[FFmpeg-devel] [PATCH] avoid crashes if input stream size changes without using -r

Måns Rullgård mans
Mon Jul 6 11:57:26 CEST 2009

Reimar D?ffinger <Reimar.Doeffinger at gmx.de> writes:

> On Mon, Jul 06, 2009 at 10:28:38AM +0100, M?ns Rullg?rd wrote:
>> Reimar D?ffinger <Reimar.Doeffinger at gmx.de> writes:
>> > On Mon, Jul 06, 2009 at 05:30:56AM +0200, Michael Niedermayer wrote:
>> >> On Sun, Jul 05, 2009 at 01:45:45PM +0200, Reimar D?ffinger wrote:
>> >> > I don't know why, but currently FFmpeg only checks for an input stream
>> >> > size change when it is using resizing.
>> >> 
>> >> id guess, the idea might have been to allow size changes on the encoder
>> >> side too when supported (trivial for intra only codecs)
>> >
>> > The code for that isn't there though (rawenc with the current code could
>> > already handle that fine), FFmpeg never gives the encoder the slightest
>> > hint that the resolution changed (avctx width/height stay at the
>> > original values)...
>> Then we should fix that.
> That would mean at the same time fixing all encoders to handle it or
> there will still be crashes.


> Also, while the raw "encoder" can handle size changes, the result won't
> be usable in most containers (which containers that handle raw can
> handle mid-stream size changes in it?).
> That's why I proposed the error message, making size changes without
> scaling work right is more than a small effort and will probably only
> work for a select few formats anyway.
> It might make more sense to just require an explicit codec re-init in
> that case

Then ffmpeg.c should do that re-init.

> (though that still doesn't answer how to handle it at the muxer
> level).

Add an AVFMT_* flag.

M?ns Rullg?rd
mans at mansr.com

More information about the ffmpeg-devel mailing list