adds an optional `--hls_start_time_offset` parameter, that, when
used, adds `EXT-X-START` tags to the HLS media playlists.
The EXT-X-START tag allows to specify the location where the player
starts playing, either from start (positive value) or from end (negative
value).
This is especially useful in case of livestreams where this tag can be
used to set the target latency of the playback.
Reference: https://datatracker.ietf.org/doc/html/rfc8216#section-4.3.5.2
The RFC says, that the `EXT-X-START` tag could also be added to the
master playlist, but my tests have shown that most players only respect
it when it's in the media playlists.
Fixes#970
---------
Co-authored-by: Joey Parrish <joeyparrish@google.com>
This work was done over ~80 individual commits in the `cmake` branch,
which are now being merged back into `main`. As a roll-up commit, it is
too big to be reviewable, but each change was reviewed individually in
context of the `cmake` branch. After this, the `cmake` branch will be
renamed `cmake-porting-history` and preserved.
---------
Co-authored-by: Geoff Jukes <geoffjukes@users.noreply.github.com>
Co-authored-by: Bartek Zdanowski <bartek.zdanowski@gmail.com>
Co-authored-by: Carlos Bentzen <cadubentzen@gmail.com>
Co-authored-by: Dennis E. Mungai <2356871+Brainiarc7@users.noreply.github.com>
Co-authored-by: Cosmin Stejerean <cstejerean@gmail.com>
Co-authored-by: Carlos Bentzen <carlos.bentzen@bitmovin.com>
Co-authored-by: Cosmin Stejerean <cstejerean@meta.com>
Co-authored-by: Cosmin Stejerean <cosmin@offbytwo.com>
HLS uses the EXT-X-MEDIA-SEQUENCE tag at the start of a live playlist in
order to specify the first segment sequence number. This is because any
live playlist have a limited number of segments, and they also keep
updating with new segments while removing old ones. When a player refreshes
the playlist, this information is important for keeping track of segments
positions.
When the packager starts, it naturally starts this count from zero. However,
there are many situations where the packager may be restarted, without this
meaning starting this value from zero (but continuing a previous sequence).
The most common situations are problems in the encoder feeding the packager.
With those cases in mind, this parameter allows to set the initial
EXT-X-MEDIA-SEQUENCE value. This way, it's possible to continue the sequence
number from previous packager run.
Closes#691.
- Add flags and stream descriptor fields for HLS.
- Remove fields from MuxerOptions. Instead pass them directly to
HlsNotifyMuxerListener.
- Rebase segment names to the master playlist's path where it makes
sense.
Change-Id: If4f54bc56ff46dc6140859a79ed66f7b99112ed7
Marcus Wichelmann
Joey Parrish
Daniel Cantarín
KongQun Yang
Rintaro Kuroiwa