flac: don't check the number of channels before setting the channel layout.

This is unnecessary, as ff_flac_set_channel_layout can handle any number of channels.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
flac: add channel layout masks for streams with 7 or 8 channels.

They were added to the latest FLAC specification:
https://git.xiph.org/?p=flac-website.git;a=commit;h=65c199a2

Signed-off-by: Anton Khirnov <anton@khirnov.net>
h263: remove an unused parameter from ff_h263_decode_init_vlc
h264: remove silly macros

They serve no useful purpose and wreak all kind of havoc when h264.h is
included elsewhere.
error_resilience: remove a useless if() and FIXME

pp_time is never set for h264
rv10: improve buffer size check.

Check slice count and input buffer size before constructing a possibly
invalid pointer, not after.
mpegvideo: remove an unused function parameter