[FFmpeg-devel] [PATCH 2/3] avcodec/h264: error out on ff_h264_pred_weight_table() only if strict spec compliance is requested

James Almer jamrial at gmail.com
Sat Apr 13 16:28:28 EEST 2019


On 4/13/2019 5:44 AM, Carl Eugen Hoyos wrote:
> 2019-04-10 21:47 GMT+02:00, Carl Eugen Hoyos <ceffmpeg at gmail.com>:
>> 2019-04-09 20:32 GMT+02:00, James Almer <jamrial at gmail.com>:
>>> Fixes ticket #7174.
>>>
>>> Signed-off-by: James Almer <jamrial at gmail.com>
>>> ---
>>> This makes what's essentially a non spec compliant
>>> stream decodable again with no visual artifacts, and
>>> without reintroducing the risk of overflows.
>>
>> Your patch leads to bit-exact output with the reference
>> decoder and old FFmpeg.
> 
> This is true for the original sample, the new sample
> zNqp.h264 has bit-exact output with old FFmpeg
> but not with your patch.

Where can i get this sample? Perhaps clipping the bogus value will make
it bitexact.

It would be nice to know what the reference decoder does, for that
matter. If it's bothering like us to check and handle this out of spec
values, or if they do like we used to and just pass them through.

> 
> Carl Eugen
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