[Ffmpeg-devel] Interlaced decoding internals?

Baptiste Coudurier baptiste.coudurier
Tue Feb 6 11:08:20 CET 2007


Michael Niedermayer wrote:
> Hi
> On Mon, Feb 05, 2007 at 08:31:41PM +0200, Kostya wrote:
>> I'm working on adding interlaced frame support for VC-1 and
>> has some question regarding AVCodecContext internals:
>> What do avctx->interlaced_frame, avctx->top_field_first
>> and avctx->repeat_pict affect if set by decoder?
> they are not in AVCodecContext but AVFrame
> they affect display, top_field_first affects the order in which
> fields are shown, interlaced_frame affects if the frame is shown
> as frame or as 2 fields at 2 seperate times (assuming the player
> applictaion cares about the at all of course ...)

You'll laugh, what can I do if the interlaced info is in the container ?
I have some mjpeg a bottom field first, and info is in "fiel" atom.
I'll fix decoder, but I need a way to supply that info.
What do you prefer ? Adding a field to avctx ? (and we could get rid of
the -top option in ffmpeg)

>> And is it enough to set them and lavc will do the rest of work
>> or decoder also needs to output picture in standard format? 
> the decoder always outputs frames, they can either be made of 
> 2 fields (even and odd lines) or 1 frame 
> btw, can VC1 not switch interlaced coding at macroblock level
> like MPEG2, MPEG4 and H264?

Unfortunately, not JPEG.

Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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