Re: [blink-dev] WebVTT vs TTML Features

Additionally, TTML is used in e.g. SMPTE-TT, EBU-TT, CFF-TT, SDP-US etc which I believe collectively reference all of the features in TTML.

Nigel


On 09/12/2013 19:50, "Glenn Adams" <glenn@chromium.org<mailto:glenn@chromium.org>> wrote:

I for one can't answer the question about actual use. First, TTML is designed for both interchange amongst authoring and archiving systems and for distribution between content service providers and end-user devices (browsers). In the former case, this content is generally in closed systems not exposed for examination, in the latter case, I have seen no use counter statistics gathering.

If Chrome implemented TTML support then we could add UseCounters to gather these metrics for TTML content used for distribution.

There is some possibility of gathering statistics another way, which is that I expect a TTML validator to go online at the W3C perhaps in the 1st quarter of 2014. This validator could catalog usage statistics over time and eventually provide useful frequency of use information.

It might be useful to query caption houses or large content archive maintainers (e.g., Time Warner - HBOGO, etc., Netflix, and so on) for such data.

G.



On Tue, Dec 10, 2013 at 3:43 AM, Loretta Guarino Reid <lorettaguarino@google.com<mailto:lorettaguarino@google.com>> wrote:
I'm confident that the features are in the requirements. The question is about actual use.


On Mon, Dec 9, 2013 at 11:41 AM, Glenn Adams <glenn@chromium.org<mailto:glenn@chromium.org>> wrote:

On Tue, Dec 10, 2013 at 3:37 AM, Loretta Guarino Reid <lorettaguarino@google.com<mailto:lorettaguarino@google.com>> wrote:

On Mon, Dec 9, 2013 at 6:54 AM, Nigel Megitt <nigel.megitt@bbc.co.uk<mailto:nigel.megitt@bbc.co.uk>> wrote:
>How many of these 114 features are actually in use in the wild? WebVTT
>has a strong drive to only support features that are motivated by a
>use case. If any of these features are necessary, WebVTT can be
>extended to support them. Some of them (like the 'padding' above)
>would be fixed simply by adding the feature to the list of supported
>CSS properties, which takes less than 5min to fix. It would be best
>for us to find this out before we freeze the spec. Any input on use
>cases would be welcome.

Considering the amount of scrutiny and effort that's been put into
developing TTML over many years it's safest to assume that all of the
features have a use case/requirement within the overall scope of
requirements rather than starting from the opposite perspective. Different
subsets of these features may be needed for different parts of the entire
author->audience workflow.


I would hope that the amount of scrutiny and effort that has gone in would make it easy to respond to this request, since you would know where the features are needed, hence where to look for the examples.

I would suggest folks that wish to explore this further start by reading the Timed Text Authoring Use Cases and Requirements document at [1], which served to drive the specification of TTML1.

[1] http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/






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