[FFmpeg-devel] [PATCH] avcodec/jpeg2000dec: support of 2 fields in 1 AVPacket

[Tomas Härdin]

mån 2024-02-19 klockan 00:43 +0100 skrev Marton Balint:
> 
> 
> On Fri, 16 Feb 2024, Anton Khirnov wrote:
> 
> > Quoting Tomas Härdin (2024-02-03 20:58:20)
> > > I think people with knowledge how interlacing is handled in other
> > > formats and codecs might want to chime in.
> > 
> > For MPEG codecs our decoders always output (properly signalled)
> > interlaced content as two interleaved fields in a single AVFrame
> > flagged
> > with AV_FRAME_FLAG_INTERLACED. Its height is the height of the
> > whole
> > frame, so double the number of lines in each field.
> > 
> > So IIUC this patch is taking the correct approach.
> 
> I believe interlaced HEVC has the same issue, the decoder generates
> field 
> pictures and not frames. Would changing the HEVC decoder be
> acceptable to 
> generate frames with interleaved fields?

This isn't a J2K thing, but an MXF thing. The same issue will arise for
MJPEG and raw video in MXF using SEPARATE_FIELDS.

/Tomas