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:
Lists all available sink elements:
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:
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 <[email protected]>, George Kiagiadakis <[email protected]>
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:
Test pattern with specific parameters on the input element:
References¶
- The GStreamer website
- NXP BSP Linux Users Guide, Multimedia section download link