Re: Carriage of WebVTT in MP4

Hi everyone,

Good news: Cyril wrote a blog post on MP4 encapsulation.

Have a read here:
http://www.w3.org/community/texttracks/2013/09/11/carriage-of-webvtt-and-ttml-in-mp4-files/
.

It's a good read to understand how WebVTT and TTML are encapsulated
into MP4 and what the differences are.

Cheers,
Silvia.



On Thu, Aug 29, 2013 at 11:37 PM, Cyril Concolato
<cyril.concolato@telecom-paristech.fr> wrote:
> Hi Silvia,
>
> Le 05/08/2013 13:45, Silvia Pfeiffer a écrit :
>
>> Hi Cyril,
>>
>> That's some nice work there! Great to hear you've found a good way to
>> encapsulate WebVTT into MP4. Also great to hear that you've already
>> got software support for this in mp4box and that it works with DASH!
>
> Thanks. Now that we have support for MSE in GPAC, I plan to check the
> support for text tracks in MSE. I'll let you know.
>
>
>>
>> BTW: I read back over
>> http://concolato.wp.mines-telecom.fr/2013/04/26/webvtt-in-mp4/ and the
>> slide deck there.
>
> I'm glad you read it.
>
>>   I would say that you really don't have to worry
>> about encapsulating comments or invalid cues into MP4 tracks.
>
> Sure comments and invalid cues are not so important now, but we wanted to
> have a future proof encapsulation, as in between cue text might become
> meaningful in the future, who knows. You might want to have metadata that is
> only valid after some cues.
>
>> The only
>> thing that I think you need to care about is that if you parse a
>> WebVTT file according to the WebVTT parsing algorithm and you parse
>> the re-extracted WebVTT file after its encapsulation in MP4, they
>> should result in the same information.
>
> Agree. That's what I tried to say in the slide 8.
>
>> Thus, I suggest there is no
>> need for the Additional TextBoxes that are in your slides. They
>> wouldn't be rendered anyway.
>
>
>> But that's just a suggestion. I think it all looks pretty good.
>
> Thanks for the suggestion. Since April things have evolved and the
> AdditionalTextBoxes has been accepted, but it doesn't hurt and you're not
> forced to use it anyway.
>
>>
>> (I am not convinced by how you're rendering WebVTT in GPAC by
>> converting it to SVG Tiny, but that's an orthogonal issue and a
>> technology choice that may make sense for GPAC.)
>
> Exactly, we have SVG rendering support so adding rendering for WebVTT with
> that came almost for free.
>
>
>>
>> I wonder if you'd like to write an article for
>> http://www.w3.org/community/texttracks/ about the specification of how
>> to encapsulate WebVTT in MP4 and it's implementation in MP4Box?
>
> Sure. Let me know the details in a private email.
>
> Cyril
>
>>
>> Cheers,
>> Silvia.
>>
>> On Thu, Aug 1, 2013 at 4:52 PM, Cyril Concolato
>> <cyril.concolato@telecom-paristech.fr> wrote:
>>>
>>> Dear WebVTT addicts,
>>>
>>> I have written a blog post [1] describing my implementation within the
>>> GPAC
>>> project of the carriage and playback of WebVTT content in MP4 files. I
>>> thought it would be interesting to this list. Comments are welcome.
>>>
>>> [1]
>>>
>>> http://concolato.wp.mines-telecom.fr/2013/07/28/webvtt-mp4-files-dash-and-gpac/
>>>
>>> Regards,
>>> Cyril
>>>
>>> --
>>> Cyril Concolato
>>> Maître de Conférences/Associate Professor
>>> Groupe Multimedia/Multimedia Group
>>> Telecom ParisTech
>>> 46 rue Barrault
>>> 75 013 Paris, France
>>> http://concolato.wp.mines-telecom.fr/
>>>
>>>
>
>
> --
> Cyril Concolato
> Maître de Conférences/Associate Professor
> Groupe Multimedia/Multimedia Group
> Telecom ParisTech
> 46 rue Barrault
> 75 013 Paris, France
> http://concolato.wp.mines-telecom.fr/
>
>

Received on Friday, 13 September 2013 03:50:04 UTC