anm: Get rid of some very silly goto statements
Add informative messages to av_log_ask_for_sample calls lacking them
dsputil: convert remaining functions to use ptrdiff_t strides

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
matroskadec: request a read buffer for the wav header

Solve an infiniloop.

CC: libav-stable@libav.org