Customizing Android & Yocto Splash Screens

lcd_gateworks_logo

Customizing Android & Yocto Splash Screens

Have you ever wanted to replace that ugly default logo or animation that is shown when your system boots up? Now you can with custom splash screens!

What is a Splash Screen?

  • The logo or image displayed on screen during the boot process of an embedded system

3 Splash Screens can be Customized:

  • Bootloader
  • Linux Kernel
  • Operating System

Why are Splash Screens Important?

  • Splash screen are displayed immediately conveying proper operation and responsiveness to the user
  • Replacing the splash screen logo with a company logo will effectively brand a product for customer deployment

Readmore on the Gateworks Software Wiki:
Customizing the Splash Screen

Adaptive Bitrate Streaming using GStreamer

Gateworks’ SBCs are widely used for streaming audio and video over the network via Ethernet, 802.11 WiFi, or 4G LTE Cellular.Networks are dynamic, whether from network load, RF interference or signal strength thus throughput will vary requiring intelligent and flexible applications to adjust as necessary.

Adaptive Bitrate Streaming is the concept of adjusting the quality of video and/or audio depending on the quality of the network connection or server load. This type of technology is widely implemented throughout technology today, evident in streaming services like Netflix and YouTube.

Gateworks created an example GStreamer application named gst-variable-rtsp-server. This application includes a mechanism for auto-adjusting the encoding bitrate depending on the number of clients connected to the server.

gst-variable-rtsp-server can change either the quant-param or the bitrate parameters of the imxvpuenc_h264 encoder. The quant-param will only be used if the pipeline is set to Variable Bitrate mode (VBR). This can be accomplished by passing in the -b 0 flag to the program. Otherwise, gst-variable-rtsp-server will change the bitrate of the stream.

The algorithm used to change both bitrate and quant-param are based on the --steps input (defaulted to 5). For example, if using the default steps value of 5, if the min bitrate was 500 and max bitrate was 2000, it would take 5 clients to adjustfrom the highest to the lowest quality.

In the below example, the rtsp server was configured to degrade from 10mbps to 400kbps bitrate within 5 steps. Please see below for our results.

gst-variable-rtsp-server --steps=5 --max-bitrate=10000 --min-bitrate=400 --src-element=imxv4l2videosrc --video-in=/dev/video0

quality_changes

For higher resolution images of the above, please view here (10Mbps), here (2.8Mbps), and here (400Kbps).

For more information and sample GStreamer pipelines, please visit our Software Wiki Pages:

GStreamer Compositing for Streaming H.264 Video

Gateworks recently featured a blog in which 8 video cameras were connected to a Gateworks Ventana SBC and then displayed on a HDMI monitor. This is useful for localized applications. For remote applications there is another solution.

Remote applications require streaming the multiple video streams over the network (Ethernet or WiFi). For bandwidth efficiency, all camera inputs can be joined together into a single frame and then transmitted across the network.

streamingdiagram3

To join all the streams into a single frame, a software element of GStreamercalled a compositor is used. Older versions of the compositor relied on the CPU and caused choppy video. Gateworks recently started using gstreamer-imx which contains a hardware accelerated compositor which is far superior. With this compositor, each stream can be positioned on the frame and then linked to a RTSP stream in the H.264 format.

An example is shown with two Gateworks Ventana SBCs that are on the same network.

Start the following pipeline on the SBC with the cameras connected:

gst-variable-rtsp-server -u \ "imxv4l2videosrc device=/dev/video2 queue-size=55 ! queue2 ! c.sink_0 \ imxv4l2videosrc device=/dev/video3 queue-size=55 ! queue2 ! c.sink_1 \ imxv4l2videosrc device=/dev/video4 queue-size=55 ! queue2 ! c.sink_2 \ imxv4l2videosrc device=/dev/video5 queue-size=55 ! queue2 ! c.sink_3 \ imxv4l2videosrc device=/dev/video6 queue-size=55 ! queue2 ! c.sink_4 \ imxv4l2videosrc device=/dev/video7 queue-size=55 ! queue2 ! c.sink_5 \ imxv4l2videosrc device=/dev/video8 queue-size=55 ! queue2 ! c.sink_6 \ imxv4l2videosrc device=/dev/video9 queue-size=55 ! queue2 ! c.sink_7 \ imxg2dcompositor name=c background-color=0xffffff \ sink_0::xpos=0 sink_0::ypos=0 sink_0::width=320 sink_0::height=360 sink_0::fill_color=0x00000000 \ sink_1::xpos=320 sink_1::ypos=0 sink_1::width=320 sink_1::height=360 sink_1::fill_color=0x00000000 \ sink_2::xpos=640 sink_2::ypos=0 sink_2::width=320 sink_2::height=360 sink_2::fill_color=0x00000000 \ sink_3::xpos=960 sink_3::ypos=0 sink_3::width=320 sink_3::height=360 sink_3::fill_color=0x00000000 \ sink_4::xpos=0 sink_4::ypos=360 sink_4::width=320 sink_4::height=360 sink_4::fill_color=0x00000000 \ sink_5::xpos=320 sink_5::ypos=360 sink_5::width=320 sink_5::height=360 sink_5::fill_color=0x00000000 \ sink_6::xpos=640 sink_6::ypos=360 sink_6::width=320 sink_6::height=360 sink_6::fill_color=0x00000000 \ sink_7::xpos=960 sink_7::ypos=360 sink_7::width=320 sink_7::height=360 sink_7::fill_color=0x00000000 \ ! queue2 ! video/x-raw, width=1280, height=720 ! imxipuvideotransform \ ! imxvpuenc_h264 bitrate=20000 ! rtph264pay name=pay0 pt=96"

