DART-MX8M GSTREAMER

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Streaming Video

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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 Video Playback

The i.MX8M can decode and playback HEVC(H.265), VP9, etc. encoded videos with HDR at resolutions of up to 4Kp60 UHD (3840×2160p @ 60fps) using its internal hardware Video Processing Unit (VPU).
See the sink pad capabilities in the vpudec element details for the complete list of codecs supported by the i.MX8M VPU decoder.


Example of a video file playback using the playbin element (making use of the VPU decoder):

# gst-launch-1.0 playbin uri=file:/run/media/sda1/big_buck_bunny.mp4 

Example of a video file playback while explicitly specifying a pipeline (making use of the VPU decoder):

# gst-launch-1.0 filesrc location=/run/media/sda1/big_buck_bunny.mp4 typefind=true ! video/quicktime ! aiurdemux ! queue max-size-time=0 ! vpudec ! autovideosink

6 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

7 References