Mac OS desktop Safari compatibility

[phloxic]

@mangui - First off: congrats! Very exciting.

Now the bad news ;-) Mac OS Safari's MediaSource implementation is rather suboptimal. It hangs with the samples at http://dailymotion.github.io/hls.js/demo/ Some other streams make it at least to the second segment.

As I said, I presume it's Safari's MediaSource implementation, with MPEG-DASH one encounters similar 'surprises', for instance MediaSource.isTypeSupported is even less useful than canPlayType, for instance MediaSource.isTypeSupported('video/mp4; codecs="bogus"') returns true.

Not sure whether there's a way around generic hls in Safari yet (e.g. for smooth manual bit rate switching). But maybe you already have ideas.

[mangui]

for now, stick with native HLS in Safari...

debugging MediaSource on Safari is complex as we don't have access to the underlying sourcecode. the general issue with Safari and hls.js seems to be at the fragmented MP4 generation level. it looks like Safari does not like the timestamps/fragment duration provided in the fragmented MP4 chunk.

if you dump video.buffered (click on toggle stats display) you will observe plenty of micro holes in the video buffer: :[0.0332888,0.0999121][0.1,0.1498676][0.1499111,0.1998232][0.1998666,0.2497787][0.2498222,0.3663565][0.3664,0.3996454][0.3996888,0.4662676][0.4663111,0.4995565][0.4996,0.5994676][0.5995555,0.6494232][0.6494666,0.7160454][0.7160888,0.7493343][0.7493777,0.8492454][0.8493333,0.9158676][0.9159111,0.9491565][0.9492,1.0324454][1.0324888,1.0990232]

Safari will stop the playback at the first hole...

[phloxic]

Very useful debugging interface!

With TS segment files it's slightly different, it doesn't make the jump to the first frame of the next segment, but I guess the underlying issue is more or less similar.

No rush, I was just secretly hoping for a little Safari miracle.

[domtra]

I know this issue is hard to debug but do you think it can be done? Or is there a way to prepare the ts files that these micro holes do not exist? I would really like to use your library on safari and not have to fallback on native hls. From what I found out native hls in safari does not support manual bitrate switching and that is something I definitely need. Or do you know of another way to achieve manual bitrate switching?

Thanks for the great library btw. :+1:

[mangui]

thanks @domtra. the issue should deal with the remuxing process, fmp4 box duration, maybe some rounding or timescale issues ... but without any access to Safari source code, it is hard to understand what is going on. at that stage the only way to move forward would be to get some help/hints from the Safari team. if anybody knows somebody there ... it could help !

[phloxic]

A 'brutal' alternative would be to use Dash in Safari ;-) But even then it would be extremely brittle, latest dash.js works - or rather happens to work - with Safari 9 (not 8), and only with certain segmentation methods ...

[domtra]

I actually did already tried that. Not only for Safari but for all browsers. However, their manual bitrate switching has a much bigger lag that hls.js. They always wait for the buffered content to have been played back completely before switching streams. This is unfortunately not acceptable either and is mainly the reason why I ended up using hls.js.

[AxelDelmas]

Is it possible to filter out Safari in the isSupported method? It sems that adding support for Safari is not trivial and that it won't happen short-term, so shouldn't isSupported reflect that?

It's a shame that we can't rely on MediaSource.isTypeSupported, is there any easy way to do it? Apart from parsing the UA?

[phloxic]

Some news about Safari 9:

• MediaSource.isTypeSupported behaves slightly better now, in the sense that it reports false for bogus codecs. Still, this does not help here.
• weird: the 'holes' are clearly noticeable in native HLS playback fullscreen, and even when segmenting has been done by the Apple mediafilesegmenter and validates 100% with their mediastreamvalidator: http://flowplayer.blacktrash.org/test/videotag-segmenter.html - on every segment transition the screen becomes white or jitters. Strangely enough this does not happen in a player wrapper: http://www.blacktrash.org/underdogma/ccc-trailer1.php
• the stream created with mediafilesegmenter plays a bit better in hls.js in the sense that it hangs later :-( - for consolation: this official Apple stream does not hls.js play at all in Safari: http://dailymotion.github.io/hls.js/demo/?src=http%3A%2F%2Fd12zt1n3pd4xhr.cloudfront.net%2Ffp%2Ftest%2Fsl.m3u8

[jernoble]

@mangui If you could provide a sample transmuxed MPEG2-TS -> ISO BMFF file, I can probably show you where the holes between samples are coming from.

