[Bug 768460] New: dashdemux: Problems playing youtube streams

[GStreamer (GNOME Bugzilla)]

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

            Bug ID: 768460
           Summary: dashdemux: Problems playing youtube streams
    Classification: Platform
           Product: GStreamer
           Version: git master
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: Normal
         Component: gst-plugins-bad
          Assignee: gstreamer-bugs at lists.freedesktop.org
          Reporter: codebythepound at gmail.com
        QA Contact: gstreamer-bugs at lists.freedesktop.org
     GNOME version: ---

Created attachment 330919
  --> https://bugzilla.gnome.org/attachment.cgi?id=330919&action=edit
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

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).

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 seemed to get me to where the stream ought to be able to play using
gst-play-1.0 but I never see any video or hear any audio.  If I enable
GST_DEBUG=6 I see that dashdemux downloaded a single fragment from the server
but it never seems to send it on to the next filter.  It will continually
download the manifest with a small delay, re-parse it, and continue.  The
pipeline never exits the prerolling phase.

Thanks for any help you can provide.  I am happy to help implement a real
solution to these issues if you want to provide suggestions.

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