doc: Fix best_nb_channells typo

Signed-off-by: Peter Meerwald <p.meerwald@bct-electronic.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
opt: check the return values of av_get_token for ENOMEM.
avfiltergraph: set deprecated filter_count.
lavf: make sure stream probe data gets freed.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
dfa: check for invalid access in decode_wdlt().

This can happen when the number of skipped lines is not consistent with
the number of coded lines.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
id3v2: pad the APIC packets as required by lavc.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
bmv: check for len being valid in bmv_decode_frame().

It can be 0 or -1 for invalid files, which may result in invalid memory
access.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
xmv: check audio track parameters validity.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
xmv: do not leak memory in the error paths in xmv_read_header()

CC: libav-stable@libav.org