[mangui]

@jernoble, thanks a lot for your proposal !

please find here the 6 appended ISO BMFF (results of the parsing of the first TS fragment of Big Buck Bunny)

audio_000.fmp4 (init segment) audio_001.fmp4 (moof) audio_002.fmp4 (mdat)

video_000.fmp4 (init segment) video_001.fmp4 (moof) video_002.fmp4 (mdat)

after appending those 6 segments, HTMLVideoElement.buffered looks like this with Safari Version 9.0.3 (10601.4.4)

media buffered : [0.03328888888888889,0.0999121111111111][0.1,0.14986766666666668][0.1499111111111111,0.19982322222222224][0.19986666666666666,0.24977877777777777][0.24982222222222222,0.3663565555555556][0.3664,0.39964544444444444][0.39968888888888887,0.4662676666666667][0.4663111111111111,0.49955655555555556][0.4996,0.5994676666666666][0.5995555555555555,0.6494232222222223][0.6494666666666666,0.7160454444444444][0.7160888888888889,0.7493343333333333][0.7493777777777778,0.8492454444444445][0.8493333333333334,0.9158676666666666][0.9159111111111111,0.9491565555555556][0.9492,1.0324454444444444][1.0324888888888888,1.0990232222222223][1.0991111111111111,1.1989343333333333][1.1990222222222222,1.2488898888888889][1.2489333333333332,1.2988454444444444][1.298888888888889,1.348801][1.3488444444444445,1.4154232222222223][1.4154666666666667,1.4487121111111112][1.4487555555555556,1.532001][1.5320444444444445,1.5985787777777778][1.5986666666666667,1.665201][1.6652444444444445,1.6984898888888889][1.6985333333333332,1.798401][1.7984888888888888,1.8650232222222223][1.8650666666666667,1.8983121111111112][1.8983555555555556,1.9982232222222223][1.9983111111111111,2.0648454444444444][2.064888888888889,2.0981343333333333][2.098177777777778,2.1980454444444444][2.1981333333333333,2.248001][2.2480444444444445,2.314623222222222][2.3146666666666667,2.347912111111111][2.3479555555555556,2.447823222222222][2.447911111111111,2.5144454444444446][2.5144888888888888,2.5477343333333335][2.5477777777777777,2.6476454444444446][2.6477333333333335,2.7142676666666667][2.714311111111111,2.7475565555555557][2.7476,2.8474676666666667][2.8475555555555556,2.914089888888889][2.9141333333333335,2.947378777777778][2.9474222222222224,3.047289888888889][3.0473777777777777,3.113912111111111][3.1139555555555556,3.147201][3.1472444444444445,3.247112111111111][3.2472,3.313734333333333][3.3137777777777777,3.347023222222222][3.3470666666666666,3.4469343333333335][3.4470222222222224,3.5135565555555557][3.5136,3.5468454444444446][3.5468888888888888,3.6467565555555557][3.6468444444444446,3.696712111111111][3.6967555555555554,3.7633343333333333][3.763377777777778,3.7966232222222223][3.796666666666667,3.846578777777778][3.8466222222222224,3.8965343333333333][3.896577777777778,3.9631565555555555][3.9632,3.9964454444444444][3.996488888888889,4.0963565555555554][4.0964,4.1962676666666665][4.196355555555556,4.2462232222222225][4.246266666666667,4.312845444444444][4.312888888888889,4.3461343333333335][4.346177777777778,4.429423222222222][4.429466666666666,4.512667666666666][4.512711111111111,4.545956555555556][4.546,4.612578777777777][4.612622222222222,4.645867666666667][4.645911111111111,4.712489888888889][4.712533333333333,4.745778777777778][4.745822222222222,4.845689888888889][4.845777777777778,4.895645444444445][4.8956888888888885,4.9622676666666665][4.962311111111111,4.995556555555556][4.9956,5.095467666666667][5.095555555555555,5.145423222222222][5.145466666666667,5.245334333333333][5.245422222222