get_channel() returns 0 on success

CC:libav-stable@libav.org

mp4 files embedding DVD subtitles do not use the same extradata format
as the rest of Libav expects. The subtitle decoder in libavcodec in
particular does not understand this format.

Convert the extradata to the vobsub .idx format. mp4 stores the palette
as binary 32 bit ints in YUV. The subtitle resolution is stored
separately in the track header, which we access through AVStream.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

Group checks into logical groups and sort alphabetically within those groups
unless checks have close coupling. Keep closely coupled checks together.

The function is assigned to a function pointer that does not have the
restrict keyword for that parameter.

This fixes compilation for MSVC builds that don't recognize "restrict",
broken since ed9625eb.

Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>

Drop non-informative _bfin suffix, rename some files for consistency with
other architectures, rename others to reflect their content.

This saves some space in configurations that do not enable hpeldsp.

The functions it contains are used from unconditionally compiled code.

This is done similarly for all other architectures.

Also add a few #endif comments.

They were marked as broken and disabled in 2009 and will never get fixed.

They were marked as broken and disabled in 2009 and will never get fixed.

Also switch from "tbl" to "tab" name suffixes.

This helps grepping for functions, among other things.