[FFmpeg-devel] [PATCH] avformat/matroskaenc: always reserve max aac private data

[John Stebbins]

On Fri, 2020-05-01 at 20:28 +0200, Nicolas George wrote:
> John Stebbins (12020-05-01):
> > Well, current code in aac_adtstoasc silently ignores any
> > changes.  It
> > only generates extradata from the initial packet.  It's not checked
> > in
> > subsequent packets.
> > 
> > So this would have to be "fixed" in aac_adtstoasc as well if you
> > want
> > to add error logging.
> 
> Probably. I want to emphasize that bugs in our current code cannot be
> considered precedent to accept similar bugs in new code.
> 
> > This is also a bit beyond my expertise.  I don't know what would
> > constitute incompitible parameters beyond a few obvious
> > things.  I'm
> > not well versed in aac details.
> 
> Then for now, I would say that we can only accept when it is
> bit-identical with the extradata already there. If we cannot test for
> compatibility more finely, then we have to assume incompatibility and
> reject every AV_PKT_DATA_NEW_EXTRADATA with an error.
> 
> 

Seems reasonable.  To be clear, this should result in an error returned
up the call stack (i.e. av_interleaved_write_frame would ultimately
return an error), and an error log?