222,5.311956555555556][5.312,5.345245444444444][5.345288888888889,5.428534333333333][5.428577777777778,5.478489888888889][5.478533333333333,5.528445444444444][5.528488888888889,5.595023222222222][5.595111111111111,5.661645444444445][5.6616888888888885,5.694934333333333][5.694977777777778,5.744889888888889][5.744933333333333,5.794845444444444][5.794888888888889,5.844801][5.844844444444444,5.911423222222222][5.911466666666667,5.944712111111111][5.944755555555555,6.0446232222222225][6.044711111111111,6.111245444444444][6.111288888888889,6.1445343333333335][6.144577777777778,6.244445444444445][6.244533333333333,6.311067666666666][6.311111111111111,6.344356555555556][6.3444,6.444267666666667][6.444355555555555,6.510889888888889][6.510933333333333,6.544178777777778][6.544222222222222,6.644089888888889][6.644177777777778,6.710712111111111][6.710755555555555,6.744001][6.7440444444444445,6.7606676666666665][6.760711111111111,6.793956555555556][6.794,6.8106232222222225][6.810666666666667,6.843912111111111][6.843955555555556,6.910534333333334][6.910577777777778,6.943823222222222][6.943866666666667,7.043734333333333][7.043822222222222,7.110356555555556][7.1104,7.193601][7.193688888888889,7.260223222222222][7.260266666666666,7.293512111111111][7.293555555555556,7.393423222222222][7.393511111111111,7.460045444444445][7.4600888888888885,7.493334333333333][7.493377777777778,7.5766232222222225][7.576666666666667,7.609912111111111][7.609955555555556,7.643201][7.643244444444444,7.743112111111111][7.7432,7.809734333333333][7.809777777777778,7.8430232222222225][7.843066666666667,7.9429343333333335][7.943022222222222,8.009556555555555][8.0096,8.042845444444444][8.04288888888889,8.142756555555556][8.142844444444444,8.209378777777777][8.209422222222223,8.242667666666666][8.242711111111111,8.342578777777778][8.342666666666666,8.392534333333334][8.392577777777777,8.459156555555555][8.4592,8.492445444444444][8.49248888888889,8.592356555555556][8.592444444444444,8.658978777777778][8.659022222222223,8.692267666666666][8.692311111111112,8.792178777777778][8.792266666666666,8.858801][8.858844444444445,8.892089888888888][8.892133333333334,8.992001][8.992088888888889,9.058623222222222][9.058666666666667,9.09191211111111][9.091955555555556,9.191823222222222][9.19191111111111,9.258445444444444][9.25848888888889,9.291734333333334][9.291777777777778,9.391645444444444][9.391733333333333,9.458267666666666][9.458311111111112,9.491556555555556][9.4916,9.591467666666667][9.591555555555555,9.658089888888888][9.658133333333334,9.691378777777778][9.691422222222222,9.791289888888889][9.791377777777777,9.85791211111111][9.857955555555556,9.891201][9.891244444444444,9.99111211111111][9.9912,10.00780145351474]

[jernoble]

@mangui, thanks for the sample files. The first thing I notice is that the moov box for the video media doesn't have an edit box (edts). A common technique for moving the presentation timestamp back to 0:00 is to add an edit list with an empty edit, the duration of which matches the PTS of the first sample. For this file, the edit box should contain an edit list (elst) with a single edit of { duration:0, time:749, rate:1, fraction:0 }. This will take care of the gap at the start of the video file.

(Still looking into the rest of the gaps)

[jernoble]

So, there's not just gaps between the end of one sample and the start of the next, but also presentation time overlaps between two samples.

