#10659: Converting to ass subtitles results in overlap. -------------------------------------+------------------------------------- Reporter: typological | Owner: (none) Type: defect | Status: new Priority: normal | Component: | undetermined Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by typological): I'm new to ffmpeg's codebase, I know the following patch is horrible, but it's a start. Problem seems to be the following: ASS uses only 10ms precision. AVPackets store start time and duration and not end time; in this case, the first packet had a duration of 4766ms which gets rounded to 4770ms when converting to the ASS timebase. The start time also gets rounded upwards and this adds a + 1 to the end time that would not have happened had the end time been rounded to 10ms itself. the patch makes ass subtitles a special case, and uses a rescale_ts function that rounds duration + start, then subtracts the start. not sure what are the possible issues that could appear from this change. -- Ticket URL: <https://trac.ffmpeg.org/ticket/10659#comment:1> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker