(As for qtype, this is only used by the postproc video filter.)

All that code boiled down to selecting MPEG2 vs normal mode by the
postproc video filter. Now that libavcodec does not provide the data
anymore, the code had no more effects.

(This datum was only used by postproc anyway.)

macosx: re-write and simplify the apple event handlers for GetURL and OpenURL, make it respect 'macosx-autoplay' (close #6319)

There may be more I forgot about..

This is necessary to compile with libav.git HEAD or with contribs.
Streaming output still needs fixing.

Note that the input coded buffer is now only freed if the decoding
returns a decoded frame, or the buffer has been entirely consumed
(see *pp_block = NULL).

If the user explicitly asks for a filter, it's an error to not be able
to instatiate it.
This reverts commit 7b0761c4.

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

This is not supported in libavcodec anymore.

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>