[FFmpeg-devel] [FFmpeg-soc] GSoC 2008 qualification task TS Muxer

Thorsten Jordan tjordan
Wed Mar 19 12:34:17 CET 2008

M?ns Rullg?rd schrieb:
> Baptiste Coudurier wrote:
>> Hi,
>> I don't think extracting duplicated code from mpegenc.c and mpegtsenc.c
>> is that hard. H264 muxing might be slightly harder.
> Assuming the H264 data is correctly encoded for TS muxing (i.e. has
> AUD NAL units and the like), it shouldn't be any harder to mux than
> anything else.  All that's needed is a descriptor in the PMT.  The
> PES packetisation is no different from MPEG2.
Just as reminder: you only have to handle the extra pitfalls of PAFF
encoded h264: the stream timebase is e.g. 1/25 even if there are 50
fields with PAFF, and there are 50 access units to mux. Either the
bottom fields get same pts/dts as the top fields or +1/2 frame duration
- in that case it is harder to write the muxer.
As far as I know, the two fields of a PAFF-coded frame don't need to be
consecutive in the stream, and can be mixed with other frames - so its
hard to compute PTS/DTS for a bottom field. Using the values from
av_interleaved_write_frame() or AVPacket the bottom field will get the
same PTS/DTS as the topfield.

Regards, Thorsten

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