Not strictly related to HEVC encoding but since you’re already touching Transcoder code anyway you should know that someone recently broke PGS/VOBSUB burn-in. It now falls back to software encoding (for HDR) and tries to inlineass instead of overlay which obviously doesn’t work. This means it’s currently not possible to watch media (which needs to be transcoded) with external image-based subtitles:
| SDR | HDR | |
|---|---|---|
| SRT (internal) | HW | HW |
| SRT (external) | HW | HW |
| VOBSUB (internal) | HW | SW |
| VOBSUB (external) | FAIL | FAIL |
| PGS (internal) | HW | SW |
| PGS (external) | FAIL | FAIL |