Here's a simplified table of presentation times for the first ~20 samples in video.fmp4, sorted in presentation order:

Format: [PTS start] + [Duration] =  [PTS end] - [next PTS start] = [overlap/gap]
 749 + 375 = 1124 - 1124 =  0
1124 + 375 = 1499 - 1499 =  0
1499 + 375 = 1874 - 1874 =  0
1874 + 374 = 2248 - 2250 = -2
2250 + 374 = 2624 - 2623 = +1
2623 + 375 = 2998 - 2998 =  0
2998 + 374 = 3372 - 3373 = -1
3373 + 375 = 3748 - 3747 = +1
3747 + 374 = 4121 - 4121 =  0
4121 + 375 = 4496 - 4497 = -1
4497 + 375 = 4872 - 4871 = +1
4871 + 374 = 5245 - 5245 =  0
5245 + 375 = 5620 - 5621 = -1
5621 + 375 = 5996 - 5995 = +1
5995 + 375 = 6370 - 6370 =  0
6370 + 375 = 6745 - 6745 =  0
6745 + 374 = 7119 - 7119 =  0
7119 + 374 = 7493 - 7493 =  0
7493 + 375 = 7868 - 7868 =  0
7868 + 375 = 8243 - 8244 = -1
8244 + 375 = 8619 - 8618 = +1
8618 + 374 = 8992 - 8993 = -1
8993 + 375 = 9368 - 9367 = +1
9367 + 374 = 9741 - 9741 =  0

I can't really discern a pattern here.

[mangui]

ok the way video sample duration was computed was incorrect, I also changed the timescale (I kept the original PES timescale, 90kHz) to avoid rounding issues I dumped similar table in JS and now I got relevant data

I am puzzled as I still get plenty of holes in video buffered.

I dumped the init segment and moof here mdat is unchanged.

[mangui]

@jernoble here is an updated screenshot and spreadsheet showing that there shouldn't be any overlap/gap the red color indicates holes location in video.buffered safari_hole.xlsx

media buffered : [0.033322222222222225,0.050001][0.05001111111111111,0.100001][0.1000111111111111,0.1666787777777778][0.1666888888888889,0.2000121111111111][0.2000222222222222,0.2500121111111111][0.2500222222222222,0.31667877777777775][0.3167,0.3500232222222222][0.3500333333333333,0.4166787777777778][0.4166888888888889,0.4500121111111111][0.4500222222222222,0.5166787777777778][0.5166888888888889,0.550001][0.5500222222222222,0.6166787777777778][0.6166888888888888,0.6500121111111111][0.6500222222222222,0.7000121111111111][0.7000222222222222,0.7666787777777778][0.7666888888888889,0.800001][0.8000222222222222,0.8666787777777778][0.8666888888888888,0.9000121111111111] ....

[mangui]

you can reproduce here it hosts latest dist of safari-fix branch

[jernoble]

@mangul, I have your safari-fix branch checked out, and I see the following at mp4-remuxer.js:234:

> samples
< Array (600) = $2
0 {size: 1044, duration: 375, cts: 749.75, flags: Object}
1 {size: 40, duration: 374.75, cts: 1875, flags: Object}
2 {size: 37, duration: 375.25, cts: 750, flags: Object}
3 {size: 37, duration: 375, cts: 0, flags: Object}
4 {size: 37, duration: 374.75, cts: 375, flags: Object}
5 {size: 8700, duration: 375.25, cts: 750, flags: Object}
6 {size: 6214, duration: 375, cts: 1125, flags: Object}
7 {size: 274, duration: 374.75, cts: 375, flags: Object}
8 {size: 5050, duration: 375.25, cts: 1500.25, flags: Object}
9 {size: 1582, duration: 375, cts: 749.75, flags: Object}
[...snip...]

Those fractional durations and cts make me very suspicious. It looks like they're getting truncated before being inserted into the trun box.

