Incorrect written MP4 Sample Description Entry for DTS codec family

[rix]

Summary of the bug:
According to ETSI TS 102 114 Annex E, and ETSI TS 103 491 Annex B, DTS codec family should be signaled with specific Sample Description Entry boxes and DTSSpecificBox. FFmpeg currently does not produce files conforming to these specs, making these files unplayable on playback systems following the spec.

Please refer to ETSI TS 102 114 Table E-1 and ETSI TS 103 491 Table B-1 for the Sample Description Entry tag mapping for different DST codecs.

How to reproduce:

% ffmpeg -i https://fate-suite.ffmpeg.org/dts/dts.ts -c:a copy dts.mp4

Inspect the resulting MP4 shows the Sample Description Entry has mp4a tag instead of dtsc, and no {{ddts}} box.