demux_mov fails on framed audio codecs with constant framesize

[richardv@…]

I've uploaded a sample clip to
ftp.mplayerhq.hu/MPlayer/incoming/silent-mp4/silent-mp4.mp4

This file contains a silent audio stream. This is special because all of
the AAC frames are 7 bytes long, which means that rather than there
being a sample length table, trak -> samplesize is set to 7.

The demuxer then complains 'WARNING! Samplesize(7) != 1', and only a
small number of the frames are actually passed to the codec. Although
this more-or-less works in mplayer, mencoder fares much less well. For
instance,

mencoder -oac copy -ovc copy silent-mp4.mp4 -o silent-mp4.avi

produces a file with a corrupt video stream.

[richardv@…]

Proposed fix

[richardv@…]

Here's a patch which fixes this. It just makes sure that such files are
handled in the way mp4 audio is normally handled - by building an index
for the audio frames.