[jernoble]

And if you take those samples and run the following against them:

window.ptss = samples.map((sample, index) => { 
   var retval = {}; 
   var duration = Math.floor(sample.duration);
   retval.cts = lastCTS; lastCTS += duration;
   retval.pts = retval.cts + Math.floor(sample.cts);
   retval.duration = duration;
   retval.endPTS = retval.pts + duration;
   return retval; 
})

Then sort the result by pts, you get the following:

Array (600) = $9
0 {cts: 0, pts: 749, duration: 375, endPTS: 1124}
1 {cts: 1124, pts: 1124, duration: 375, endPTS: 1499}
2 {cts: 749, pts: 1499, duration: 375, endPTS: 1874}
3 {cts: 1499, pts: 1874, duration: 374, endPTS: 2248}
4 {cts: 375, pts: 2250, duration: 374, endPTS: 2624}
5 {cts: 1873, pts: 2623, duration: 375, endPTS: 2998}
6 {cts: 2623, pts: 2998, duration: 374, endPTS: 3372}
7 {cts: 2248, pts: 3373, duration: 375, endPTS: 3748}
8 {cts: 3747, pts: 3747, duration: 374, endPTS: 4121}
9 {cts: 3372, pts: 4121, duration: 375, endPTS: 4496}
[...snip...]

And you can see the gap between samples 3 & 4.

[mangui]

mmm i removed the scale by 4 factor, so you should not have anymore fractional values. see https://github.com/dailymotion/hls.js/commit/d80e4f620dfacc0596071aaabfa795333cab3651 what matters is what is printed on the console here: https://github.com/dailymotion/hls.js/blob/safari-fix/src/remux/mp4-remuxer.js#L265

[mangui]

all this is dumped on the console if webworker is disabled: http://streambox.fr/mse/hls.js-safari-fix/demo/?src=http%3A%2F%2Fwww.streambox.fr%2Fplaylists%2Fx36xhzz%2Fx36xhzz.m3u8&enableStreaming=true&autoRecoverError=true&enableWorker=false&levelCapping=-1&defaultAudioCodec=undefined

[Log] start,duration,end,cts (hls.js, line 7326)
[Log] 2999,1501,4500,2999 (hls.js, line 7328)
[Log] 9000,1499,10499,7500 (hls.js, line 7328)
[Log] 5999,1501,7500,3000 (hls.js, line 7328)
[Log] 4500,1499,5999,0 (hls.js, line 7328)
[Log] 7500,1500,9000,1500 (hls.js, line 7328)
[Log] 10499,1501,12000,3000 (hls.js, line 7328)
[Log] 13500,1500,15000,4500 (hls.js, line 7328)
[Log] 12000,1500,13500,1500 (hls.js, line 7328)
[Log] 18000,1500,19500,6001 (hls.js, line 7328)
[Log] 16499,1501,18000,2999 (hls.js, line 7328)
[Log] 15000,1499,16499,0 (hls.js, line 7328)
[Log] 22500,1500,24000,6001 (hls.js, line 7328)
[Log] 20999,1501,22500,2999 (hls.js, line 7328)
[Log] 19500,1499,20999,0 (hls.js, line 7328)
[Log] 25499,1501,27000,4500 (hls.js, line 7328)
[Log] 24000,1499,25499,1500 (hls.js, line 7328)
[Log] 27000,1500,28500,3000 (hls.js, line 7328)
[Log] 32999,1501,34500,7500 (hls.js, line 7328)
[Log] 29999,1501,31500,2999 (hls.js, line 7328)
[Log] 28500,1499,29999,0 (hls.js, line 7328)
[Log] 31500,1499,32999,1501 (hls.js, line 7328)
[Log] 36000,1500,37500,4500 (hls.js, line 7328)
[Log] 34500,1500,36000,1500 (hls.js, line 7328)
[Log] 41999,1500,43499,7500 (hls.js, line 7328)

[jernoble]

It looks like there's still an off-by-one error somewhere, because (after updating to your most recent commit), the result of parsing is the following:

(start pts, duration, end pts)
2999, 1501, 4500
9001, 1499, 10500
6000, 1501, 7501
4501, 1499, 6000
7500, 1500, 9000
10500, 1501, 12001
13501, 1500, 15001
12001, 1500, 13501
18002, 1500, 19502
16500, 1501, 18001
15002, 1499, 16501
22502, 1500, 24002
21000, 1501, 22501
19502, 1499, 21001
25501, 1501, 27002
24002, 1499, 25501
27001, 1500, 28501
33001, 1501, 34502
30001, 1501, 31502
28503, 1499, 30002
31503, 1499, 33002
36001, 1500, 37501
34501, 1500, 36001
42001, 1500, 43501
39000, 1501, 40501
37502, 1499, 39001
40502, 1499, 42001
47999, 1501, 49500
45001, 1500, 46501
43501, 1501, 45002

[mangui]

thanks for the feedback, regarding your last comment, how did you obtain these traces ? by adding some JS logs ? or by analyzing offline the generated MP4 trun ?

