. - -Yes, (@url{http://dir.gmane.org/gmane.comp.video.ffmpeg.user}). - @section FFmpeg does not adhere to the -maxrate setting, some frames are bigger than maxrate/fps. Read the MPEG spec about video buffer verifier. @@ -330,23 +349,6 @@ examining all of the vbv_delay values and making complicated computations." @chapter Development -@section When will the next FFmpeg version be released? / Why are FFmpeg releases so few and far between? - -Like most open source projects FFmpeg suffers from a certain lack of -manpower. For this reason the developers have to prioritize the work -they do and putting out releases is not at the top of the list, fixing -bugs and reviewing patches takes precedence. Please don't complain or -request more timely and/or frequent releases unless you are willing to -help out creating them. - -@section Why doesn't FFmpeg support feature [xyz]? - -Because no one has taken on that task yet. FFmpeg development is -driven by the tasks that are important to the individual developers. -If there is a feature that is important to you, the best way to get -it implemented is to undertake the task yourself. - - @section Are there examples illustrating how to use the FFmpeg libraries, particularly libavcodec and libavformat? Yes. Read the Developers Guide of the FFmpeg documentation. Alternatively,