[FFmpeg-devel] how to download specific track data of a m3u8 content?

[aihua zhao]

thanks.

Yes, readahead the list is must.
but during playback, I found ffmpeg downloads each content of the list
-- av_read_frame() returns me each content with different stream_index.
I'm expecting av_read_frame() returns me the interested stream only.
I haven't found a way to do so; or said, is there ffmpeg interface to
specify a dedicate stream (stream_index) to download.

i'm looking into hls.c; there is recheck_discard_flags(), seems it is
designed to do some policy like this.
but I haven't found one top level interface of ffmpeg for it.
recheck_discard_flags() is called once only during hls_read_packet() when
c->first_packet is set  -- this flag is set in hls_read_header() only.


2016-06-28 22:22 GMT+08:00 Steven Liu <lingjiujianke at gmail.com>:

> 2016-06-28 14:26 GMT+08:00 aihua zhao <aihua.halley.zhao at gmail.com>:
>
> > Hi Experts:
> >
> > I use ffmpeg to parse/demux media content, and created a player basing on
> > it.
> >
> > here is a m3u8 content:
> >
> >
> http://asp.cntv.lxdns.com/asp/hls/main/0303000a/3/default/438eb7a818b246c187e72f1cd4e1bc4c/main.m3u8
> > <
> >
> http://asp.cntv.lxdns.com/asp/hls/main/0303000a/3/default/438eb7a818b246c187e72f1cd4e1bc4c/main.m3u8?maxbr=1200
> > >
> > there are three video track in it.
> >
> > I found all video/audio tracks are downloaded during playback, and I can
> > switch different track on the fly.
> > however, it consumes much bandwidth since all tracks are downloaded.
> >
> > even when I append bandwidth to the url; still the same result:
> >
> >
> http://asp.cntv.lxdns.com/asp/hls/main/0303000a/3/default/438eb7a818b246c187e72f1cd4e1bc4c/main.m3u8?maxbr=1200
> >
> > Is there any way to download the specified track only to save bandwidth?
> >
> > thanks
> >
>
> Hi Aihua Zhao,
>
>       If you haven't read the m3u8 file and parse the playlist, and read
> the sub m3u8 playlist, how do you get the info of the mpegts?
>
>       So it's must readahead the list and list all of the track for choose.
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