[jernoble]

Analyzing the generated trun. I think I see the problem with the gap @ 4500 -> 4501. If you look at the logs you've posted:

[Log] 2999,1501,4500,2999 (hls.js, line 7328)
[Log] 9000,1499,10499,7500 (hls.js, line 7328)
[Log] 5999,1501,7500,3000 (hls.js, line 7328)
[Log] 4500,1499,5999,0 (hls.js, line 7328)

You can derive the DTS from the first four durations:

1501 + 0 = 1501
1499 + 1501 = 3000
1501 + 3000 = 4501
1499 + 4501 = 6000

You expect the 4th (in DTS order) sample to start at 4500, but it's actually 4501.

[mangui]

@jernoble not sure to understand the link between DTS and the first four duration

the 4th sample in DTS order is the 2nd sample in PTS order. so even if it is the 4th one to be decoded, it will be the second one to be displayed. thus I would assume that we just need to ensure that its DTS in that case is less or equal than previous displayed sample (PTS + duration) (2999+1501= 4500)

we can eventually continue the discussion on skype (mangui_79)

[jernoble]

@mangui, each sample's DTS is calculated as (sum of previous durations), and it's PTS is DTS + CTO, or (sum of previous durations) + CTO. So the 4th sample's DTS is (0 + 1501 + 3000) = 4501, and because it's CTO is 0, it's PTS is also 4501.

[mangui]

Understood. I need to arrange a little bit the logic then. I will try to sort this out tomorrow. Thanks for your help !

[mangui]

there are some timestamp rounding issues with this stream, as PTS/DTS are extracted from PES (with a 90kHz clock) and the video frame rate is not always a multiple of 90kHz ... for that specific video it is 59.96 fps.

as a consequence with might have DTS delta of 1499,1500 or 1501 .... not always 1500 ... same for PTS delta.

I guess it should work better if we guarantee that :

• sample duration (DTS delta) is constant, and
• cts is always a multiple of sample duration.

for that stream this would mean sampleDuration = 1500, and cts = sampleDuration *Math.round(cts/sampleDuration);

I will try that way.

[mangui]

works better now ! http://dailymotion.github.io/hls.js/demo/ still there is this autoplay issue, I need to try out https://github.com/dailymotion/hls.js/issues/9#issuecomment-199376076

[jernoble]

Excellent!

The one remaining problem you may want to consider: if you consistently round in one direction, you will eventually lose A/V sync with the audio track. It may not be an issue in practice (if the rounding is truly random), but some streams may become un-synchronized over long durations.

[mangui]

yes, this might be an issue, I will try to see how this could be compensated.

I am also open to other options, as using constant frame duration for a whole fragment introduces other issues ( variable frame rate would be broken for example)

what I am not 100% clear is that trun specifies the decoding time and composition time offset of each sample, but it does not specify the display duration. so even if we have different sample duration value, as long as we have consistent timings (ie if we loop through samples sorted by DTS, then dts+cts is sorted by PTS), it should work and not create microholes ?

what is the underlying logic in Safari to avoid these microholes ? I had the feeling that having cts being a multiple of duration would help, but there might be another better way.

[k1ng440]

Hi, this changes made video shaky on windows 10 chrome

[whatvn]

regarding this change, I think we should provide an option to disable, enable using native HLS player on safari. On my box with newest MacOS, video is stuck, segment loaded fine but video cannot be played after a few seconds.