Then, on the receiving board that is connected to an HDMI display, start the following pipeline with the actual IP address (example IP below) of the board with the cameras:

gst-launch-1.0 rtspsrc location=rtsp://172.24.10.210:9099/stream latency=100 ! \queue2 ! decodebin ! autovideosink

For more information andcode examples, please visit the related Gateworks Software Wiki links below:

 

Capturing 8 Video Inputs on Gateworks Ventana SBCs

Gateworks would like to introduce software support for the AVC8000nano Mini-PCIe card on the Ventana Single Board Computers.

final_screen_camerasFigure 1: Screen capture of 8 analog cameras displayed on a monitor using the Gateworks Ventana SBC

Many applications, such as surveillance, require multipleanalog video inputs from cameras for monitoring. These cameras can then be displayed on an HDMI monitor or streamed over the network.

final_camerasonboardFigure 2: Eightanalog video cameras mounted in a circular fashion for a panoramic capture

Gateworks has added driver support for the AVC8000nano in it’s Yocto Linux board support package. This driver support will reveal 8 video interfaces in Linux, such as /dev/video0, /dev/video1, etc. These video interfaces can then be accessed using GStreamer.

final_pictureofcardFigure 3: The AVC8000nano installed on a Gateworks Ventana SBC with 8 analog cameras connected

The OpenCV software library could be used to stitch the different inputs together to create a seamless panorama.

For more information and example GStreamer pipelines on how to use this card, please visit our Software Wiki Page:

AVC8000nano Software Wiki Page

Future blog posts will cover streaming multiple camera inputs as well as adaptive bitrate streaming! Please subscribe to the Gateworks blog to the right!

 

 

i.MX6 GStreamer-imx Plugins – Tutorial & Example Pipelines

Gateworks would like to announce the support of the GStreamer-imx plugins starting with Yocto 1.8on the Ventana family of Single Board Computers.

gstreamerpipeline

Gateworks, the leading supplier of Powerful ARM based Single Board Computer solutions using the Freescale i.MX6, has invested countless engineering hours researching and mastering GStreamer for the i.MX series of processors. Gateworks would like to share this GStreamer research with the rest of the i.MX community of developers!

There are two main versions of GStreamer used on the i.MX6 processor:0.10 and 1.0. Version 1.0 is now the latest standard.

The i.MX6 processor has hardware blocks such as the IPU (image processing unit), VPU (video processing unit), and GPU (graphical processing unit). The main advantage of using these hardware blocks is that there is no CPU cost for decoding/encoding a stream because another hardware block in the i.MX6 takes care of it. This leavestheCPU free to deal with other programs etc.

The GStreamer app works with ‘plugins’. A plugin comprises of elements that can do work on a media stream. For example, the imxvpudec is a VPU based decoder plugin.

This post is specifically about the plugins. There are different versions and sets of plugins available.

Gateworks has chosen to use the GStreamer-imx plugins for the following reasons:

  • Open Source Development model: The project is on github and is very active
  • The main developer has been a GStreamer contributer for some time now and is very active in the GStreamer community
  • The source is very well documented and easy to follow
  • Things are done in a very standard GStreamer way

Plugin List

For a thorough description of each plugin, why and how to use it, please visit the Gateworks Software Wiki GStreamer Page

The following is a list of plugins provided by the latest version of gstreamer-imx (0.11.0)

Type Plugin(s) Element(s) Comments
Audio Decoder imxaudio imxuniaudiodec Uses i.MX uniaudio codecs for decoding
Audio Encoder imxaudio imxmp3audioenc Uses i.MX for MP3 audio encoding
Device Sources imxv4l2video imxv4l2videosrc Get camera source via v4l2
Video Decoder imxvpu imxvpudec VPU Based decoder
Video Encoder imxvpu imxvpuenc_mjpeg; imxvpuenc_mpeg4; imxvpuenc_h264; imxvpuenc_h263 VPU Based encoders
Video Render (sink) imxg2d; imxpxp; imxeglvivsink; imxipu imxg2dvideosink; imxpxpvideosink; imxeglvivsink; imxipuvideosink g2d1, ipu1, pxp2, and egl (overlay) video sinks
Video Converter imxg2d; imxpxp; imxipu imxg2dvideotransform; imxpxpvideotransform; imxipuvideotransform g2d, pxp, egl and ipu video filter/converter/scalars3
Video Compositing imxg2d; imxipu imxg2dcompositor, imxipucompositor gpu/ipu accelerated compositing

