gstreamer/gst/avi
Ronald S. Bultje 12e856c26d Riff, EBML, fourcc etc. work. Not fully finished, but better than what we used to have and definately worth a first b...
Original commit message from CVS:
Riff, EBML, fourcc etc. work. Not fully finished, but better than
what we used to have and definately worth a first broad testing.

I've revived rifflib. Rifflib used to be a bytestream-for-riff, which
just dup'ed bytestream. I've rewritten rifflib to be a modern riff-
chunk parser that uses bytestream fully, plus adds some extra functions
so that riff file parsing becomes extremely easy. It also contains some
small usability functions for strh/strf and metadata parsing. Note that
it doesn't use the new tagging yet, that's a TODO.

Avidemux has been rewritten to use this. I think we all agreed that
avidemux was pretty much a big mess, which is because it used all
sort of bytestream magic all around the place. It was just ugly.
This is a lot nicer, very complete and safe. I think this is far more
robust than what the old avidemux could ever have been. Of course, it
might contain bugs, please let me know.

EBML writing has also been implemented. This is useful for matroska.
I'm intending to modify avidemux (with a riffwriter) similarly. Maybe
I'll change wavparse/-enc too to use rifflib.

Lastly, several plugins have been modified to use rifflib's fourcc
parsing instead of their own. this puts fourcc parsing in one central
place, which should make it a lot simpler to add new fourccs. We might
want to move this to its own lib instead of rifflib.

Enjoy!
2003-12-07 20:00:41 +00:00
..
.gitignore Initial revision 2001-12-22 23:22:30 +00:00
avi-ids.h Riff, EBML, fourcc etc. work. Not fully finished, but better than what we used to have and definately worth a first b... 2003-12-07 20:00:41 +00:00
gstavi.c Riff, EBML, fourcc etc. work. Not fully finished, but better than what we used to have and definately worth a first b... 2003-12-07 20:00:41 +00:00
gstavidecoder.c api change 2002-10-02 08:05:23 +00:00
gstavidemux.c Riff, EBML, fourcc etc. work. Not fully finished, but better than what we used to have and definately worth a first b... 2003-12-07 20:00:41 +00:00
gstavidemux.h Riff, EBML, fourcc etc. work. Not fully finished, but better than what we used to have and definately worth a first b... 2003-12-07 20:00:41 +00:00
gstavimux.c Change everyone to video/x-msvideo 2003-11-27 21:49:39 +00:00
gstavimux.h Riff, EBML, fourcc etc. work. Not fully finished, but better than what we used to have and definately worth a first b... 2003-12-07 20:00:41 +00:00
Makefile.am Riff, EBML, fourcc etc. work. Not fully finished, but better than what we used to have and definately worth a first b... 2003-12-07 20:00:41 +00:00
README Change everyone to video/x-msvideo 2003-11-27 21:49:39 +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/x-msvideo, auds)..
  !     !          !                   !
  !   -src         !                   !
  !  /  !         (video/x-msvideo, 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/x-msvideo,    !    !      !                !
  !     !          ! auds).. (--------)    (------)                !  
  !   -sink        !         (--------)                            !
  !  /  !        (video/x-..,!avitypes!                            !
 -sink  !          ! vids).. !        !                            !
  !     (----------)     \-sink      src -------------------- (audio/raw)
  !                          (--------)                            !
  (----------------------------------------------------------------)



TODO
----

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