DART-MX8M GSTREAMER

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VAR-SOM-MX8M-NANO Streaming Video

1 Introduction to GStreamer

GStreamer is a powerful pipeline-based multimedia framework.
It allows programmers to create a variety of media-handling components, including simple audio playback, audio and video playback, recording, streaming and editing.
This is not a GStreamer reference manual but an overview for using it on the Variscite i.MX8 products.
This release uses the gstreamer-imx set of GStreamer 1.0 plugins for NXP's i.MX platform, which make use of the i.MX multimedia capabilities.

1.1 Major GStreamer commands

There are two major commands:
gst-inspect - allows you to to get documentation on available elements and detailed information on a specific element.
gst-launch - allows you to create and execute GStreamer pipelines.

1.1.1 gst-inspect

Lists all available elements:

# gst-inspect-1.0

Lists all available sink elements:

# gst-inspect-1.0 | grep sink

For example:

# gst-inspect-1.0 | grep sink
alsa:  alsasink: Audio sink (ALSA)
waylandsink:  waylandsink: wayland video sink
shm:  shmsink: Shared Memory Sink
decklink:  decklinkaudiosink: Decklink Audio Sink
decklink:  decklinkvideosink: Decklink Video Sink
ximagesink:  ximagesink: Video sink
soup:  souphttpclientsink: HTTP client sink
autodetect:  autovideosink: Auto video sink
autodetect:  autoaudiosink: Auto audio sink
gdkpixbuf:  gdkpixbufsink: GdkPixbuf sink
playback:  playsink: Player Sink
video4linux2:  v4l2sink: Video (video4linux2) Sink
fbdevsink:  fbdevsink: fbdev video sink
tcp:  tcpclientsink: TCP client sink
tcp:  tcpserversink: TCP server sink
…

Detailed help information on a specific element:

# gst-inspect-1.0 <name of the element>

For example, the output for waylandsink:

# gst-inspect-1.0 waylandsink
Factory Details:
  Rank                     primary + 2 (258)
  Long-name                wayland video sink
  Klass                    Sink/Video
  Description              Output to wayland surface
  Author                   Sreerenj Balachandran <sreerenj.balachandran@intel.com>, George Kiagiadakis <george.kiagiadakis@collabora.com>

Plugin Details:
  Name                     waylandsink
  Description              Wayland Video Sink
  Filename                 /usr/lib/gstreamer-1.0/libgstwaylandsink.so
  Version                  1.14.0
  License                  LGPL
  Source module            gst-plugins-bad
  Source release date      2018-03-19
  Binary package           GStreamer Bad Plug-ins source release
  Origin URL               Unknown package origin

GObject
 +----GInitiallyUnowned
       +----GstObject
             +----GstElement
                   +----GstBaseSink
                         +----GstVideoSink
                               +----GstWaylandSink

Implemented Interfaces:
  GstVideoOverlay
  GstWaylandVideo

Pad Templates:
  SINK template: 'sink'
    Availability: Always
    Capabilities:
      video/x-raw
                 format: { (string)BGRx, (string)BGRA, (string)RGBx, (string)xBGR, (string)xRGB, (string)RGBA, (string)ABGR,
                           (string)ARGB, (string)RGB, (string)BGR, (string)RGB16, (string)BGR16, (string)YUY2, (string)YVYU,
                           (string)UYVY, (string)AYUV, (string)NV12, (string)NV21, (string)NV16, (string)YUV9, (string)YVU9,
                           (string)Y41B, (string)I420, (string)YV12, (string)Y42B, (string)v308 }
                  width: [ 1, 2147483647 ]
                 height: [ 1, 2147483647 ]
              framerate: [ 0/1, 2147483647/1 ]
      video/x-raw(memory:DMABuf)
                 format: { (string)BGRx, (string)BGRA, (string)RGBx, (string)xBGR, (string)xRGB, (string)RGBA, (string)ABGR,
                           (string)ARGB, (string)RGB, (string)BGR, (string)RGB16, (string)BGR16, (string)YUY2, (string)YVYU,
                           (string)UYVY, (string)AYUV, (string)NV12, (string)NV21, (string)NV16, (string)YUV9, (string)YVU9,
                           (string)Y41B, (string)I420, (string)YV12, (string)Y42B, (string)v308 }
                  width: [ 1, 2147483647 ]
                 height: [ 1, 2147483647 ]
              framerate: [ 0/1, 2147483647/1 ]

Element has no clocking capabilities.
Element has no URI handling capabilities.

