indeo3: initialise pixel planes on allocation

This prevents decoder from reading garbage from it in case of errors later.
(cherry picked from commit 81064a8045028838fd32d18490034c207c8ecc06)

Fixes an invalid read on sample from CVE-2012-2804

Signed-off-by: Anton Khirnov <anton@khirnov.net>
mp3: exit on parsing error in mp_decode_frame

Properly forward mp_decode_layer3 errors, mp_decode_layer1 and
mp_decode_layer2 do not return errors.

Based on a patch by Michael Niedermayer.
(cherry picked from commit 0c03cc68386443f1e96ab6fb358220faf67cd5ff)

Signed-off-by: Anton Khirnov <anton@khirnov.net>
pthread: set the frame properties from the thread context, not user.

Right now, the frame properties are set from the user-facing
AVCodecContext before it is updated from the thread context, which is
wrong since they may be invalid or obsolete.