Re: Carriage of WebVTT in MP4

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 Thursday, 29 August 2013 13:37:58 UTC