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VAR-SOM-MX6 GSTREAM FSLC

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VAR-SOM-MX6 - 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.MX6 products.
This release uses the gstreamer-imx set of GStreamer 1.0 plugins for Freescale'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 i.MX6 specific elements:

$ gst-inspect-1.0 | grep imx

For example:

root@var-som-mx6:~# gst-inspect-1.0 | grep imx
imxipu:  imxipuvideotransform: Freescale IPU video transform
imxipu:  imxipuvideosink: Freescale IPU video sink
imxipu:  imxipucompositor: Freescale IPU video compositor
imxg2d:  imxg2dvideosink: Freescale G2D video sink
imxg2d:  imxg2dvideotransform: Freescale G2D video transform
imxg2d:  imxg2dcompositor: Freescale G2D video compositor
imxpxp:  imxpxpvideosink: Freescale PxP video sink
imxpxp:  imxpxpvideotransform: Freescale PxP video transform
imxaudio:  imxuniaudiodec: Freescale i.MX uniaudio decoder
imxaudio:  imxmp3audioenc: Freescale i.MX MP3 encoder
imxeglvivsink:  imxeglvivsink: Freescale EGL video sink
imxvpu:  imxvpudec: Freescale VPU video decoder
imxvpu:  imxvpuenc_h263: Freescale VPU h.263 video encoder
imxvpu:  imxvpuenc_h264: Freescale VPU h.264 video encoder
imxvpu:  imxvpuenc_mpeg4: Freescale VPU MPEG-4 video encoder
imxvpu:  imxvpuenc_mjpeg: Freescale VPU motion JPEG video encoder
imxv4l2videosrc:  imxv4l2videosrc: V4L2 CSI Video Source

Detailed help information on a specific element:

$ gst-inspect-1.0 imxeglvivsink

For example:

root@var-som-mx6:~# gst-inspect-1.0 imxeglvivsink
====== IMXV4L2SINK: 4.0.9 build on Aug  8 2016 12:47:08. ======
Factory Details:
  Rank                     primary + 1 (257)
  Long-name                Freescale EGL video sink
  Klass                    Sink/Video
  Description              Video output using the i.MX6 Vivante GPU
  Author                   Carlos Rafael Giani <dv@pseudoterminal.org>

Plugin Details:
  Name                     imxeglvivsink
  Description              EGL/GLES sink using Vivante direct textures
  Filename                 /usr/lib/gstreamer-1.0/libgstimxeglvivsink.so
  Version                  0.12.2
  License                  LGPL
  Source module            gstreamer-imx
  Binary package           Unknown package release
  Origin URL               Unknown package origin

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

Implemented Interfaces:
  GstNavigation
  GstVideoOverlay

Pad Templates:
  SINK template: 'sink'
    Availability: Always
    Capabilities:
      video/x-raw
                 format: { I420, YV12, YV21, NV12, NV21, UYVY, RGB16, RGBA, BGRA, RGBx, BGRx, BGR, ARGB, ABGR, xRGB, xBGR }
                  width: [ 1, 2147483647 ]
                 height: [ 1, 2147483647 ]
              framerate: [ 0/1, 2147483647/1 ]


Element Flags:
  no flags set

Element Implementation:
  Has change_state() function: gst_imx_egl_viv_sink_change_state

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: "imxeglvivsink0"
  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
  fullscreen          : Whether or not to set the created window to fullscreen mode (ignored if application provides a window handle)
                        flags: readable, writable
                        Boolean. Default: false
  force-aspect-ratio  : When enabled, scaling will respect original aspect ratio
                        flags: readable, writable
                        Boolean. Default: true
  native-display      : String identifying the display to use (default value uses the default display)
                        flags: readable, writable
                        String. Default: null
  window-x-coord      : X coordinate of the window's top left corner, in pixels
                        flags: readable, writable
                        Integer. Range: -2147483648 - 2147483647 Default: 0
  window-y-coord      : Y coordinate of the window's top left corner, in pixels
                        flags: readable, writable
                        Integer. Range: -2147483648 - 2147483647 Default: 0
  window-width        : Window width, in pixels (0 = automatically set to the video input width)
                        flags: readable, writable
                        Unsigned Integer. Range: 0 - 2147483647 Default: 0
  window-height       : Window height, in pixels (0 = automatically set to the video input height)
                        flags: readable, writable
                        Unsigned Integer. Range: 0 - 2147483647 Default: 0
  borderless-window   : Disable window borders, bypassing any window manager
                        flags: readable, writable
                        Boolean. Default: false
                   

