HACKING: Add some basic documentation on how our wrapping works.

HACKING: Add some basic documentation on how our wrapping works.

Original commit message from CVS:
* HACKING:
Add some basic documentation on how our wrapping works.
* TODO:
Add a list of things that could be worked on or that need doing.
* configure.ac:
Update snapshot.
* ext/ffmpeg/Makefile.am:
Changne .la links. See below (autotools patch).
* ext/ffmpeg/gstffmpeg.c: (plugin_init):
Enable demuxers. See below (gstffmpegdemux.c).
* ext/ffmpeg/gstffmpegcodecmap.c: (gst_ffmpeg_formatid_to_caps):
Realmedia caused a crash - fix that.
* ext/ffmpeg/gstffmpegdemux.c: (gst_ffmpegdemux_averror),
(gst_ffmpegdemux_base_init), (gst_ffmpegdemux_init),
(gst_ffmpegdemux_close), (gst_ffmpegdemux_dispose),
(gst_ffmpegdemux_stream_from_pad),
(gst_ffmpegdemux_src_event_mask), (gst_ffmpegdemux_src_event),
(gst_ffmpegdemux_src_format_list),
(gst_ffmpegdemux_src_query_list), (gst_ffmpegdemux_src_query),
(gst_ffmpegdemux_src_convert), (gst_ffmpegdemux_add),
(gst_ffmpegdemux_open), (gst_ffmpegdemux_loop),
(gst_ffmpegdemux_change_state), (gst_ffmpegdemux_register):
Right. OK, so I fixed up the demuxing and have it basically-working,
and the best way to get some more people to test it is to actually
enable it. I'm not sure if we want this for 0.8.0, but we can at
least give it a try. I've tested avi, matroska and mpeg, all appear
to work. The cool thing is that this gives us instant support for
several exotic formats that we'd never care about ourselves. Again,
this needs more testing for it to still be enabled in 0.8.0, but I
want to give it a try...
* ext/ffmpeg/gstffmpegmux.c: (gst_ffmpegmux_base_init),
(gst_ffmpegmux_init), (gst_ffmpegmux_request_new_pad),
(gst_ffmpegmux_connect), (gst_ffmpegmux_loop),
(gst_ffmpegmux_register):
Add some fixups that I use locally. Make it work in the case of
MPEG encoding, but the muxer is still not in shape to be enabled.
* ext/ffmpeg/gstffmpegprotocol.c: (gst_ffmpegdata_open),
(gst_ffmpegdata_read), (gst_ffmpegdata_write),
(gst_ffmpegdata_seek), (gst_ffmpegdata_close):
Some small fixups that crept into it while it was disabled for the
last few years. Basically works.
* gst-libs/ext/ffmpeg/Makefile.am:
Instead of having our local-autotoolized version, I patch the ffmpeg
source to be fully autotoolized. That means a simple SUBDIRS here
is now enough.
* gst-libs/ext/ffmpeg/Tag:
Version update.
* gst-libs/ext/ffmpeg/patch/autotools.diff:
Autotoolize ffmpeg. Needs to be sent to ffmpeg-devel@...
* gst-libs/ext/ffmpeg/patch/disableinstalllibs.diff:
Don't install their libs.
* gst-libs/ext/ffmpeg/patch/disablemmx.diff:
Don't use MMX. It cannot ocmpile using PIC.
* gst-libs/ext/ffmpeg/patch/disabletools.diff:
Don't compile/install their tools, we don't use them.
* gst-libs/ext/ffmpeg/patch/functions.diff:
Prevent symbol conflicts.
* gst-libs/ext/ffmpeg/patch/matroska.diff:
Add a matroska demuxer. Needs to be sent to ffmpeg-devel@...