MediaStream

class MediaStream(**properties: Any)

Superclasses: Object

Subclasses: MediaFile

Implemented Interfaces: Paintable

GtkMediaStream is the integration point for media playback inside GTK.

GTK provides an implementation of the GtkMediaStream interface that is called MediaFile.

Apart from application-facing API for stream playback, GtkMediaStream has a number of APIs that are only useful for implementations and should not be used in applications: prepared, unprepared, update, ended, seek_success, seek_failed, gerror, error, error_valist.

Methods

class MediaStream

gerror(error: GError) → None

Sets self into an error state.

This will pause the stream (you can check for an error via get_error in your GtkMediaStream.pause() implementation), abort pending seeks and mark the stream as prepared.

if the stream is already in an error state, this call will be ignored and the existing error will be retained.

To unset an error, the stream must be reset via a call to unprepared.

Parameters:

error – the GError to set

get_duration() → int

Gets the duration of the stream.

If the duration is not known, 0 will be returned.

get_ended() → bool

Returns whether the streams playback is finished.

get_error() → GError | None

If the stream is in an error state, returns the GError explaining that state.

Any type of error can be reported here depending on the implementation of the media stream.

A media stream in an error cannot be operated on, calls like play or seek will not have any effect.

GtkMediaStream itself does not provide a way to unset an error, but implementations may provide options. For example, a MediaFile will unset errors when a new source is set, e.g. with set_file.

get_loop() → bool

Returns whether the stream is set to loop.

See set_loop for details.

get_muted() → bool

Returns whether the audio for the stream is muted.

See set_muted for details.

get_playing() → bool

Return whether the stream is currently playing.

get_timestamp() → int

Returns the current presentation timestamp in microseconds.

get_volume() → float

Returns the volume of the audio for the stream.

See set_volume for details.

has_audio() → bool

Returns whether the stream has audio.

has_video() → bool

Returns whether the stream has video.

is_prepared() → bool

Returns whether the stream has finished initializing.

At this point the existence of audio and video is known.

is_seekable() → bool

Checks if a stream may be seekable.

This is meant to be a hint. Streams may not allow seeking even if this function returns True. However, if this function returns False, streams are guaranteed to not be seekable and user interfaces may hide controls that allow seeking.

It is allowed to call seek on a non-seekable stream, though it will not do anything.

is_seeking() → bool

Checks if there is currently a seek operation going on.

pause() → None

Pauses playback of the stream.

If the stream is not playing, do nothing.

play() → None

Starts playing the stream.

If the stream is in error or already playing, do nothing.

realize(surface: Surface) → None

Called by users to attach the media stream to a GdkSurface they manage.

The stream can then access the resources of surface for its rendering purposes. In particular, media streams might want to create a GdkGLContext or sync to the GdkFrameClock.

Whoever calls this function is responsible for calling unrealize before either the stream or surface get destroyed.

Multiple calls to this function may happen from different users of the video, even with the same surface. Each of these calls must be followed by its own call to unrealize.

It is not required to call this function to make a media stream work.

Parameters:

surface – a GdkSurface

seek(timestamp: int) → None

Start a seek operation on self to timestamp.

If timestamp is out of range, it will be clamped.

Seek operations may not finish instantly. While a seek operation is in process, the seeking property will be set.

When calling seek() during an ongoing seek operation, the new seek will override any pending seek.

Parameters:

timestamp – timestamp to seek to.

seek_failed() → None

Ends a seek operation started via GtkMediaStream.seek() as a failure.

This will not cause an error on the stream and will assume that playback continues as if no seek had happened.

See seek_success for the other way of ending a seek.

seek_success() → None

Ends a seek operation started via GtkMediaStream.seek() successfully.

This function will unset the GtkMediaStream:ended property if it was set.

See seek_failed for the other way of ending a seek.

set_loop(loop: bool) → None

Sets whether the stream should loop.

In this case, it will attempt to restart playback from the beginning instead of stopping at the end.

Not all streams may support looping, in particular non-seekable streams. Those streams will ignore the loop setting and just end.

Parameters:

loop – True if the stream should loop

set_muted(muted: bool) → None

Sets whether the audio stream should be muted.

Muting a stream will cause no audio to be played, but it does not modify the volume. This means that muting and then unmuting the stream will restore the volume settings.

