[whatwg] Timestamp from video source in order to sync (e.g. expose OGG timestamp to javascript)

Nikita Eelen neelen at amvonet.com
Mon May 17 16:00:21 PDT 2010

I think he means something similar to what QuickTime broadcaster and quicktime streaming server does with a delay on a live stream or wowza media server with flash media encoder when using h.264, unless I am misunderstanding something. Is that correct Odin? Not sure how ice cast deals with it but I bet it's a similar issue,


Sent from my iPad

On May 17, 2010, at 6:44 PM, David Singer <singer at apple.com> wrote:

> On May 17, 2010, at 14:31 , Odin Omdal Hørthe wrote:
>> Hello!
>> I filed bugs at mozilla and in chromium because I want to sync real
>> time data stream to live video. Some of them told me to send it here
>> as well. :-)
>> It's only possible to get relative playtime with html5 in javascript. I
>> want absolute timestamp that's embeded in OGG.
>> The spec only deals with relative times, and not getting out
>> information from the
>> Here's the deal:
>> I stream conferences using Ogg Theora+Vorbis using Icecast2. I have built a
>> site that shows the video and then automatically shows the slides (as PNG
>> files) as well. I use orbited (COMET) to have the server PUSH my «next»
>> presses on my keyboard.
>> The problem is that icecast does heavy buffering, and also the client, so
>> that while I switch the slides, the browser will go from slide 3 to 4 WAY
>> too early (from 10 second to 1 minute).
> Buffering should not make any difference to how far into a stream a time means.  If the transition from slide 3 to slide 4 happens at 10 minutes in, then as the presentation time ticks from 9:59 to 10:00 you should flip the slide.  It doesn't matter how much data is in any buffers, does it?
>> If I could get the timestamp OR time-since-started-sending/recording from
>> the ogg file in javascript, I'd be able to sync everything.
>> There are multiple way to sync this, may even an stream with the slide-data
>> INSIDE the ogg file, however, AFAIK there's also no way of getting out such
>> arbitrary streams.
>> (PS: I had some problems, so sorry if you get this email many times! :-S)
>> --
>> Beste helsing,
>> Odin Hørthe Omdal <odin.omdal at gmail.com>
>> http://velmont.no
> David Singer
> Multimedia and Software Standards, Apple Inc.

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