[FFmpeg-devel] H.264 + PAFF: BBC HD recording shows extreme interlacing artefacts

[Reinhard Nissl]

Hi,

Michael Niedermayer schrieb:

>> Another question that arises after colorspace conversion is displaying
>> or deinterlacing the fields in correct order. I was relying on
>> top_field_first but it seems that it is always zero as I cannot find any
>> reference of this frame member in h264.c. As mpeg12.c references this
>> member in mpeg_decode_picture_coding_extension() I assume that filling
>> this member is still missing in h264.c.
>>
>> The attached patch tries to address this issue. I hope it is correct.
> 
> i dont think this patch is sufficient to set top_field_first correctly
> i think it will be still wrong (=0) for all MBAFF

Well, I had a look into the spec and into h264.c and cannot find any
other variable which explicitly tells me "bottom_field_first" than
picture_structure.

I think you address the case where MbaffFrameFlag == 1 i. e. when
mb_adaptive_frame_field_flag == 1 && field_pic_flag == 0. In that case
top_field_first will be 1 due to picture_structure != PICT_BOTTOM_FIELD.

I don't know, how you came to the conclusion, that top_field_first will
be 0 in such a case.

Please enlighten me, if I'm still wrong.

Bye.
-- 
Dipl.-Inform. (FH) Reinhard Nissl
mailto:rnissl at gmx.de