ttp:contentProfiles missing from IMSC1.1 Text Profile output option

[jbaden]

Hello,

The TTCONV documentation references IMSC1.1 Text Profile as one of the three supported output formats (the others being SRT and WebVTT).

However, when using --otype: TTML there is no declaration written into the <tt> element to signal the appropriate, corresponding profile. Can ttp:contentProfiles="http://www.w3.org/ns/ttml/profile/imsc1.1/text be added to the <tt> element when --otype: TTML is specified?

This is causing some processing issues since we are reliant upon the presence of this attribute/value.

Thanks!
-Justin

[palemieux]

There are several distinct issues:

• the presence of ttp:contentProfiles would make the document incompatible with EBU-TT-D, which is perhaps undesirable for some applications. This can be addressed by putting the signaling behind a config parameter
• the TTML writer does not currently guarantee that the resulting document is an IMSC 1.1 document, although it is when using an SCC or EBU STL input. It is a larger undertaking to ensure that the output is always IMSC 1.1.

[jbaden]

Thank you, @palemieux. Understood regarding the points above.

Having the ability to specify the profile using a config parameter would be great!

[cconcolato]

Maybe the TTML writer could emit a warning or even fail if IMSC1.1 is requested but not possible?

[palemieux]

Yes, in IMSC 1.1 mode, the TTML writer should both convert to IMSC 1.1 when possible, e.g. when c units are used, and fail when that conversion is not possible.