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Re: Clarification of addSourceBuffer() method

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Mon, 20 Oct 2014 20:36:57 +1100
Message-ID: <CAHp8n2nQJ_yEdg31FyY5KhGRQr8SMU7A=1sFerqgzrPqBRNCCQ@mail.gmail.com>
To: Cyril Concolato <cyril.concolato@telecom-paristech.fr>
Cc: "<public-html-media@w3.org>" <public-html-media@w3.org>
On Mon, Oct 20, 2014 at 6:48 PM, Cyril Concolato
<cyril.concolato@telecom-paristech.fr> wrote:
> Le 20/10/2014 03:27, Silvia Pfeiffer a écrit :
>>
>> I'm just taking a look at the MSE spec (writing a book chapter about
>> it, actually).
>>
>> I'm looking at MediaSource.addSourceBuffer() which to me seems to be
>> the key method to add chunks of a media resource to a MediaSource
>> object.
>>
>> I'm reading the following in the spec:
>>
>> ``
>> addSourceBuffer
>>
>> Adds a new SourceBuffer to sourceBuffers.
>>
>> Implementations must support at least 1 MediaSource object with the
>> following SourceBuffer configurations. MediaSource objects must
>> support each of the configurations below, but they are only required
>> to support one configuration at a time. Supporting multiple
>> configurations at once or additional configurations is a quality of
>> implementation issue.
>>
>> * A single SourceBuffer with 1 audio track and/or 1 video track.
>>
>> * Two SourceBuffers with one handling a single audio track and the
>> other handling a single video track.
>> ``
>>
>> It seems that a SourceBuffer can only have either an interleaved
>> audio/video track, or just audio or just video. I'm a bit confused
>> about that, because SourceBuffer clearly talks about multiple audio
>> and video tracks, and also about text tracks.
>
> In theory, a SourceBuffer may indeed correspond to many multiplexed streams
> (audio(s)+video(s)+text track(s)+metadata track(s)). The text you quoted
> indicates minimal implementation requirements. Implementations are free to
> support more than that.

Ah thanks for clarifying.

It's still quite confusing actually. In particular the point about
returning two SourceBuffers where the return value of the method is
merely a SourceBuffer object. Can you explain how that is going to
work, too?

Thanks,
Silvia.
Received on Monday, 20 October 2014 09:37:44 UTC

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