[FFmpeg-devel] [PATCH] set AVFrame decode_error_flags in case of decoding error by h264dec

[Michael Niedermayer]

On Wed, Jun 12, 2019 at 10:09:08AM +0200, Marton Balint wrote:
> 
> 
> On Wed, 12 Jun 2019, Michael Niedermayer wrote:
> 
> >On Tue, Jun 11, 2019 at 03:21:41PM -0500, Amir Z wrote:
> >>Thanks Michael Niedermayer for looking into this
> >>
> >>What I am trying to solve is having a way to detect concealed decoding
> >>errors by the caller to avcodec_receive_frame.
> >>
> >>Should I add a general value e.g. #define
> >>FF_DECODE_ERROR_DECODE_ERROR_OCCURRED 4 ?
> >
> >I suggest
> >FF_DECODE_ERROR_CONCEALMENT_ACTIVE or something similar and then always
> >set this for all cases of error concealment
> >Its more informative than just knowing there was an error
> 
> Concealment is a consequence. Error_flags should refer to the cause. A
> generic UNKNOWN error seems much better to me if it is not feasible to
> determine the cause.

Concealment is the consequence generally, still the error in the frames
differs between concealment or no concealment. A user application may
want to treat these differently.
concealemnt is not supported by all codecs currently and also not by
all variants, for example interlaced material tends to be less supported
in concealment. A user app might choose to discard a frame that
contains errors but no concealemnt if the following frame is fine.

Also in a very pedantic view, concealemnt itself is an error too.
Its rarly known exactly where the damage starts so concealment often needs
to cover more and by doing so adds errors in a minority of locations
that is if you just want a formal argument why this would fit in here.
Not an argument against the principle that concealemnt differs here in what
it is, you are certainly correct about that.

[...]
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