[FFmpeg-user] Copying ARIB captions does not work

[Moritz Barsnick]

On Mon, May 13, 2019 at 13:00:20 +0200, Jakub Vojáček wrote:
> The captions are recognized on the input but no longer recognized on the
> output. Should that be supported? We have been doing the same thing with
> dvb_subtitles and it worked as expected but doesn't work with arib.
[...]
> Input #0, mpegts, from 'test_copy.ts':
>   Duration: 00:05:00.70, start: 1.400000, bitrate: 16128 kb/s
>   Program 1
>     Metadata:
>       service_name    : Service01
>       service_provider: FFmpeg
>     Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B),
> yuv420p(tv, bt709, top first), 1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps,
> 29.97 tbr, 90k tbn, 59.94 tbc
>     Stream #0:1[0x101](por): Audio: aac_latm (HE-AAC) ([17][0][0][0] /
> 0x0011), 48000 Hz, stereo, fltp
>     Stream #0:2[0x102](eng): Audio: aac_latm (HE-AAC) ([17][0][0][0] /
> 0x0011), 48000 Hz, 5.1, fltp
>     Stream #0:3[0x103]: Data: bin_data ([6][0][0][0] / 0x0006)
> [@1557745032]: Unsupported codec with id 100359 for input stream 3

If I see ffmpeg's code correctly, ffmpeg has the capability to demux
(and decode, using libaribb24) ARIB captions, but it does not have the
capability to mux them correctly. Therefore your "copy codec" remuxing
loses the properties in the resulting MPEG-TS.

I may be wrong, this is my interpretation of how ARIB works and what's
happening.

Regards,
Moritz