1.1.2 gst-launch

For Example, display a test pattern on the monitor:

$ export DISPLAY=:0
$ gst-launch-1.0 -v videotestsrc ! imxeglvivsink

1.1.3 i.MX6 major elements

Prefix
Element Name
description
imxaudio imxmp3audioenc imx mp3 audio encoder
imxg2d imxg2dvideosink IMX G2D video sink (blitter-based, zerocopy)
imxipu imxipuvideosink IMX IPU video sink (blitter-based, zerocopy)
imxpxp imxpxpvideosink IMX PxP video sink (blitter-based, zerocopy)
imxeglvivsink imxeglvivsink IMX EGL video sink (zerocopy)
imxv4l2videosrc imxv4l2videosrc IMX V4L2 CSI Video Source (zerocopy)
imxvpu imxvpudec IMX VPU video decoder (zerocopy)
imxvpu imxvpuenc_h263 VPU-based h.263 video encoder (zerocopy)
imxvpu imxvpuenc_h264 VPU-based H264 video encoder (zerocopy)
imxvpu imxvpuenc_h264 VPU-based MPEG video encoder (zerocopy)
imxvpu imxvpuenc_jpeg VPU-based JPEG video encoder (zerocopy)
imxipu imxipuvideotransform IMX IPU video transform
imxpxp imxpxpvideotransform IMX PXP video transform
imxg2d imxg2dvideotransform IMX G2D video transform
imxipu imxipucompositor IMX IPU video compositor
imxg2d imxg2dcompositor IMX G2D video compositor
Only imxeglvivsink will work with X11 or Wayland. More optimized blitter-base PXP, IPU and G2D sinks will work with fslc_framebuffer only
See more detailed description here

2 Test Pattern Stream

Test pattern allows you to display pre build 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:

$ export DISPLAY=:0
$ gst-launch-1.0 videotestsrc ! imxeglvivsink borderless-window="true" force-aspect-ratio="false"

Gst1.jpg

Test pattern with specific paramters on the input element

$ gst-launch-1.0 videotestsrc pattern=circular ! imxeglvivsink borderless-window="true" force-aspect-ratio="false"

Gst2.jpg

Test pattern with specific paramters on the output element

$ gst-launch-1.0 videotestsrc ! imxeglvivsink window-width="1280" window-height="720" borderless-window="true" force-aspect-ratio="false"

Gst4.jpg

Test pattern with specific paramters on the input and output elements

$ gst-launch-1.0 videotestsrc pattern=circular ! imxeglvivsink window-width="1280" window-height="720" borderless-window="true" force-aspect-ratio="false"

Gst3.jpg

3 Camera Loopback

  • Stream video from a camera to a display:
$ export DISPLAY=:0
$ gst-launch-1.0 imxv4l2videosrc device=/dev/video0 imx-capture-mode=5 fps-n=30 ! imxeglvivsink  window-width="1920" window-height="1080" borderless-window="true" force-aspect-ratio="false"
Only imxeglvivsink will work with X11 or Wayland with some rendering artifacts.
More optimized blitter-base imxg2dvideosink and imxipuvideosink sinks will properly work with fslc_framebuffer DISTRO only

