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)
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:
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 1.14.0
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
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:
Camera Loopback¶
Stream video from a camera to a display:
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
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
References¶
- The GStreamer website
- NXP BSP Linux Users Guide, Multimedia section download link