Merge remote-tracking branch 'qatar/master'

* qatar/master: (58 commits)
  amrnbdec: check frame size before decoding.
  cscd: use negative error values to indicate decode_init() failures.
  h264: prevent overreads in intra PCM decoding.
  FATE: do not decode audio in the nuv test.
  dxa: set audio stream time base using the sample rate
  psx-str: do not allow seeking by bytes
  asfdec: Do not set AVCodecContext.frame_size
  vqf: set packet parameters after av_new_packet()
  mpegaudiodec: use DSPUtil.butterflies_float().
  FATE: add mp3 test for sample that exhibited false overreads
  fate: add cdxl test for bit line plane arrangement
  vmnc: return error on decode_init() failure.
  libvorbis: add/update error messages
  libvorbis: use AVFifoBuffer for output packet buffer
  libvorbis: remove unneeded e_o_s check
  libvorbis: check return values for functions that can return errors
  libvorbis: use float input instead of s16
  libvorbis: do not flush libvorbis analysis if dsp state was not initialized
  libvorbis: use VBR by default, with default quality of 3
  libvorbis: fix use of minrate/maxrate AVOptions
  ...

Conflicts:
	Changelog
	doc/APIchanges
	libavcodec/avcodec.h
	libavcodec/dpxenc.c
	libavcodec/libvorbis.c
	libavcodec/vmnc.c
	libavformat/asfdec.c
	libavformat/id3v2enc.c
	libavformat/internal.h
	libavformat/mp3enc.c
	libavformat/utils.c
	libavformat/version.h
	libswscale/utils.c
	tests/fate/video.mak
	tests/ref/fate/nuv
	tests/ref/fate/prores-alpha
	tests/ref/lavf/ffm
	tests/ref/vsynth1/prores
	tests/ref/vsynth2/prores

Merged-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 34 insertions, 0 deletions

diff --git a/doc/muxers.texi b/doc/muxers.texi
index ddce0e902c..f500f0ab0e 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -370,5 +370,39 @@ Wrap around segment index once it reaches @var{limit}.
 ffmpeg -i in.mkv -c copy -map 0 -f segment -list out.list out%03d.nut
 @end example
 
+@section mp3
+
+The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and
+optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the
+@code{id3v2_version} option controls which one is used. The legacy ID3v1 tag is
+not written by default, but may be enabled with the @code{write_id3v1} option.
+
+For seekable output the muxer also writes a Xing frame at the beginning, which
+contains the number of frames in the file. It is useful for computing duration
+of VBR files.
+
+The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures
+are supplied to the muxer in form of a video stream with a single packet. There
+can be any number of those streams, each will correspond to a single APIC frame.
+The stream metadata tags @var{title} and @var{comment} map to APIC
+@var{description} and @var{picture type} respectively. See
+@url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
+
+Note that the APIC frames must be written at the beginning, so the muxer will
+buffer the audio frames until it gets all the pictures. It is therefore advised
+to provide the pictures as soon as possible to avoid excessive buffering.
+
+Examples:
+
+Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
+@example
+ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
+@end example
+
+Attach a picture to an mp3:
+@example
+ffmpeg -i input.mp3 -i cover.png -c copy -metadata:s:v title="Album cover"
+-metadata:s:v comment="Cover (Front)" out.mp3
+@end example
 
 @c man end MUXERS