gstreamer/gst/avi
Ronald S. Bultje 38946080fd New typefind system: bytestream is now part of the core all plugins have been modified to use this new typefind syste...
Original commit message from CVS:
New typefind system:
* bytestream is now part of the core
* all plugins have been modified to use this new typefind system
* asf typefinding added
* mpeg video stream typefiding removed because it's broken
* duplicate typefind entries removed
* extra id3 typefinding added, because we've seen 4 types of files
(riff/wav, flac, vorbis, mp3) with id3 headers and each of these needs
to work. Instead, I've added an id3 element and let it redo typefiding
after the id3 header. this needs a hack because spider only typefinds
once. We can remove this hack once spider supports multiple typefinds.
* with all this, mp3 typefinding is semi-rewritten
* id3 typefinding in flac/vorbis is removed, it's no longer needed
* fixed spider and gst-typefind to use this, too.
* Other general cleanups
2003-10-01 13:14:52 +00:00
..
.gitignore Initial revision 2001-12-22 23:22:30 +00:00
gstavidecoder.c api change 2002-10-02 08:05:23 +00:00
gstavidemux.c New typefind system: bytestream is now part of the core all plugins have been modified to use this new typefind syste... 2003-10-01 13:14:52 +00:00
gstavidemux.h New typefind system: bytestream is now part of the core all plugins have been modified to use this new typefind syste... 2003-10-01 13:14:52 +00:00
gstavimux.c Set keyframe flag only when it is a keyframe. This will break quite some formats because many encoders dont set this ... 2003-09-30 21:06:43 +00:00
gstavimux.h This fixes avimux largely. Sound playback still isn't optimal, but at least we're getting somewhere 2003-06-01 12:23:46 +00:00
Makefile.am Remove all locally-defined optimization flags 2003-09-11 19:57:59 +00:00
README Initial revision 2001-12-22 23:22:30 +00:00

The avi decoder plugins 
-----------------------

The avi decoder consists of a set of gstreamer plugins:

 - demuxer (avidemux)
 - avi to gstreamer type converter (avitypes)
 - windows dlls wrappers.

the avidecoder element uses the above plugins to perform the avi
decoding. It is constructed as a custom bin which initially only has
the demuxer element in it. The demuxer has a set of padtemplates for
raw audio and video.

  (------------------------------------)
  ! avidecoder                         !
  !                                 (video/raw)...
  !     (----------)                   !
  !     ! demuxer (video/avi, auds)..  !
  !     !          !                   !
  !   -src         !                   !
  !  /  !         (video/avi, vids)..  !
 - src  !          !                   !
  !     (----------)                (audio/raw)...
  !                                    !
  (------------------------------------)

the demuxer has a set of padtemplates for the raw avi header properties.

The avi decoder will act on the new_pad signal of the demuxer element
and will attach an avitype plugin to the new pad. Caps negotiation will
convert the raw avi caps to the gstreamer caps. If the src pad of the
avitypes plugin are compatible with the avidecoder padtemplate, the 
avitype pad is ghosted to the avidecoder bin, this is the case where no
codec is needed (for raw PCM samples, for example).

When the avitypes caps are not compatible with one of the avidecoder 
templates, a static autoplugger is used the find an element to connect
the demuxers pad to the decoders padtemplate.

When no element could be found, an windec plugin is attached to the 
demuxers pad and the avitypes plugin is removed from the decoder.


example:
--------

 An avidecoder that has a video pad (decoded with windows dlls) and an
 audio pad (raw PCM).

  (----------------------------------------------------------------)
  ! avidecoder               (--------)    (------)                !
  !                          !avitypes!    !windec!       /-- (video/raw)
  !     (----------)     /-sink      src--sink   src -----         !
  !     !demuxer (video/avi, !        !    !      !                !
  !     !          ! auds).. (--------)    (------)                !  
  !   -sink        !         (--------)                            !
  !  /  !        (video/avi, !avitypes!                            !
 -sink  !          ! vids).. !        !                            !
  !     (----------)     \-sink      src -------------------- (audio/raw)
  !                          (--------)                            !
  (----------------------------------------------------------------)



TODO
----

automatically generate the padtemplates from all possible avi types
found in the registry.