Thursday, October 27, 2016

Cost effective video source for development


We all know that Raspberry Pi is very powerful Single board Linux computer that is not much bigger than credit card and can be used to learn programming, develop products quickly. It is also capable of many of the things that the desktop PC does like spreadsheets, word processing and playing high definition video and games. It also has Bluetooth Low Energy and WiFi connectivity on board.
Raspberry Pi can also be used as a video player/source and can provide output video resolutions till 1080p with different display timings. By default it will output at 1080p60. It has a default application 'omxplayer' to decode audio/video bitstreams from most of the container formats like MP4, MKV, AVI etc., Raspberry Pi foundation provides Linux based Raspbian OS distribution which can be installed on SD card and can be used to boot the Raspberry Pi hardware.
To get different output display timing we just need to modify the /boot/config.txt file after booting the Raspberry Pi with Raspbian OS and reboot the board, Add the below lines in the /boot/config.txt file to get 1080p24
    hdmi_group=1 hdmi_mode=32
To get 1080p30 set
    hdmi_group=34
For more information on other supported display timing refer the following links
https://www.raspberrypi.org/documentation/configuration/config-txt.md https://www.raspberrypi.org/forums/viewtopic.php?t=5851 To change the output display timing without reboot use the following commands. You may not be able to see the command console after issuing the below commands and hence it is advised to SSH to the board and issue the commands.
  • tvservice -e "CEA 16"         --------> to set 1080p60
  • tvservice -e "CEA 31"         --------> to set 1080p50
  • tvservice -e "CEA 34"         --------> to set 1080p30
  • tvservice -e "CEA 33"         --------> to set 1080p25
Play the video again using the 'omxplayer' application and now your display device connected to the Raspberry Pi will start displaying the video
Example: omxplayer /opt/vc/src/hello_pi/hello_video/test.h264