diff options
| author | Jan Ekström <jan.ekstrom@24i.com> | 2022-07-22 13:57:54 +0300 |
|---|---|---|
| committer | Jan Ekström <jeebjp@gmail.com> | 2023-02-03 16:17:29 +0200 |
| commit | 9a820ec8b1e2323b70a1cebd204bf459bf7daa1a (patch) | |
| tree | d463a94f5b00866c8706ab67004ba45bd0cb7472 /doc | |
| parent | 746d27455b00f6baca2a1e4ab206cd40bf187598 (diff) | |
ffmpeg: add video heartbeat capability to fix_sub_duration
Splits the currently handled subtitle at random access point
packets that can be configured to follow a specific output stream.
Currently only subtitle streams which are directly mapped into the
same output in which the heartbeat stream resides are affected.
This way the subtitle - which is known to be shown at this time
can be split and passed to muxer before its full duration is
yet known. This is also a drawback, as this essentially outputs
multiple subtitles from a single input subtitle that continues
over multiple random access points. Thus this feature should not
be utilized in cases where subtitle output latency does not matter.
Co-authored-by: Andrzej Nadachowski <andrzej.nadachowski@24i.com>
Co-authored-by: Bernard Boulay <bernard.boulay@24i.com>
Signed-off-by: Jan Ekström <jan.ekstrom@24i.com>
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/ffmpeg.texi | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi index 81e04f6983..592c4b4393 100644 --- a/doc/ffmpeg.texi +++ b/doc/ffmpeg.texi @@ -1342,6 +1342,22 @@ List all hardware acceleration components enabled in this build of ffmpeg. Actual runtime availability depends on the hardware and its suitable driver being installed. +@item -fix_sub_duration_heartbeat[:@var{stream_specifier}] +Set a specific output video stream as the heartbeat stream according to which +to split and push through currently in-progress subtitle upon receipt of a +random access packet. + +This lowers the latency of subtitles for which the end packet or the following +subtitle has not yet been received. As a drawback, this will most likely lead +to duplication of subtitle events in order to cover the full duration, so +when dealing with use cases where latency of when the subtitle event is passed +on to output is not relevant this option should not be utilized. + +Requires @option{-fix_sub_duration} to be set for the relevant input subtitle +stream for this to have any effect, as well as for the input subtitle stream +having to be directly mapped to the same output in which the heartbeat stream +resides. + @end table @section Audio Options |