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Re: : Hi, do we have media transcode API?

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Wed, 4 Jul 2012 11:36:21 +0200
Message-ID: <CAHp8n2=5z6KgJpkqR40uXfy6KxUrDkPjHskA+ENdHcKzAQMOMg@mail.gmail.com>
To: "Sunyang (Eric)" <eric.sun@huawei.com>
Cc: Glenn Adams <glenn@skynav.com>, HTML WG <public-html@w3.org>
On Wed, Jul 4, 2012 at 11:06 AM, Sunyang (Eric) <eric.sun@huawei.com> wrote:
>
> -----ʼԭ-----
> : Silvia Pfeiffer [mailto:silviapfeiffer1@gmail.com]
> ʱ: 201274 16:39
> ռ: Glenn Adams
> : Sunyang (Eric); HTML WG
> : Re: Hi, do we have media transcode API?
>
> On Wed, Jul 4, 2012 at 10:24 AM, Glenn Adams <glenn@skynav.com> wrote:
>>
>> On Wed, Jul 4, 2012 at 1:28 AM, Silvia Pfeiffer <silviapfeiffer1@gmail.com>
>> wrote:
>>>
>>> On Wed, Jul 4, 2012 at 6:19 AM, Glenn Adams <glenn@skynav.com> wrote:
>>> >
>>> > On Tue, Jul 3, 2012 at 9:04 PM, Sunyang (Eric) <eric.sun@huawei.com>
>>> > wrote:
>>> >>
>>> >> We receive a HD mp4 video stream to <video> element, can we have a
>>> >> media
>>> >> transcode API to transcode the HD video stream to a different format
>>> >> video
>>> >> stream which fit for the Smartphone?
>>> >
>>> >
>>> > There is none defined.
>>>
>>> HTTP adaptive streaming is in the process of being standardised with
>>> the MediaSource API [1]. That will allow delivery of video to all
>>> devices, because it adapts to bandwidth and device capabilities.
>>>
>>> [1] e.g.
>>> http://updates.html5rocks.com/2011/11/Stream-video-using-the-MediaSource-API
>>
>>
>> True, but MSE does not define a media transcoding API.
>
> Indeed. :-)
> I was not answering the question but trying to address the need, which
> I understood to be providing the same content to different devices.
> This assumes you are using a Web browser on all devices and the
> devices support the same file formats.
>
> I now understand that the question is also about transcoding to a
> different file format (not just a different bitrate) and I don't think
> that is a problem that browsers should address. Could always be done
> on a server or in JavaScript, I guess.
>
> [yang] can we do it in javascript, how?

You have to implement the whole transcoding logic in JavaScript using
the MediaStream API to get the byte ranges from the original file (I
believe this is possible). It would, however, not be realistic to do
this for a mobile device. You're much better off doing this
servr-side.

Regards,
Silvia.
Received on Wednesday, 4 July 2012 09:37:09 UTC

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