1. General Problems

1.1 ffserver doesn't not work.

ffmpeg development is now concentrated on the codec and format handling. New developments broke ffserver, so don't expect it to work correctly. If you have time and experience, please help us fix it.

1.2 I cannot read this file although this format seems to be suppored by ffmpeg.

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.

1.3 I get audio/video synchro problems when grabbing.

Currently, the grabbing stuff does not handle synchronisation correctly. You are free to correct it. It is planned to fix it ASAP.

1.4 How do I encode jpegs to another format ?

If the jpegs are named img1.jpg, img2.jpg, img3.jpg,..., use:

ffmpeg -i img%d.jpg /tmp/a.mpg

`%d' is replaced by the image number.

`img%03d.jpg' generates `img001.jpg', `img002.jpg', etc...

The same system is used for the other image formats.

1.5 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.

1.6 Why do I see a slight quality degradation with multithreaded MPEG* encoding ?

For multithreaded MPEG* encoding, the encoded slices must be independent, otherwise thread n would practically have to wait for n-1 to finish, so its quite logic that there is a small reduction of quality, this is not a bug

1.7 How can I read from the standard input or write to the standard output ?

Use `-' as filename.

1.8 Why Audio is not decoded in VOB files ?

AC3 decoding is optional as the codec is currently released under the GPL. Enable it with ./configure --enable-a52. Take care: by enabling AC3, you automatically change the license of libavcodec from LGPL to GPL.

1.9 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

`msmpeg4v2'

.avi/.asf

`msmpeg4'

.asf only

`wmv1'

.asf only

`wmv2'

.asf only

`mpeg4'

only if you have some mpeg4 codec installed like ffdshow or xvid

`mpeg1'

.mpg only

The following list of audio codecs should work on most windows systems

`adpcm_ima_wav'

`adpcm_ms'

`pcm'

`mp3'

if some mp3 codec like lame is installed

1.10 The chrominance seems to come from a different time then the luminance on bt8x8 captures on linux?

well known bug in the bt8x8 driver, for 2.4.26 theres a patch at (http://www.mplayerhq.hu/~michael/bttv-420-2.4.26.patch), i suspect that this will also apply cleanly to other 2.4 kernels

1.11 How to avoid the ugly aliassing artefacts 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 too apply (http://www.mplayerhq.hu/~michael/bttv-comb-2.4.26.patch) or (http://www.mplayerhq.hu/~michael/bttv-comb-2.6.6.patch) and pass 'combfilter=2'

1.12 I have a problem with an old version of ffmpeg, where should i report it?

1.13 -f jpeg doesnt work.

try '-f image -img jpeg test%d.jpg'

2. Development

2.1 Are there examples of use of the FFmpeg libraries libavcodec and libavformat ?

Yes. Read the Developers Guide of the FFmpeg documentation.

2.2 Can you support my C compiler XXX ?

No. Only GCC is supported. GCC is ported on most systems available and I don't see the need to pollute the source code with #ifdefs related to the compiler.

2.3 Can I use FFmpeg or libavcodec under Windows ?

Yes, but the MinGW tools must be used to compile FFmpeg. You can link the resulting DLLs with any other Windows program. Read the Native Windows Compilation section in the FFmpeg documentation to have more information.

2.4 Can you add automake, libtool or autoconf support ?

No. These tools are too blowted and they complicate the build. Moreover, since only `gcc' is supported they would add little advantages in terms of portability.

2.5 ffmpeg doesnt contain any debugging symbols ?

try ffmpeg_g, ffplay_g, ...

Table of Contents

1. General Problems

1.1 ffserver doesn't not work.
1.2 I cannot read this file although this format seems to be suppored by ffmpeg.
1.3 I get audio/video synchro problems when grabbing.
1.4 How do I encode jpegs to another format ?
1.5 FFmpeg does not support codec XXX. Can you include a Windows DLL loader to support it ?
1.6 Why do I see a slight quality degradation with multithreaded MPEG* encoding ?
1.7 How can I read from the standard input or write to the standard output ?
1.8 Why Audio is not decoded in VOB files ?
1.9 Which codecs are supported by windows ?
1.10 The chrominance seems to come from a different time then the luminance on bt8x8 captures on linux?
1.11 How to avoid the ugly aliassing artefacts in bt8x8 captures on linux?
1.12 I have a problem with an old version of ffmpeg, where should i report it?
1.13 -f jpeg doesnt work.

2. Development

2.1 Are there examples of use of the FFmpeg libraries libavcodec and libavformat ?
2.2 Can you support my C compiler XXX ?
2.3 Can I use FFmpeg or libavcodec under Windows ?
2.4 Can you add automake, libtool or autoconf support ?
2.5 ffmpeg doesnt contain any debugging symbols ?

Short Table of Contents

1. General Problems
2. Development

About this document

• 1. Section One
• 1.1 Subsection One-One
• ...
• 1.2 Subsection One-Two
• 1.2.1 Subsubsection One-Two-One
• 1.2.2 Subsubsection One-Two-Two
• 1.2.3 Subsubsection One-Two-Three     <== Current Position
• 1.2.4 Subsubsection One-Two-Four
• 1.3 Subsection One-Three
• ...
• 1.4 Subsection One-Four