[Bug 768460] dashdemux: Problems playing youtube streams

[GStreamer (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=768460

Thiago Sousa Santos <thiagossantos at gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |thiagossantos at gmail.com

--- Comment #1 from Thiago Sousa Santos <thiagossantos at gmail.com> ---
(In reply to codebythepound from comment #0)
> Created attachment 330919 [details]
> MPD
> 
> Using source from 1.9.0.1.
> 
> Youtube uses mpeg-dash as one method to distribute its live streams, and I
> am trying to use gstreamer to play a stream directly from youtube servers. 
> Attached is part of the MPD for one of these streams.  I am assuming the MPD
> is valid.  It is from the live stream here:
> https://www.youtube.com/watch?v=njCDZWTI-xg.  Here is a link to an MPD for
> this file:
> https://manifest.googlevideo.com/api/manifest/dash/playlist_type/DVR/key/yt6/
> upn/OlXrWwK-70c/source/yt_live_broadcast/sparams/as,gcr,hfr,id,ip,ipbits,
> itag,playlist_type,requiressl,source,expire/gcr/us/signature/
> 80C14B2024BE29F75C1DBF68CDBDEF411A632D5E.
> 893DDA5444737864A0068A89270AB08F26ACF9D3/fexp/9407060,9416126,9416891,
> 9422596,9428398,9431012,9433096,9433223,9433946,9435526,9435876,9437066,
> 9437553,9437742,9439652,9440376/ip/216.228.112.21/requiressl/yes/itag/0/as/
> fmp4_audio_clear,webm_audio_clear,webm2_audio_clear,fmp4_sd_hd_clear,
> webm2_sd_hd_clear/expire/1467351997/id/njCDZWTI-xg.54/sver/3/ipbits/0/hfr/1
> 

How exactly to do you run this? I get a forbidden when trying. Is it region
restricted?

> I was hoping to get your help with several issues relating to dashdemux when
> dealing with these streams:
> 
> 1) Youtube puts the <SegmentTimeline> in the <Period> but outside of any
> <AdaptdationSet>.  I assume this means that this timeline should be valid
> for all future <SegmentList>'s.  The current parser doesn't seem to like
> this as after the SegmentList is parsed, I get the error "segment has
> neither duration nor timeline" printed from
> gst_mpdparser_parse_mult_seg_base_type_ext().
> 
> To get around this for the time being I put a huge hack in
> gst_mpdparser_parse_segment_timeline_node that will store any timelines that
> have been parsed (in these files - only one) and add them to any node that
> did not contain a timeline in the method
> gst_mpdparser_parse_mult_seg_base_type_ext().  This gets me past this
> problem for the time being, but then I ran into the next issue (which may be
> caused by doing this, I'm not sure).

This is close to the real solution. Stuff that is under the <Period> should be
considered default for their children that don't have that same node as a
child. I'd prefer here to just reference the parent's node when needed instead
of doing a copy.

> 
> 2) gst_mpd_client_get_period_index_at_time () iterates through the periods
> to try to find one that is valid for the current TOD.  The 1 period in the
> file is checked and has a correct start time, but for some reason has a
> duration of -1.  This causes the calculation to fail and return G_MAXUINT
> causing dashdemux to think there are no streams valid for the current time. 
> I'm not sure if -1 is an error or means "plays forever" - but I worked
> around this issue by checking if the duration was -1, and if so calling it a
> valid period.

This is a live stream, is it detected as such? The period duration of -1 might
just mean that it is infinite/unknown as it is live.

Would you mind sharing a GST_DEBUG=*adaptive*:6,dashdemux:6,uridownloader:6 log
of this issue? It would be easier to understand why it fails after you apply
your hack.

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