Source / Video processing

video.ffmpeg.testsrc

ffmpeg's test source video (useful for testing and debugging).

Type:

(?id : string) -> source('a)

Synchronization:

This source uses the FFmpeg input stream as synchronization source when self_sync=true and connected.

Arguments:

• id (of type string, which defaults to "video.testsrc")

Methods:

• buffered (of type () -> [string * float]): Length of buffered data.
• clock (of type clock): The source's clock
• duration (of type () -> float): Estimation of the duration of the current track.
• elapsed (of type () -> float): Elapsed time in the current track.
• fallible (of type bool): Indicate if a source may fail, i.e. may not be ready to stream.
• generate_frame (of type () -> unit): Generate a frame from the source without consuming it. This can be useful in advanced cases where generating a frame is required to trigger some side effect like calculating some metadata before making a decision. You should make sure that the source is available before calling this function and it should only be called inside synchronous streaming loop callback such as on_frame!
• id (of type () -> string): Identifier of the source.
• insert_metadata (of type (?new_track : bool, [string * string]) -> unit): Dynamically insert metadata in a stream. Inserts a new track with the given metadata if new_track is true.
• is_active (of type () -> bool): true if the source is active, i.e. it is continuously animated by its own clock whenever it is ready. Typically, true for outputs and sources such as input.http.
• is_ready (of type () -> bool): Indicate if a source is ready to stream. This does not mean that the source is currently streaming, just that its resources are all properly initialized.
• is_started (of type () -> bool): true if the output or source is started.
• is_up (of type () -> bool): Indicate that the source can be asked to produce some data at any time. This is true when the source is currently being used or if it could be used at any time, typically inside a switch or fallback.
• last_metadata (of type () -> [string * string]?): Return the last metadata from the source.
• log (of type {level : (() -> int).{set : (int) -> unit}}): Get or set the source's log level, from 1 to 5.
• register_command (of type (?usage : string?, description : string, string, ((string) -> string)) -> unit): Register a server command for this source. Command is registered under the source's id namespace when it gets up and de-registered when it gets down.
• remaining (of type () -> float): Estimation of remaining time in the current track.
• reset_last_metadata_on_track (of type (() -> bool).{set : (bool) -> unit}): If true, the source's last_metadata is reset on each new track. If a metadata is present along with the track mark, then it becomes the new last_metadata, otherwise, last_metadata becomes null`.
• seek (of type (float) -> float): Seek forward, in seconds (returns the amount of time effectively seeked).
• self_sync (of type () -> bool): Is the source currently controlling its own real-time loop.
• self_sync_description (of type () -> string): This source uses the FFmpeg input stream as synchronization source when self_sync=true and connected.
• set_url (of type ({string}) -> unit): Set the source's url.
• skip (of type () -> unit): Skip to the next track.
• start (of type () -> unit): Ask the source or output to start.
• status (of type () -> string): Return the current status of the source, either "stopped" (the source isn't trying to relay the HTTP stream), "starting" (polling task is about to begin) "polling" (attempting to connect to the HTTP stream), "connected " (connected to , buffering or playing back the stream) or "stopping" (source is stopping).
• stop (of type () -> unit): Ask the source or output to stop.
• time (of type () -> float): Get a source's time, based on its assigned clock.
• url (of type () -> string): Return the source's current url.

Callbacks:

• on_connect (of type (synchronous : bool, (() -> unit)) -> unit): Call a given handler Function to execute when a source is connected.
• on_disconnect (of type (synchronous : bool, (() -> unit)) -> unit): Call a given handler when a source is disconnected.
• on_error (of type (synchronous : bool, ((error) -> unit)) -> unit): Call a given handler when an error occurs.
• on_frame (of type (?before : bool, synchronous : bool, (() -> unit)) -> unit): Call a given handler on frame. When before is true, callback is executed before computing the frame and after otherwise
• on_frame_checksum (of type (?before : ((string?) -> unit)?, synchronous : bool, ((cache : string?, string) -> unit)) -> unit): Call a given handler Register callbacks to compute frame checksums for debugging purposes. This is useful to track frame content changes through the streaming pipeline. The before callback is called before computing the frame with the checksum of the cached frame (if any, null otherwise). The main callback is called after computing the frame with the checksum of the generated frame and the remaining cache (if any).
• on_metadata (of type (synchronous : bool, (([string * string]) -> unit)) -> unit): Call a given handler to execute on each metadata
• on_position (of type (position : {float}, ?remaining : bool, ?allow_partial : bool, synchronous : bool, ((float, [string * string]) -> unit)) -> unit): Call a given handler on track position. If remaining is false, callback is executed when position in track is more or equal to position. If remaining is true, callback is executed when remaining time in the current track is less or equal to position. Keep in mind that elapsed time is exact while remaining time is always estimated. Remaining time is usually more accurate for file-based sources. When allow_partial is true, if the current track ends before the offset position is reached, callback is still executed
• on_shutdown (of type (synchronous : bool, (() -> unit)) -> unit): Call a given handler to be called when source shuts down
• on_start (of type (synchronous : bool, (() -> unit)) -> unit): Call a given handler when source starts
• on_stop (of type (synchronous : bool, (() -> unit)) -> unit): Call a given handler when source stops
• on_track (of type (synchronous : bool, (([string * string]) -> unit)) -> unit): Call a given handler on track marks
• on_wake_up (of type (synchronous : bool, (() -> unit)) -> unit): Call a given handler to be called after the source is asked to get ready