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Commit d485fed4 authored by Diego Biurrun's avatar Diego Biurrun
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Split general problems section into general questions and usage. 

Originally committed as revision 11614 to svn://svn.ffmpeg.org/ffmpeg/trunk
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doc/faq.texi
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...@@ -8,7 +8,56 @@ ...@@ -8,7 +8,56 @@
@end titlepage @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. @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 ...@@ -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 codecs. Please consult the supported codec list in the ffmpeg
documentation. 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? @section How do I encode single pictures to movies?
First, rename your pictures to follow a numerical sequence. First, rename your pictures to follow a numerical sequence.
...@@ -58,11 +149,6 @@ Applying that to the previous example: ...@@ -58,11 +149,6 @@ Applying that to the previous example:
Beware that there is no "jpeg" codec. Use "mjpeg" instead. 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? @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. 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 ...@@ -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 enabling AC-3, you automatically change the license of libavcodec from
LGPL to GPL. 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? @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 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 ...@@ -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}) or (@url{http://svn.mplayerhq.hu/michael/trunk/patches/bttv-comb-2.6.6.patch?view=co})
and pass 'combfilter=2'. 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. @section -f jpeg doesn't work.
Try '-f image2 test%d.jpg'. Try '-f image2 test%d.jpg'.
...@@ -147,11 +193,6 @@ 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. Some codecs, like MPEG-1/2, only allow a small number of fixed framerates.
Choose a different codec with the -vcodec command line option. 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? @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
...@@ -231,24 +272,6 @@ Just create an "input.avs" text file with this single line ... ...@@ -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/}. 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? @section How can I join video files?
A few multimedia containers (MPEG-1, MPEG-2 PS, DV) allow to join video files by 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 \ ...@@ -306,10 +329,6 @@ ffmpeg -f u16le -acodec pcm_s16le -ac 2 -ar 44100 -i all.a \
rm temp[12].[av] all.[av] rm temp[12].[av] all.[av]
@end example @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. @section FFmpeg does not adhere to the -maxrate setting, some frames are bigger than maxrate/fps.
Read the MPEG spec about video buffer verifier. Read the MPEG spec about video buffer verifier.
...@@ -330,23 +349,6 @@ examining all of the vbv_delay values and making complicated computations." ...@@ -330,23 +349,6 @@ examining all of the vbv_delay values and making complicated computations."
@chapter Development @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? @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, Yes. Read the Developers Guide of the FFmpeg documentation. Alternatively,
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