Testing a Video Stream

This article describes how to set up a Streaming for Video connection between two computers, start a multicast with an encoded transport stream, test that the receiving computer is receiving packets, and play the streamed media content.

The following instructions requires two computers installed with Streaming for Video:
  • computer A: Linux computer with the built-in sender license.
  • computer B: Linux computer with a receiver license.

The following steps must be performed on computer A:

  1. Start ascp4 to transport streams when an input is available.
    The following example assumes you have SSH key access to computer B from computer A.
    # ascp4 --mode=send --user=computerB_user -i ~/.ssh/id_rsa --host=computerB  --compression=none --read-threads=1 --write-threads=1 udp://233.3.3.3:3000?loopback=1&ttl=2 udp://233.4.4.4:4000?loopback=1&ttl=2
    Note: For more information about the command syntax for starting a FASPStream, see Streaming for Video Command Syntax.
  2. Download a test file to stream.
    In your browser, download the ed24p_00.zip test file from the www.w6rz.net website (a community transport stream testing website):

    http://www.w6rz.net/ed24p_00.zip

    Extract the contents into an easily accessible folder. You may provide your own media file, but the examples in this documentation assume that you are using the ed24p_00.zip transport stream file located at /temp/ed24p_00.ts.

  3. Provide a multicast stream of a test file to ascp4.
    Run the ffmpeg command with the location of the media file and set the URI of the resulting stream:
    # ffmpeg -re  -i /temp/ed24p_00.ts -vcodec copy -acodec copy -f mpegts  "udp://233.3.3.3:3000?ttl=2&pkt_size=1316"
  4. Check to see the output of ascp4 to make sure the Rate of transfer is going up to the expected speed.

Now that your stream is running and ascp4 shows that it is transporting the stream, check the receiver is receiving the media file. The following steps must be performed on computer B:

  1. Run the tcpdump command to check streams are coming.

    The port number corresponds to port configured in the destination multicast URI. In the example below, the destination port was configured as 4000.

    # sudo tcpdump upd and port 4000
  2. Play the media file over the stream.
    The following example uses the third-party, open-source vlc command. If you do not have vlc on your computer, run the following command:
    # sudo apt-get install vlc-nox

    Using VLC, play the media from the stream.

    1. Open VLC.
    2. Click Open media. In the resulting dialog, go to the Network tab and click Open RTP/UDP Stream.
    3. Configure the settings according to your multicast URI.
      Option Value
      Protocol UDP
      Mode Multicast
      IP Address 233.4.4.4
      Port (for the IP Address) 4000


Your media file should now be playing in the VLC media player.