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Chromecast does not handle segmented WebVTT correctly #417

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
What steps will reproduce the problem?
1. Tell a custom receiver to play a HLS stream with segmented WebVTT subtitles.

What is the expected output? What do you see instead?
Subtitles that exist in two segments are displayed twice. They should only be 
displayed once. They work fine on both AppleTV and iOS devices.

What version of the product are you using? On what operating system?
Chromecast with Mediaplayer library 1.0.

Please provide any additional information below.
The stream below exhibits the error several times, beginning at 1:05.

http://csm-e.cds1.yospace.com/csm/builder/97096051,97543813.1,93230581,97096041,
97143477,97143489,97683293,97143482,97683414,97683340,96603487,97096046,93402448
,97543813.2,93230581,97143477,97096041,97143482,97683356,97683276,96603487,97683
414,97096270,93230576,97543813.3,93230581,97096041,97143477,97683328,97683276,97
143482,96602151,97638012,97143503,97096051,93230576,97543813.4,93400750,97143477
,97096041,97403305,97683340,97143553,97683414,97143482,97683276,97683303,9709605
1,93230576,97543813.5?ref=app10-prd-cds1-85-1414508812635&f=000092731603&t=chrom
ecast.tv4play.se,N%C3%B6je,S%C3%A5%20mycket%20b%C3%A4ttre,S%C3%A5%20mycket%20b%C
3%A4ttre%20del%202,long_form,tv4play_atv,V,s%C3%A5-mycket-b%C3%A4ttre,orups-dag&
s=TV4Play/N%C3%B6je/S%C3%A5%20mycket%20b%C3%A4ttre&yo.ns=true&yo.sl=3&yo.dp=true

Original issue reported on code.google.com by erik.mid...@gmail.com on 29 Oct 2014 at 8:21

GoogleCodeExporter commented 9 years ago 
Can you provide a new stream? The provided stream doesn't work at all in our 
tests.

Original comment by christia...@google.com on 29 Oct 2014 at 5:03

GoogleCodeExporter commented 9 years ago

Original comment by christia...@google.com on 29 Oct 2014 at 5:12

GoogleCodeExporter commented 9 years ago 
This url should work: 
http://papi.tv4play.se//playback/hls/hlsproxy.m3u8?hlsurl=http%3A%2F%2Ftv4play3-
vh.akamaihd.net%2Fi%2Fmp4root%2F2014-10-24%2Fpid4971646(2998129_%2CT3MP4130%2CT3
MP43%2CT3MP48%2CT3MP415%2CT3MP425%2CT3MP435%2CT3MP445%2C).mp4.csmil%2Fmaster.m3u
8%3Fb%3D1400-%26__b__%3D4500&subsurl=http%3A%2F%2Fiosv.tv4play.se%2Fsubs%2F2014-
10-24%2Fvid_2998129%2Fprog_index.m3u8%3F&retail=false&user_state=premium

Original comment by erik.mid...@gmail.com on 30 Oct 2014 at 9:19

GoogleCodeExporter commented 9 years ago 
I'm not seeing duplicated captions with the second repro stream you provided.  
Could you please double-check that you're using MPL 1.0?  It has code to deal 
specifically with this issue.

Original comment by vadi...@chromium.org on 31 Oct 2014 at 6:05

GoogleCodeExporter commented 9 years ago 
That's really odd. I'm sure we use 1.0, as you can see here: 
view-source:https://chromecast.tv4play.se/index.html

Original comment by erik.mid...@gmail.com on 3 Nov 2014 at 10:16

GoogleCodeExporter commented 9 years ago 
Could you please attach a picture of when this repros using the stream in #3?  
And also let us know the currentTime of the media element of when this happens.

Original comment by vadi...@chromium.org on 3 Nov 2014 at 5:11

GoogleCodeExporter commented 9 years ago 
Sorry for the confusion - I have a new url. I tried just now, and it played 
fine in Quicktime where I got no duplicate subtitles, while on the Chromecast I 
did get duplicates. You can see an example at 3:16. 

http://csm-e.cds1.yospace.com/csm/builder/95550408,97900689.1,93230581,98227476,
98227427,98228043,97143522,98227442,98227402,98274398,98250420,98227422,98308757
,98227635,98227964,95550403,93230576,97900689.2,93230581,98227452,98227397,98227
402,96039008,98227649,98274398,98227432,98308757,98227427,98228316,98227582,9825
0420,95550408,93230576,97900689.3,93230581,96038897,97143496,98308757,98227422,9
8274398,98227447,98227427,98227402,98227674,98227635,98228043,98250420,98227397,
98228097,95550408,93230576,97900689.4?ref=app8-prd-cds1-3723038-1415096233177&f=
000092731603&t=chromecast.tv4play.se,Nöje,Bonde söker fru,Bonde söker fru 
del 6,long_form,tv4play_googlecast,IX&s=TV4Play/Nöje/Bonde söker fru

Original comment by erik.mid...@gmail.com on 4 Nov 2014 at 10:22

GoogleCodeExporter commented 9 years ago 
Attaching screenshot as well. Please note that we adjust the time display to 
get rid of a short preroll-sequence - the actual time is 3:16, not 3:09.

Original comment by erik.mid...@gmail.com on 4 Nov 2014 at 10:26

Attachments:

GoogleCodeExporter commented 9 years ago 
Thank you for providing a repro stream! The issue is caused by an extra new 
line at the end of the VTT file that MPL's webvtt parser treats as being part 
of the cue, e.g.

"4
00:00:19.760 --> 00:00:23.640 line:92%
Det var det finaste
jag fått på länge.
"

This makes it not match the text of the first cue of the next VTT file where it 
parses the new line as being part of the cue separator.

As a potential work around, if the last new line was eliminated from the VTT 
file, it would make things work as expected.

This should be fixed in the next MPL update.

Original comment by vadi...@google.com on 4 Nov 2014 at 9:03

GoogleCodeExporter commented 9 years ago 
Excellent, good work finding the problem! We will try to get rid of the extra 
new line, but if the supplier creating the streams can't do it easily it's very 
good to know that you are fixing it in the media player lib.

Original comment by erik.mid...@gmail.com on 5 Nov 2014 at 7:13

GoogleCodeExporter commented 9 years ago 
Follow up question: any idea on when a new release of the media player library 
will be available?

Original comment by erik.mid...@gmail.com on 6 Nov 2014 at 8:54

GoogleCodeExporter commented 9 years ago 
Any news regarding date for a new release of the media player library? We would 
be extreamly grateful for any information regarding this.

Original comment by Liselott...@tv4.se on 20 Nov 2014 at 11:05

GoogleCodeExporter commented 9 years ago 
Our stream supplier asks if the Chromecast VTT parser would parse the subtitles 
correctly if an additional new line were added to the end of the VTT file? If 
so, it would be a quick workaround for them.

Original comment by erik.mid...@gmail.com on 21 Nov 2014 at 9:09

GoogleCodeExporter commented 9 years ago 
The new release is now available. For the list of changes, please refer to this 
page: https://developers.google.com/cast/docs/release-notes

Original comment by christia...@google.com on 2 Dec 2014 at 7:27