Revision as of 15:24, 21 March 2023

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VAR-SOM-MX93 Streaming Video

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.

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.

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)
app:  appsink: AppSink
autodetect:  autoaudiosink: Auto audio sink
autodetect:  autovideosink: Auto video sink
bluez:  a2dpsink: Bluetooth A2DP sink
bluez:  avdtpsink: Bluetooth AVDTP sink
coreelements:  fakesink: Fake Sink
coreelements:  fdsink: Filedescriptor Sink
coreelements:  filesink: File 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                  1.20.3
  License                  LGPL
  Source module            gst-plugins-bad
  Source release date      2022-06-15
  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)NV61, (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)NV61, (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:
  alpha               : Wayland surface alpha value, apply custom alpha value to wayland surface
                        flags: readable, writable
                        Float. Range:               0 -               1 Default:               0 
  async               : Go asynchronously to PAUSED
                        flags: readable, writable
                        Boolean. Default: true
  blocksize           : Size in bytes to pull per buffer (0 = default)
                        flags: readable, writable
                        Unsigned Integer. Range: 0 - 4294967295 Default: 4096 
  display             : Wayland display name to connect to, if not supplied via the GstContext
                        flags: readable, writable
                        String. Default: null
  enable-last-sample  : Enable the last-sample property
                        flags: readable, writable
                        Boolean. Default: true
  enable-tile         : When enabled, the sink propose VSI tile modifier to VPU
                        flags: readable, writable
                        Boolean. Default: false
  fullscreen          : Whether the surface should be made fullscreen 
                        flags: readable, writable
                        Boolean. Default: false
  last-sample         : The last sample received in the sink
                        flags: readable
                        Boxed pointer of type "GstSample"
  max-bitrate         : The maximum bits per second to render (0 = disabled)
                        flags: readable, writable
                        Unsigned Integer64. Range: 0 - 18446744073709551615 Default: 0 
  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: 5000000 
  name                : The name of the object
                        flags: readable, writable, 0x2000
                        String. Default: "waylandsink0"
  parent              : The parent of the object
                        flags: readable, writable, 0x2000
                        Object of type "GstObject"
  processing-deadline : Maximum processing time for a buffer in nanoseconds
                        flags: readable, writable
                        Unsigned Integer64. Range: 0 - 18446744073709551615 Default: 15000000 
  qos                 : Generate Quality-of-Service events upstream
                        flags: readable, writable
                        Boolean. Default: true
  render-delay        : Additional render delay of the sink in nanoseconds
                        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
  stats               : Sink Statistics
                        flags: readable
                        Boxed pointer of type "GstStructure"
                                                        average-rate: 0
                                                             dropped: 0
                                                            rendered: 0

  sync                : Sync on the clock
                        flags: readable, writable
                        Boolean. Default: true
  throttle-time       : The time to keep between rendered buffers (0 = disabled)
                        flags: readable, writable
                        Unsigned Integer64. Range: 0 - 18446744073709551615 Default: 0 
  ts-offset           : Timestamp offset in nanoseconds
                        flags: readable, writable
                        Integer64. Range: -9223372036854775808 - 9223372036854775807 Default: 0 
  window-height       : Wayland sink preferred window height in pixel
                        flags: readable, writable
                        Integer. Range: -1 - 2147483647 Default: -1 
  window-width        : Wayland sink preferred window width in pixel
                        flags: readable, writable
                        Integer. Range: -1 - 2147483647 Default: -1

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

Test pattern with specific parameters on the input element:

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

References

The GStreamer website
NXP BSP Linux Users Guide, Multimedia section download link

MX9 GSTREAMER: Difference between revisions