[FFmpeg-devel] understanding usage of av_compare_ts() in avformat/hlsenc

[Nicolas Martyanoff]

On 2014-07-10 01:41, Anssi Hannula wrote:
> 08.07.2014 13:19, Nicolas Martyanoff kirjoitti:
> > Hi,
> 
> Hi,
> 
> > I am currently working on improving the hlsenc muxer to support byteranges
> > (HLS version 4), and it is starting to work :) But there is a line that really
> > puzzles me:
> > 
> > 
> >     if (can_split && av_compare_ts(pkt->pts - hls->start_pts, st->time_base,
> >                                            end_pts, AV_TIME_BASE_Q) >= 0) {
> > 
> >     // libavformat/hlsenc.c 282
> > 
> > 
> > Afaik, av_compare_ts() compares two presentation timestamps with potentially
> > different time bases, and returns a value indicating if the first timestamp is
> > larger (i.e. more recent) than the second one.
> > 
> > However in this code, the first argument is the difference between two
> > presentation timestamp, i.e. a time length. I do not get how comparing a time
> > length and a presentation timestamp makes any kind of sense.
> > 
> > Does anyone know what I am missing here ?
> 
> I guess you may have gotten this already, but anyway:
> 
> The end_pts is actually a time length as well, not an actual PTS, since
> it is just (number_of_segments * length_of_segment).

Yes, I got it :) Thank you anyway.

-- 
Nicolas Martyanoff
http://wandrian.net
khaelin at gmail.com