gstreamer/gst/avi
Sebastian Dröge fedd6c2a28 avidemux: Also detect 0x000001 as H264 byte-stream start code in codec_data
This works around some AVI files storing byte-stream data in the
codec_data. The previous workaround was only checking for
0x00000001 (4 bytes) instead of 0x000001 (3 bytes).

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/1072>
2021-09-02 12:07:52 +00:00
..
avi-ids.h Fix FSF address 2012-11-04 00:07:18 +00:00
gstavi.c avi: allow per feature registration 2021-03-29 12:45:22 +02:00
gstavidemux.c avidemux: Also detect 0x000001 as H264 byte-stream start code in codec_data 2021-09-02 12:07:52 +00:00
gstavidemux.h avidemux: Ensure that raw video have properly aligned buffers 2016-11-20 13:14:08 +02:00
gstavielement.c avi: allow per feature registration 2021-03-29 12:45:22 +02:00
gstavielements.h avi: allow per feature registration 2021-03-29 12:45:22 +02:00
gstavimux.c avi: allow per feature registration 2021-03-29 12:45:22 +02:00
gstavimux.h avimux: Add support for >2 raw audio channels 2020-01-19 12:09:38 +00:00
gstavisubtitle.c avi: allow per feature registration 2021-03-29 12:45:22 +02:00
gstavisubtitle.h gst/avi/gstavisubtitle.h: Fix up IS_FOO macros, which makes gtk-doc much happier. 2008-03-11 15:18:43 +00:00
meson.build avi: allow per feature registration 2021-03-29 12:45:22 +02:00
README gst/avi/: Don't abort on out-of-memory. Use stream-nr as unsigned integer only. 2007-04-04 12:39:41 +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.