[FFmpeg-devel] [PATCH] Only output necessary NAL units in H.264 extradata in SDP

Martin Storsjö martin
Fri Apr 3 18:25:06 CEST 2009


As noted by another user a month ago 
the SDP data generated by ffmpeg for H.264 streams doesn't work with 
QuickTime Player. I'm not sure if this is a change in recent versions of 
QuickTime or a regression in ffmpeg, though.

QuickTime seems to dislike that the sprop-parameter-sets contains the 
version and identification output from x264 (which is a quite large chunk 
of data compared to the SPS and PPS parts). I also tested to shrink the 
amount of info output by x264 into this nal unit, but even with a minimal 
amount of data, it wouldn't play the content. Reordering the nal units (in 
x264), putting this unit as the last one, didn't help either.

The attached patch solves this in two possible ways, please comment on 
which one you find more reasonable.

One way is to output only the SPS and PPS nal types, which is the same as 
ff_isom_write_avcc does in libavformat/avc.c. The other way is to check 
the nri field, where a zero AFAIK indicates that the nal unit can be 

// Martin
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