1. The g2d sink is very flexible in the types of input video it can take, but doesn’t have the ability to convert to as many formats as the IPU can. On the other hand, the IPU is very picky with it’s input (e.g. requiring a 1px offset) and the kernel driver is very undocumented, but as stated before, it can convert between many colorspace formats.
2. Note that the PXP sinks are only applicable to the i.mx6solo and i.mx6dl processors.
3. Please see note 1 above.

Plugin Example Pipeline

For example, to encode a video from a camera on /dev/video2 into h.264 and save it to a file:

#Take camera input /dev/video2, encode it to h264 at a bitrate of 10mbit/s (CBR) and save to a file.
gst-launch-1.0 imxv4l2videosrc device=/dev/video2 ! imxvpuenc_h264 bitrate=10000 ! filesink location=/tmp/file.mp4

Many more pipeline examples are described and listed on the Gateworks Software Wiki GStreamer Pipelines page

Summary

Using GStreamer 1.0 with the GStreamer-imx plugins is a powerful way to access and apply the multimedia capabilities of the Freescale i.MX6 processors on the Gateworks SBCs.

For more information, visit theGateworks Software Wiki GStreamer Pipelines page

If there are other examples you would like to see, please add to the discussion!

Yocto 1.8 Linux BSP – Gateworks i.MX6 SBCs

yoctoproject_logo_cmyk

Gateworks would like to announcethe release & support of Yocto 1.8 on the Ventana Family of Single Board Computers that feature the Freescale i.MX6 processor. Yocto 1.8 is under the code name Fido. Yocto is a Linux operating system that Gateworks uses for video input and output, networking, GUI, IoT and more. Gateworks recommends all customers and engineers update from Yocto 1.7 to Yocto 1.8.

Yocto 1.8 Updates and Highlights:

  • Updated Linux Kernel. The kernel has been updated to the Gateworks downstream 3.14 vendor kernel.
  • Updated the gstreamer video framework to gstreamer-imx and gstreamer-1.0
    • Updated to the gstreamer-imx community based plugins for utilizing i.MX6 hardwareacceleration to provide increased flexibility over what is provided fromFreescale in gst-fsl-plugins
    • Included RTSP server application, gst-variable-rtsp-server
    • More gstreamer-imx information is available here
  • AVC8000nano Video Capture Mini-PCIe card for up to 8x D1 inputs
    • The driver is now loaded by default in Yocto 1.8 and tested with gstreamer-imx
    • This is very useful for surveillance and compositing many video sources into one screen
    • Find more information here
  • Updated uboot-envtools
  • Updated gsc-update tool
  • Support for the GW16113 IO Expansion module via the gwsoc software tool. More information available here.

To get started, Gateworks has posted Pre-Built images on the Yocto Wiki page. This includes tarballs and ubis for multimedia and gui images. The wiki page also documents building Yocto 1.8 from source.

Yocto Software Wiki Page

Please update to Yocto 1.8 and contact Gateworks with any questions. Their support team is happy and available to work with you!

Video & Audio On Gateworks Ventana Single Board Computers with Linux GStreamer

The Ventana Family of Single Board Computers from Gateworks offers a multitude of video and audio interfaces to meet the demands of new multimedia embedded systems. The primary method of accessing these interfaces is through software by the name of GStreamer. GStreamer is an open-source library that makes the handling of multimedia data more simple usingpipelines of elements that operate on multimedia data buffers. GStreamer can be used directly on the command line of a Ventana Single Board computer for quick prototyping and development with the gst-launch test application. For example, to play a video file stored on a USB flash drive connected to a Gateworks single board computer, the following GStreamer command would be used:

gst-launch filesrc location=/media/sda1/big_buck_bunny_720p_surround.avi ! decodebin2 ! mfw_v4lsink device=/dev/video16

Using GStreamer, an application can benefit from a large library of OpenSource elements that use well known algorithms to operate on multimedia data, including the elements provided by the fsl-gstreamer package that take advantage of the i.MX6 hardware acceleration. Customers can create custom applications that utilize GStreamer (above and beyond what gst-launch can provide) through the Gateworks SDK. GStreamer is a very powerful tool with thousands of options and plugins. Gateworks has created a wiki page that provides some simple examples to make getting started quickly easier on the Ventana Single Board Computers. Follow this link to the wiki for more examples and tutorials!

Gateworks GStreamer Software Wiki Page