View Source HLS.Packager (HTTP Live Streaming (HLS) library v2.0.0)
The HLS.Packager module is responsible for managing and generating media and master playlists
for HTTP Live Streaming (HLS). It handles various tasks such as loading and saving playlists,
inserting new streams, uploading segments and maintaining synchronization points for different streams.
Summary
Functions
Adds a new track to the packager. Tracks can only be added as long as the master playlist has not been written yet.
Allows to append something to an URIs path.
Returns a specification to start this module under a supervisor.
Will force that the next added segment has an EXT-X-DISCONTINUITY tag.
Writes down the remaining segments and marks all playlists as finished (EXT-X-ENDLIST). Deletes pending playlists.
Checks if the given track already exists in the packager.
Returns the maximum track duration.
Returns the next synchronization point which
can then be passed to the sync/2 function.
The put_init_section/3 function adds or updates the initialization section (such as an MPEG-4 ‘init’ section)
for the given track. This section will be used for all upcoming segments and is essential for media formats like fragmented
MP4 where an initial header is required before media segments can be played.
Adds a new segment asynchronously to the given track.
Generates a relative segment uri for the given playlist and segment index.
Initializes a new packager with a storage and its root manifest uri.
By default, the packager will raise an exception when trying to resume a
finished track. This behaviour can be controlled with the resume_finished_tracks option.
Synchronizes all media playlists and writes down the master playlist as soon as needed.
Returns the duration of the given track.
Returns a relative variant uri for a given track id.
Returns the tracks managed by the packager.
Types
@type add_track_opt() :: {:stream, HLS.VariantStream.t() | HLS.AlternativeRendition.t()} | {:segment_extension, String.t()} | {:target_segment_duration, float()} | {:codecs, [String.t()]}
@type track_id() :: String.t()
Functions
@spec add_track(GenServer.server(), track_id(), [add_track_opt()]) :: :ok
Adds a new track to the packager. Tracks can only be added as long as the master playlist has not been written yet.
Examples
Packager.add_track(
packager,
"416x234",
stream: %HLS.VariantStream{
uri: URI.new!("stream_416x234.m3u8"),
bandwidth: 341_276,
resolution: {416, 234},
codecs: ["avc1.64000c", "mp4a.40.2"]
},
segment_extension: ".m4s",
target_segment_duration: 7
)Allows to append something to an URIs path.
Examples
iex> HLS.Packager.append_to_path(URI.new!("file://a.m3u8"), "_480p")
URI.new!("file://a_480p.m3u8")
iex> HLS.Packager.append_to_path(URI.new!("file://a/b.m3u8"), "_480p")
URI.new!("file://a/b_480p.m3u8")Returns a specification to start this module under a supervisor.
See Supervisor.
@spec discontinue_track(GenServer.server(), track_id()) :: :ok
Will force that the next added segment has an EXT-X-DISCONTINUITY tag.
@spec flush(GenServer.server()) :: :ok
Writes down the remaining segments and marks all playlists as finished (EXT-X-ENDLIST). Deletes pending playlists.
@spec has_track?(GenServer.server(), track_id()) :: boolean()
Checks if the given track already exists in the packager.
@spec max_track_duration(GenServer.server()) :: non_neg_integer()
Returns the maximum track duration.
@spec next_sync_point(GenServer.server(), pos_integer()) :: pos_integer()
Returns the next synchronization point which
can then be passed to the sync/2 function.
@spec put_init_section(GenServer.server(), track_id(), binary() | nil) :: :ok
The put_init_section/3 function adds or updates the initialization section (such as an MPEG-4 ‘init’ section)
for the given track. This section will be used for all upcoming segments and is essential for media formats like fragmented
MP4 where an initial header is required before media segments can be played.
If the init section has changed, it is uploaded and associated with future segments. If no payload is provided, the init section is removed.
@spec put_segment(GenServer.server(), track_id(), binary(), float()) :: :ok
Adds a new segment asynchronously to the given track.
Generates a relative segment uri for the given playlist and segment index.
Examples
iex> HLS.Packager.relative_segment_uri(
...> URI.new!("file://x/stream_video_480p.m3u8"),
...> ".aac",
...> 48
...> )
URI.new!("stream_video_480p/00000/stream_video_480p_00048.aac")Initializes a new packager with a storage and its root manifest uri.
By default, the packager will raise an exception when trying to resume a
finished track. This behaviour can be controlled with the resume_finished_tracks option.
Examples
HLS.Packager.start_link(
storage: HLS.Storage.File.new(),
manifest_uri: URI.new!("file://stream.m3u8"),
resume_finished_tracks: false,
restore_pending_segments: true,
master_written_callback: nil
)@spec sync(GenServer.server(), pos_integer()) :: :ok
Synchronizes all media playlists and writes down the master playlist as soon as needed.
@spec track_duration(GenServer.server(), track_id()) :: {:ok, non_neg_integer()} | {:error, :not_found}
Returns the duration of the given track.
@spec track_variant_uri(GenServer.server(), track_id()) :: URI.t()
Returns a relative variant uri for a given track id.
@spec tracks(GenServer.server()) :: %{required(track_id()) => HLS.Packager.Track.t()}
Returns the tracks managed by the packager.