videomixer: GStreamer Good Plugins 1.0 Plugins Reference Manual

## videomixer videomixer |

## Properties

GstVideoMixer2Background | background | Read / Write

## Types and Values

struct | GstVideoMixer2
enum | GstVideoMixer2Background

## Object Hierarchy

        GObject
        ╰── GInitiallyUnowned
            ╰── GstObject
                ╰── GstElement
                    ╰── GstVideoMixer2

## Implemented Interfaces

GstVideoMixer2 implements GstChildProxy.

## Description

Videomixer can accept AYUV, ARGB and BGRA video streams. For each of the requested sink pads it will compare the incoming geometry and framerate to define the output parameters. Indeed output video frames will have the geometry of the biggest incoming video stream and the framerate of the fastest incoming one.

Videomixer will do colorspace conversion.

Individual parameters for each input stream can be configured on the GstVideoMixer2Pad.

### Sample pipelines

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    gst-launch-1.0 \
      videotestsrc pattern=1 ! \
      video/x-raw,format=AYUV,framerate=\(fraction\)10/1,width=100,height=100 ! \
      videobox border-alpha=0 top=-70 bottom=-70 right=-220 ! \
      videomixer name=mix sink_0::alpha=0.7 sink_1::alpha=0.5 ! \
      videoconvert ! xvimagesink \
      videotestsrc ! \
      video/x-raw,format=AYUV,framerate=\(fraction\)5/1,width=320,height=240 ! mix.

A pipeline to demonstrate videomixer used together with videobox. This should show a 320x240 pixels video test source with some transparency showing the background checker pattern. Another video test source with just the snow pattern of 100x100 pixels is overlaid on top of the first one on the left vertically centered with a small transparency showing the first video test source behind and the checker pattern under it. Note that the framerate of the output video is 10 frames per second.

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    gst-launch-1.0 videotestsrc pattern=1 ! \
      video/x-raw, framerate=\(fraction\)10/1, width=100, height=100 ! \
      videomixer name=mix ! videoconvert ! ximagesink \
      videotestsrc !  \
      video/x-raw, framerate=\(fraction\)5/1, width=320, height=240 ! mix.

A pipeline to demostrate bgra mixing. (This does not demonstrate alpha blending).

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    gst-launch-1.0 videotestsrc pattern=1 ! \
      video/x-raw,format =I420, framerate=\(fraction\)10/1, width=100, height=100 ! \
      videomixer name=mix ! videoconvert ! ximagesink \
      videotestsrc ! \
      video/x-raw,format=I420, framerate=\(fraction\)5/1, width=320, height=240 ! mix.

A pipeline to test I420

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    gst-launch-1.0 videomixer name=mixer sink_1::alpha=0.5 sink_1::xpos=50 sink_1::ypos=50 ! \
      videoconvert ! ximagesink \
      videotestsrc pattern=snow timestamp-offset=3000000000 ! \
      "video/x-raw,format=AYUV,width=640,height=480,framerate=(fraction)30/1" ! \
      timeoverlay ! queue2 ! mixer. \
      videotestsrc pattern=smpte ! \
      "video/x-raw,format=AYUV,width=800,height=600,framerate=(fraction)10/1" ! \
      timeoverlay ! queue2 ! mixer.

A pipeline to demonstrate synchronized mixing (the second stream starts after 3 seconds)

## Synopsis

### Element Information

plugin | videomixer
author | Wim Taymans <wim@fluendo.com>, Sebastian Dröge <sebastian.droege@collabora.co.uk>
class | Filter/Editor/Video/Compositor

### Element Pads

name | sink_%u
direction | sink
presence | request
details | video/x-raw, format=(string){ AYUV, BGRA, ARGB, RGBA, ABGR, Y444, Y42B, YUY2, UYVY, YVYU, I420, YV12, NV12, NV21, Y41B, RGB, BGR, xRGB, xBGR, RGBx, BGRx }, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]

name | src
direction | source
presence | always
details | video/x-raw, format=(string){ AYUV, BGRA, ARGB, RGBA, ABGR, Y444, Y42B, YUY2, UYVY, YVYU, I420, YV12, NV12, NV21, Y41B, RGB, BGR, xRGB, xBGR, RGBx, BGRx }, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]

## Functions

## Types and Values

### struct GstVideoMixer2

    struct GstVideoMixer2;

The opaque GstVideoMixer2 structure.

### enum GstVideoMixer2Background

The different backgrounds videomixer can blend over.

#### Members

VIDEO_MIXER2_BACKGROUND_CHECKER | checker pattern background |
VIDEO_MIXER2_BACKGROUND_BLACK | solid color black background |
VIDEO_MIXER2_BACKGROUND_WHITE | solid color white background |
VIDEO_MIXER2_BACKGROUND_TRANSPARENT | background is left transparent and layers are composited using "A OVER B" composition rules. This is only applicable to AYUV and ARGB (and variants) as it preserves the alpha channel and allows for further mixing. |

## Property Details

### The `“background”` property

      “background”               GstVideoMixer2Background

Background type.

Flags: Read / Write

Default value: Checker pattern