[FFmpeg-devel] [PATCH] h264: update avctx width/height when flushing

[Andreas Cadhalpun]

On 10.06.2015 12:01, Michael Niedermayer wrote:
> On Wed, Jun 10, 2015 at 11:43:16AM +0200, Michael Niedermayer wrote:
>> On Tue, Jun 09, 2015 at 11:53:03PM +0200, Andreas Cadhalpun wrote:
>>> Inconsistencies between the dimensions of avctx and the frame can
>>> confuse API users. For example this can crash the demuxing_decoding
>>> example.
>>>
>>> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
>>> ---
>>>  libavcodec/h264.c | 4 ++++
>>>  1 file changed, 4 insertions(+)
>>>
>>> diff --git a/libavcodec/h264.c b/libavcodec/h264.c
>>> index 9a00214..d1eaa5e 100644
>>> --- a/libavcodec/h264.c
>>> +++ b/libavcodec/h264.c
>>> @@ -1757,6 +1757,8 @@ static int h264_decode_frame(AVCodecContext *avctx, void *data,
>>>              if (ret < 0)
>>>                  return ret;
>>>              *got_frame = 1;
>>> +            avctx->width  = pict->width;
>>> +            avctx->height = pict->height;
>>>          }
>>
>> iam not sure this is not breaking something, other parts of the h264
>> decoder expect this to be set relative to the last frame in coding
>> order.

If that's the case, then I think the h264 decoder should use a field
in the private H264Context for that information and not the public
fields in AVCodecContext.

>> also avctx->pix_fmt would then still potentially not match the last
>> output frame, also pix_fmt has the same problem as above

Yes, pix_fmt should also be updated. Attached patch does this, but
this caused changes in some h264 reinit fate tests. Is that a problem?

>> ive fixed one use of width/height not to depend on the AVCodecContext
>> value but a 2nd remains
> 
> actually theres more code that uses it
> ff_h264_draw_horiz_band() and its callers use h->avctx->height too

Could these be fixed to use a new H264Context field instead?

On 10.06.2015 02:25, Luca Barbato wrote:
> Would be better setting those in output_frame I think, I like the idea.

Done.

Best regards,
Andreas

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