videorate: GStreamer Base Plugins 1.0 Plugins Reference Manual

## videorate videorate |

## Properties

guint64 | average-period | Read / Write
guint64 | drop | Read
gboolean | drop-only | Read / Write
guint64 | duplicate | Read
guint64 | in | Read
gint | max-rate | Read / Write / Construct
gdouble | new-pref | Read / Write
guint64 | out | Read
gboolean | silent | Read / Write
gboolean | skip-to-first | Read / Write
gdouble | rate | Read / Write
guint64 | max-duplication-time | Read / Write

## Types and Values

struct | GstVideoRate

## Object Hierarchy

        GObject
        ╰── GInitiallyUnowned
            ╰── GstObject
                ╰── GstElement
                    ╰── GstBaseTransform
                        ╰── GstVideoRate

## Description

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

    1
    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.

    1
    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.

    1
    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.

## Synopsis

### Element Information

plugin | videorate
author | Wim Taymans <wim@fluendo.com>
class | Filter/Effect/Video

### Element Pads

name | sink
direction | sink
presence | always
details | video/x-raw(ANY)
| video/x-bayer(ANY)
| image/jpeg(ANY)
| image/png(ANY)

name | src
direction | source
presence | always
details | video/x-raw(ANY)
| video/x-bayer(ANY)
| image/jpeg(ANY)
| image/png(ANY)

## Functions

## Types and Values

### struct GstVideoRate

    struct GstVideoRate;

Opaque data structure.

## Property Details

### The `“average-period”` property

      “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.

Owner: GstVideoRate

Flags: Read / Write

Allowed values: <= G_MAXLONG

Default value: 0

### The `“drop”` property

      “drop”                     guint64

Number of dropped frames.

Owner: GstVideoRate

Flags: Read

Default value: 0

### The `“drop-only”` property

      “drop-only”                gboolean

Only drop frames, no duplicates are produced.

Owner: GstVideoRate

Flags: Read / Write

Default value: FALSE

### The `“duplicate”` property

      “duplicate”                guint64

Number of duplicated frames.

Owner: GstVideoRate

Flags: Read

Default value: 0

### The `“in”` property

      “in”                       guint64

Number of input frames.

Owner: GstVideoRate

Flags: Read

Default value: 0

### The `“max-rate”` property

      “max-rate”                 gint

maximum framerate to pass through

Owner: GstVideoRate

Flags: Read / Write / Construct

Allowed values: >= 1

Default value: 2147483647

### The `“new-pref”` property

      “new-pref”                 gdouble

Value indicating how much to prefer new frames (unused).

Owner: GstVideoRate

Flags: Read / Write

Allowed values: [0,1]

Default value: 1

### The `“out”` property

      “out”                      guint64

Number of output frames.

Owner: GstVideoRate

Flags: Read

Default value: 0

### The `“silent”` property

      “silent”                   gboolean

Don't emit notify for dropped and duplicated frames.

Owner: GstVideoRate

Flags: Read / Write

Default value: TRUE

### The `“skip-to-first”` property

      “skip-to-first”            gboolean

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

Owner: GstVideoRate

Flags: Read / Write

Default value: FALSE

### The `“rate”` property

      “rate”                     gdouble

Factor of speed for frame displaying

Owner: GstVideoRate

Flags: Read / Write

Allowed values: >= 0

Default value: 1

Since: 1.12

### The `“max-duplication-time”` property

      “max-duplication-time”     guint64

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

Owner: GstVideoRate

Flags: Read / Write

Default value: 0

Since: 1.16