videorate

This element takes an incoming stream of timestamped video frames. It will produce a perfect stream that matches the source pad's framerate.

The correction is performed by dropping and duplicating frames, no fancy algorithm is used to interpolate frames (yet).

By default the element will simply negotiate the same framerate on its source and sink pad.

This operation is useful to link to elements that require a perfect stream. Typical examples are formats that do not store timestamps for video frames, but only store a framerate, like Ogg and AVI.

A conversion to a specific framerate can be forced by using filtered caps on the source pad.

The properties in, out, duplicate and drop can be read to obtain information about number of input frames, output frames, dropped frames (i.e. the number of unused input frames) and duplicated frames (i.e. the number of times an input frame was duplicated, beside being used normally).

An input stream that needs no adjustments will thus never have dropped or duplicated frames.

When the silent property is set to FALSE, a GObject property notification will be emitted whenever one of the duplicate or drop values changes. This can potentially cause performance degradation. Note that property notification will happen from the streaming thread, so applications should be prepared for this.

The property rate allows the modification of video speed by a certain factor. It must not be confused with framerate. Think of rate as speed and framerate as flow.

Example pipelines

 gst-launch-1.0 -v uridecodebin uri=file:///path/to/video.ogg ! videoconvert ! videoscale ! videorate ! video/x-raw,framerate=15/1 ! autovideosink

Decode a video file and adjust the framerate to 15 fps before playing. To create a test Ogg/Theora file refer to the documentation of theoraenc.

 gst-launch-1.0 -v v4l2src ! videorate ! video/x-raw,framerate=25/2 ! theoraenc ! oggmux ! filesink location=recording.ogg

Capture video from a V4L device, and adjust the stream to 12.5 fps before encoding to Ogg/Theora.

 gst-launch-1.0 -v uridecodebin uri=file:///path/to/video.ogg ! videoconvert ! videoscale ! videorate ! video/x-raw,framerate=1/5 ! jpegenc ! multifilesink location=snapshot-%05d.jpg

Decode a video file and save a snapshot every 5 seconds as consecutively numbered jpeg file.

Hierarchy

GObject
    ╰──GInitiallyUnowned
        ╰──GstObject
            ╰──GstElement
                ╰──GstBaseTransform
                    ╰──videorate

Factory details

Authors: – Wim Taymans

Classification:Filter/Effect/Video

Rank – none

Plugin – gstvideorate

Package – GStreamer Base Plug-ins git

Pad Templates

sink

video/x-raw(ANY):

video/x-bayer(ANY):

image/jpeg(ANY):

image/png(ANY):

Presencealways

Directionsink


src

video/x-raw(ANY):

video/x-bayer(ANY):

image/jpeg(ANY):

image/png(ANY):

Presencealways

Directionsrc


Properties

average-period

“average-period” guint64

Arrange for maximum framerate by dropping frames beyond a certain framerate, where the framerate is calculated using a moving average over the configured.

Flags : Read / Write

Default value : 0


drop

“drop” guint64

Number of dropped frames

Flags : Read

Default value : 0


drop-only

“drop-only” gboolean

Only drop frames, no duplicates are produced.

Flags : Read / Write

Default value : false


duplicate

“duplicate” guint64

Number of duplicated frames

Flags : Read

Default value : 0


in

“in” guint64

Number of input frames

Flags : Read

Default value : 0


max-duplication-time

“max-duplication-time” guint64

Duplicate frames only if the gap between two consecutive frames does not exceed this duration.

Flags : Read / Write

Default value : 0


max-rate

“max-rate” gint

maximum framerate to pass through

Flags : Read / Write / Construct

Default value : 2147483647


name

“name” gchararray

The name of the object

Flags : Read / Write / Construct

Default value : NULL


new-pref

“new-pref” gdouble

Value indicating how much to prefer new frames (unused)

Flags : Read / Write

Default value : 1


out

“out” guint64

Number of output frames

Flags : Read

Default value : 0


parent

“parent” GstObject *

The parent of the object

Flags : Read / Write


qos

“qos” gboolean

Handle Quality-of-Service events

Flags : Read / Write

Default value : false


rate

“rate” gdouble

Factor of speed for frame displaying

Flags : Read / Write

Default value : 1


silent

“silent” gboolean

Don't emit notify for dropped and duplicated frames

Flags : Read / Write

Default value : true


skip-to-first

“skip-to-first” gboolean

Don't produce buffers before the first one we receive.

Flags : Read / Write

Default value : false


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