Skip to content

Adjust frag_duration setting in stream #59135

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
allenporter merged 1 commit into from
Nov 6, 2021
Merged

Adjust frag_duration setting in stream #59135

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
18 changes: 9 additions & 9 deletions homeassistant/components/stream/worker.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -102,18 +102,18 @@ def make_new_av(
# The LL-HLS spec allows for a fragment's duration to be within the range [0.85x,1.0x]
# of the part target duration. We use the frag_duration option to tell ffmpeg to try to
# cut the fragments when they reach frag_duration. However, the resulting fragments can
# have variability in their durations and can end up being too short or too long. If
# there are two tracks, as in the case of a video feed with audio, the fragment cut seems
# to be done on the first track that crosses the desired threshold, and cutting on the
# audio track may result in a shorter video fragment than desired. Conversely, with a
# have variability in their durations and can end up being too short or too long. With a
# video track with no audio, the discrete nature of frames means that the frame at the
# end of a fragment will sometimes extend slightly beyond the desired frag_duration.
# Given this, our approach is to use a frag_duration near the upper end of the range for
# outputs with audio using a frag_duration at the lower end of the range for outputs with
# only video.
# If there are two tracks, as in the case of a video feed with audio, there is an added
# wrinkle as the fragment cut seems to be done on the first track that crosses the desired
# threshold, and cutting on the audio track may also result in a shorter video fragment
# than desired.
# Given this, our approach is to give ffmpeg a frag_duration somewhere in the middle
# of the range, hoping that the parts stay pretty well bounded, and we adjust the part
# durations a bit in the hls metadata so that everything "looks" ok.
"frag_duration": str(
self._stream_settings.part_target_duration
* (98e4 if add_audio else 9e5)
self._stream_settings.part_target_duration * 9e5
),
}
if self._stream_settings.ll_hls
Expand Down