[FFmpeg-devel] [PATCH]lavf/mxfdec: Export EIA608 Closed Captions by default

Marton Balint cus at passwd.hu
Sun Feb 17 02:40:50 EET 2019

On Sat, 16 Feb 2019, Carl Eugen Hoyos wrote:

> Hi!
> I am not sure why there is an option to disable Closed Captions export,
> but disabling the export by default seems like a bad idea to me.

SMPTE 436M can be any kind of ancillary data, not only closed captions. 
That is why the default behaviour (pass all the data to userspace so a 
userspace app can parse it properly) makes sense. Some applications might 
depend on this.

The eia608_extract option is a hack which effectively replaces the generic 
ancillary data stream with the parsed subtitle stream. The reason for the 
hack is that libavcodec has no API for such a parser or filter which reads 
a data stream and generates one (ore more) subtitle streams...


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