[FFmpeg-devel] [PATCH 09/18] avcodec/hevcdec: Add stat_coeffs to HEVCABACState

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Sat Jul 2 14:43:33 EEST 2022


Andreas Rheinhardt:
> Andreas Rheinhardt:
>> Anton Khirnov:
>> c) The current state of affairs is btw weird: Given that the secondary
>> HEVCContexts are overwritten by the main HEVCContext in
>> hls_slice_data_wpp, the rice state that every HEVCContext starts with is
>> given by the state of the first HEVCContext. And which row (of the last
>> picture) this corresponds to depends upon the number of slice threads in
>> use. This might cause problems if dependent_slice_segment_flag is enabled.
>>
> 
> kvazaar allows to create files with dependent_slice_segment_flag == 1;
> but it puts one row into one slice and so the above issue would probably
> not manifest itself. The caveat "probably" is necessary, because
> decoding such files with slice threading leads to "entry_point_offset
> table is corrupted" errors (which is probably a decoder bug).
> 

The first slice segment header of a picture has entry points for all
rows, even for those that are actually in other slice segments. I don't
know whether this is how it is supposed to be.

- Andreas


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