[FFmpeg-cvslog] Add support for aac streams in mp4/mov without extradata.

[Reimar Döffinger]

On Sun, Jul 10, 2011 at 07:42:15PM +0000, Carl Eugen Hoyos wrote:
> Benjamin Larsson <git <at> videolan.org> writes:
> 
> > ffmpeg | branch: master | Benjamin Larsson | Mon Jun 27 23:39:12 2011 -0700|
> > [dafaef2fe1e1af7c40adc1855547fd4cba9862a9] | committer: Alex Converse
> > 
> > Add support for aac streams in mp4/mov without extradata.
> 
> I am not sure this fixed many reported problems, I suspect one or two, but it
> already caused three users to report regressions. I had reported it to Benjamin
> before, and he said he is currently unavailable.

AFAICT:
Moving zeroing channels, sample_rate etc. from av_find_stream_info to
decoder init ends up overwriting the good values from a previous
av_find_stream_info with 0, i.e. the code is completely broken for
anyone that first does av_find_stream_info, then opens the codec and
then before decoding wants to check the stream parameters.
The safest way to fix, though hackish, is probably to move that
if (st->codec->codec_id == CODEC_ID_AAC)
block back again though as
if (st->codec->codec_id && st->extradata_size > 0) {
// We need to discard these since they can be plain wrong for
// backwards compatible HE-AAC signaling.
// But when we have no extradata we need to keep them or we can't
// play anything at all.