Get the camera support format and resolution using gst-inspect-1.0 imxv4l2videosrc.
imx-capture-mode for ov5640 example resolutions:

ov5640_mode_VGA_640_480 = 0,
ov5640_mode_QVGA_320_240 = 1,
ov5640_mode_NTSC_720_480 = 2,
ov5640_mode_PAL_720_576 = 3,
ov5640_mode_720P_1280_720 = 4,
ov5640_mode_1080P_1920_1080 = 5 
  • And another pipeline example, the same as above, only with camera continuous auto focus enabled:
$ gst-launch-1.0 imxv4l2videosrc device=/dev/video0 imx-capture-mode=5 fps-n=30 focus-mode=6 ! imxeglvivsink  window-width="1920" window-height="1080" borderless-window="true" force-aspect-ratio="false"

4 Video Record

command:
gst-launch-1.0 imxv4l2videosrc device=$DEVICE num-buffers=300 imx-capture-mode=$MODE ! queue ! imxvpuenc_XXX ! $MUXER ! filesink location=output.$EXTENSION

Parameter comments:

• $DEVICE could be set to /dev/video, /dev/video0 or according to the system video input device.
• num-buffers - Number of buffers to output before sending EOS. deafult =-1 (unlimited)
• $MODE should be set according to camera format and resolution
• imxvpuenc_XXX can be imxvpuenc_mpeg4,imxvpuenc_h263, imxvpuenc_h264, and imxvpuenc_jpeg
• MUXER can be set as to qtmux, matroskamux, mp4mux, avimux, or flvmux
• EXTENSION is filename extension according to the muxer type.


Record video from a camera into a file. Encode it to h264 at a bitrate of 10mbit/s (CBR)
720p:

$ gst-launch-1.0 imxv4l2videosrc device=/dev/video0 imx-capture-mode=4 fps-n=30 num-buffers=300 ! queue ! imxvpuenc_h264 bittrate=10000 ! avimux ! filesink location=test.avi

1080p:

$ gst-launch-1.0 imxv4l2videosrc device=/dev/video0 imx-capture-mode=5 fps-n=30 num-buffers=300 ! queue ! imxvpuenc_h264 bitrate=10000 ! avimux ! filesink location=test.avi

To use ov5640 continuous auto focus while recording video to a file append focus-mode=6 to imxv4l2videosrc
For example

720p:

$ gst-launch-1.0 imxv4l2videosrc device=/dev/video0 imx-capture-mode=4 fps-n=30 num-buffers=300 focus-mode=6 ! queue ! imxvpuenc_h264 bittrate=10000 ! avimux ! filesink location=test.avi

1080p:

$ gst-launch-1.0 imxv4l2videosrc device=/dev/video0 imx-capture-mode=5 fps-n=30 num-buffers=300 focus-mode=6 ! queue ! imxvpuenc_h264 bitrate=10000 ! avimux ! filesink location=test.avi

5 Simple Movie Play

$ export DISPLAY=:0
$ gst-launch-1.0 playbin uri=file:/run/media/sda1/big_buck_bunny.mp4 

6 Compositing

The compositor is a new feature in gstreamer-imx 0.11.0. Just like with the compositor from gst-plugins-base 1.5.1 and newer, compositor elements support an arbitrary number of request sink pads, and one srcpad.

$ gst-launch-1.0   \
  imxg2dcompositor name=c background-color=0x223344 \
      sink_0::xpos=0 sink_0::ypos=90 sink_0::width=160 sink_0::height=110 sink_0::zorder=55 sink_0::fill_color=0xff00ff00 sink_0::alpha=0.39 sink_0::rotation=0 \
      sink_1::xpos=0 sink_1::ypos=20 sink_1::width=620 sink_1::height=380 sink_1::fill_color=0x44441133 ! \
    queue2 ! "video/x-raw, width=800, height=600" ! imxg2dvideosink \
  videotestsrc pattern=0 ! "video/x-raw, framerate=30/1" ! c.sink_0 \
  videotestsrc pattern=18 ! "video/x-raw, framerate=30/1" ! c.sink_1


See detailed description here

7 References

  • The GStreamer website
  • The gstreamer-imx README
  • The gstreamer-imx FAQ
  • A Deep Dive into Image Processing for i.MX 6 Application Processors presentation