Support for TTML as source file text format

[teb]

Are there any plans on adding TTML based subtitles as allowed input format for DASH and HLS any time soon ? (DVB-TT, SMPTE-TT, EBU-TT, IMSC1 or raw TTML) ?

[Kongqun Yang]

TTML passthrough is supported for DASH. For TTML output in iso-bmff, please follow this issue: #87.

[teb]

TTML passthrough is supported for DASH. For TTML output in iso-bmff, please follow this issue: #87.

What about TTML in and WEBVTT out for HLS ? or alternatively TTML in and IMSC1 out for HLSv7+?

[Kongqun Yang]

What about TTML in and WEBVTT out for HLS ?

That is not supported right now.

or alternatively TTML in and IMSC1 out for HLSv7+?

HLS requires TTML / IMSC1 in iso-bmff, which can be addressed by #87.

[Wendong Li]

@kqyang

Regarding the TTML text input support:

HLS requires TTML / IMSC1 in iso-bmff, which can be addressed by #87.

It seems #87 has already been resolved. However the limitations on TTML text input support for HLS still seem to be in place.

shaka-packager/packager/packager.cc

Line 555 in 634af65

 "HLS does not support TTML in xml format."); 

shaka-packager/packager/packager.cc

Line 565 in 634af65

 "Converting TTML to other formats is not supported"); 

Could you please confirm if there is anything else left that blocks the removal of these limitations?