Pads:
  SINK: 'sink'
    Pad Template: 'sink'

Element Properties:
  name                : The name of the object
                        flags: readable, writable
                        String. Default: "waylandsink0"
  parent              : The parent of the object
                        flags: readable, writable
                        Object of type "GstObject"
  sync                : Sync on the clock
                        flags: readable, writable
                        Boolean. Default: true
  max-lateness        : Maximum number of nanoseconds that a buffer can be late before it is dropped (-1 unlimited)
                        flags: readable, writable
                        Integer64. Range: -1 - 9223372036854775807 Default: 20000000 
  qos                 : Generate Quality-of-Service events upstream
                        flags: readable, writable
                        Boolean. Default: true
  async               : Go asynchronously to PAUSED
                        flags: readable, writable
                        Boolean. Default: true
  ts-offset           : Timestamp offset in nanoseconds
                        flags: readable, writable
                        Integer64. Range: -9223372036854775808 - 9223372036854775807 Default: 0 
  enable-last-sample  : Enable the last-sample property
                        flags: readable, writable
                        Boolean. Default: true
  last-sample         : The last sample received in the sink
                        flags: readable
                        Boxed pointer of type "GstSample"
  blocksize           : Size in bytes to pull per buffer (0 = default)
                        flags: readable, writable
                        Unsigned Integer. Range: 0 - 4294967295 Default: 4096 
  render-delay        : Additional render delay of the sink in nanoseconds
                        flags: readable, writable
                        Unsigned Integer64. Range: 0 - 18446744073709551615 Default: 0 
  throttle-time       : The time to keep between rendered buffers (0 = disabled)
                        flags: readable, writable
                        Unsigned Integer64. Range: 0 - 18446744073709551615 Default: 0 
  max-bitrate         : The maximum bits per second to render (0 = disabled)
                        flags: readable, writable
                        Unsigned Integer64. Range: 0 - 18446744073709551615 Default: 0 
  show-preroll-frame  : Whether to render video frames during preroll
                        flags: readable, writable
                        Boolean. Default: true
  window-width        : Wayland sink preferred window width in pixel
                        flags: readable, writable
                        Integer. Range: -1 - 2147483647 Default: -1 
  window-height       : Wayland sink preferred window height in pixel
                        flags: readable, writable
                        Integer. Range: -1 - 2147483647 Default: -1 
  display             : Wayland display name to connect to, if not supplied via the GstContext
                        flags: readable, writable
                        String. Default: null
  alpha               : Wayland surface alpha value, apply custom alpha value to wayland surface
                        flags: readable, writable
                        Float. Range:               0 -               1 Default:               0 
  enable-tile         : When enabled, the sink propose VSI tile modifier to VPU
                        flags: readable, writable
                        Boolean. Default: false



2 Test Pattern Stream

Test pattern allows you to display pre-built image/video patterns on the display. It is very useful when you don't have a camera but still want to test GStreamer.
Default test pattern:

# gst-launch-1.0 videotestsrc ! autovideosink

Gst1.jpg

Test pattern with specific parameters on the input element:

# gst-launch-1.0 videotestsrc pattern=circular ! autovideosink

Gst2.jpg

3 Camera Loopback

Stream video from a camera to a display:

# gst-launch-1.0 v4l2src device=/dev/video0 ! autovideosink

4 Video Recording

Example of encoding and saving a short video stream from a camera to an MJPEG-encoded AVI file:

# gst-launch-1.0 v4l2src device=/dev/video0 num-buffers=100 ! video/x-raw,width=1920,height=1080 ! jpegenc ! avimux ! filesink location=./test_jpeg.avi



5 RTP Video streaming

Encode video stream from camera using a software based JPEG encoder and stream it over RTP:

# gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw,width=1280,height=720 ! jpegenc ! rtpjpegpay ! udpsink host=192.168.20.60 port=1223

6 References