If the stream has no audio, calling this function will still work but it will not have an audible effect.

Parameters:

muted – True if the stream should be muted

set_playing(playing: bool) → None

Starts or pauses playback of the stream.

Parameters:

playing – whether to start or pause playback

set_volume(volume: float) → None

Sets the volume of the audio stream.

This function call will work even if the stream is muted.

The given volume should range from 0.0 for silence to 1.0 for as loud as possible. Values outside of this range will be clamped to the nearest value.

If the stream has no audio or is muted, calling this function will still work but it will not have an immediate audible effect. When the stream is unmuted, the new volume setting will take effect.

Parameters:

volume – New volume of the stream from 0.0 to 1.0

stream_ended() → None

Pauses the media stream and marks it as ended.

This is a hint only, calls to play may still happen.

The media stream must be prepared when this function is called.

Added in version 4.4.

stream_prepared(has_audio: bool, has_video: bool, seekable: bool, duration: int) → None

Called by GtkMediaStream implementations to advertise the stream being ready to play and providing details about the stream.

Note that the arguments are hints. If the stream implementation cannot determine the correct values, it is better to err on the side of caution and return True. User interfaces will use those values to determine what controls to show.

This function may not be called again until the stream has been reset via stream_unprepared.

Added in version 4.4.

Parameters:

• has_audio – True if the stream should advertise audio support

• has_video – True if the stream should advertise video support

• seekable – True if the stream should advertise seekability

• duration – The duration of the stream or 0 if unknown

stream_unprepared() → None

Resets a given media stream implementation.

stream_prepared can then be called again.

This function will also reset any error state the stream was in.

Added in version 4.4.

unrealize(surface: Surface) → None

Undoes a previous call to realize().

This causes the stream to release all resources it had allocated from surface.

Parameters:

surface – the GdkSurface the stream was realized with

update(timestamp: int) → None

Media stream implementations should regularly call this function to update the timestamp reported by the stream.

It is up to implementations to call this at the frequency they deem appropriate.

The media stream must be prepared when this function is called.

Parameters:

timestamp – the new timestamp

Properties

class MediaStream

props.duration: int

The stream’s duration in microseconds or 0 if unknown.

props.ended: bool

Set when playback has finished.

props.error: GError

None for a properly working stream or the GError that the stream is in.

props.has_audio: bool

Whether the stream contains audio.

props.has_video: bool

Whether the stream contains video.

props.loop: bool

Try to restart the media from the beginning once it ended.

props.muted: bool

Whether the audio stream should be muted.

props.playing: bool

Whether the stream is currently playing.

props.prepared: bool

Whether the stream has finished initializing and existence of audio and video is known.

props.seekable: bool

Set unless the stream is known to not support seeking.

props.seeking: bool

Set while a seek is in progress.

props.timestamp: int

The current presentation timestamp in microseconds.

props.volume: float

Volume of the audio stream.

Virtual Methods

class MediaStream

do_pause() → None

Pauses playback of the stream.

If the stream is not playing, do nothing.

do_play() → bool

do_realize(surface: Surface) → None

Called by users to attach the media stream to a GdkSurface they manage.

The stream can then access the resources of surface for its rendering purposes. In particular, media streams might want to create a GdkGLContext or sync to the GdkFrameClock.

Whoever calls this function is responsible for calling unrealize before either the stream or surface get destroyed.

Multiple calls to this function may happen from different users of the video, even with the same surface. Each of these calls must be followed by its own call to unrealize.

It is not required to call this function to make a media stream work.

Parameters:

surface – a GdkSurface

do_seek(timestamp: int) → None

Start a seek operation on self to timestamp.

If timestamp is out of range, it will be clamped.

Seek operations may not finish instantly. While a seek operation is in process, the seeking property will be set.

When calling seek() during an ongoing seek operation, the new seek will override any pending seek.

Parameters:

timestamp – timestamp to seek to.

do_unrealize(surface: Surface) → None

Undoes a previous call to realize().

This causes the stream to release all resources it had allocated from surface.

Parameters:

surface – the GdkSurface the stream was realized with

do_update_audio(muted: bool, volume: float) → None

Parameters:

• muted

• volume

Fields

class MediaStream

parent_instance