[FFmpeg-devel] [PATCH] movie video source

[Stefano Sabatini]

On date Sunday 2011-01-16 19:35:33 +0100, Stefano Sabatini encoded:
> On date Thursday 2011-01-06 22:55:18 +0100, Michael Niedermayer encoded:
> > On Thu, Jan 06, 2011 at 09:43:00PM +0100, Stefano Sabatini wrote:
> > > On date Tuesday 2011-01-04 23:48:24 +0100, Stefano Sabatini encoded:
> > > > On date Tuesday 2011-01-04 18:48:48 +0100, Nicolas George encoded:
> > > > > Le quintidi 15 niv?se, an CCXIX, Stefano Sabatini a ?crit?:
> > > > > > What do you suggest to do, to make the cmdutils.c PtsCorrectionContext
> > > > > > API public and use it (av_pts_correction_init(),
> > > > > > av_pts_correction_guess()) or to duplicate the code?
> > > > > 
> > > > > Something like that was evoked three weeks ago in the thread about the API
> > > > > example for lavfi. Since then, I thought I might try to implement it.
> > > > > 
> > > > > My idea was to add the PtsCorrectionContext structure to the end of
> > > > > AVCodecContext and add some sort of avcodec_set_stream_time_base function:
> > > > > this way, avcodec_decode_video2 would be able to use the pts and dts fields
> > > > > in AVPacket directly without depending on libavformat.
> > > > 
> > > > My idea was to implement a dumb transposition of the correct_pts API
> > > > in cmdutils.c:
> > > > 
> > > > AVPTSCorrectionContext
> > > > void av_pts_correction_init(AVPTSCorrectionContext *ctx);
> > > > int64_t av_pts_correction_guess(AVPTSCorrectionContext *ctx, int64_t pts, int64_t dts);
> > > > 
> > > > this would be defined in libavcodec/avcodec.h (as I don't see any
> > > > dependency on libavformat).
> > > 
> > > Michael? (I'm not going to even start coding if the design will be
> > > rejected).
> > 
> > What is missing primarely is that pts from the demuxer must be routed through
> > the decoders reordered_opaque. (that is current API)
> > That is needed or things plain and simple are wrong.
> > 
> > after that we are in API change land and i dont think this is a prerequesit to
> > this patch, just a nice to have.
> > 
> > The idea of putting a opaque PTSCorrectionContext in AVCodecContext and using
> > the AVPacket.pts/dts for it and exporting the resulting single
> > (stream) timestamp in AVFrame sounds very nice.
> > Why a avcodec_set_stream_time_base() would be needed is not clear to me though
> > 
> > About making the current cmdutils code public, i think Nicolas idea is much
> > nicer and simpler from a user applications point of view, of course it is more
> > work to implement though ..
> 
> Updated work in progress, I managed the PTS correction stuff the ugly
> way, simply copying all the logic from ffplay.c/cmdutils.c.
> 
> Also I'm not sure that the way movie->picref is created with
> avfilter_get_video_buffer_ref_from_arrays() is safe.

Updated with some fixes, depends on the rawdec.c patch I posted today.

Also I don't like at all the decoder_reorder_pts option as it sounds
overly complicated, and I would rather prefer an API solution (e.g. to
push the PtsCorrectionContext thing down into the library).

Nicolas, Michael, everyone... suggestions?
-- 
FFmpeg = Fierce and Foolish Most Portable Evangelical Guru