[k1ng440]

Hello, we are unable to play video on safari and jittery on google chrome. havent tested other browsers.

https://gist.github.com/k1ng440/082f71d4209430841fb8

[newchloe18]

I just started to experience a lot of dropped frames that I think is related to this commit https://github.com/dailymotion/hls.js/commit/ada0c8c676c22e324f3c565a7e87c0fdab3a566c. Let me know if I can help!

**hls.js demo Duration:132.04631 Buffered:[54,131.994333] Seekable:[0,132.04631] Played:[54,127.094875] Dropped Frames: 145

[mangui]

Thanks for your feedback, it looks like we need to find another way to avoid micro buffer holes in Safari ... i will rollback until we find a better way.

[mangui]

could you tell me more about the shakiness ? does it happen on fragment boundary only ? a screencast would be appreciated

[phloxic]

From here it works somewhat better, these are my, in part speculative observations with http://dailymotion.github.io/hls.js/demo/?src=http%3A%2F%2Fmedia.blacktrash.org%2Fstsp.m3u8&enableStreaming=true&autoRecoverError=true&enableWorker=true&levelCapping=-1&defaultAudioCodec=undefined

• loops at startup - once I 'help it' over the threshold it's almost there
• dropped frames
• holes are still visible, albeit less pronounced
• lower levels can hang more easily, presumably because the segments have more padding

[mangui]

I spotted a bug that could affect video playback on fragment boundary I updated the demo page, could you recheck ?

[damianmiles]

Thanks, I will ask @k1ng440 to check it.

[phloxic]

@mangui - on my side again maybe a bit better, the main problem is the actual start of playback.

[phloxic]

Quick heads up: with seekHoleNudgeDuration set to a rather high value like 0.5, I can overcome the start problem, but the odd clunky retry is noticeable.

[mangui]

Hi there, I would be interested to get some feedback on v0.6.1, as i just applied the sample duration trick for Safari only. ping @newchloe18 :-)

[ashevchenkoabz]

hls stream in desktop/mobile safari still doesn't start playing correctly. Poster image blinks few times and then stream can start playing or I need manually set time in the middle of video fragment to start playing.

Also bufferSeekOverHole and bufferStalledError error events (non-fatal) are firing.

[mangui]

yes, for stream with PTS not starting at 0 ... this trick using elst box should help deal with this

[mangui]

but plz note mobile safari does not support MSE, only desktop safari does.

[mangui]

@jernoble regarding elst box as the idea is to put first PTS back to 0, I guess by first PTS you mean Math.max(first audio PTS, first video PTS) ?

for example if I have my test video,

first video PTS/DTS:33ms/0ms
first audio PTS/DTS:10ms

I guess then that I need to offset both audio and video tracks by 33ms (converted in corresponding media track timescale) through elst right ?

[jernoble]

That math sounds right. Edit lists are a movie-level construct, so anything you add to the edit list will affect all tracks in the movie. I.e., if you are multiplexing audio and video into a single SourceBuffer, then the edit list will affect both tracks.

[quiz1991]

Hi, the edts box works perfectly to make video start on Safari. Thanks! But the video still cannot play through because of the tiny buffer holes.

And I've checked that these two requirements that you mentioned are already met: 1. sample duration (DTS delta) is constant, and 2. cts is always a multiple of sample duration.

What's your suggestion to fix the buffer holes?

[drichards]

@mangui + @jernoble I took a stab at making the edit box changes you were discussing above. It doesn't look like they made much difference on safari startup though. Maybe one or both of you could take a quick look to see if I'm doing something obviously wrong.

[cconcolato]

Edit lists are a movie-level construct, so anything you add to the edit list will affect all tracks in the movie. I.e., if you are multiplexing audio and video into a single SourceBuffer, then the edit list will affect both tracks.

Just correcting that. The edit list is a track construct. It is usually used to anchor a track on the movie timeline. In other words, if you don't play that track, that edit list has no effect.

[mangui]

Hi folks, adding edts/elst box seems to help improving playback startup on Safari you can check with your streams here http://streambox.fr/mse/hls.js-elst/demo/ feedback welcome related to https://github.com/dailymotion/hls.js/pull/553