UDP file options

UDP file is of the form:

udp://<ip>:<port>[?<option>[&<option>]...]

Here is the list of supported options:

buffer_size=<size_in_bytes>:  UDP maximum receive buffer size in bytes. Note that although it can be set to any value, the actual value is capped by maximum allowed size defined by the underlying operating system. On linux, the maximum size allowed can be retrieved using sysctl net.core.rmem_max and configured using sysctl -w net.core.rmem_max=<size_in_bytes>. interface=<addr>:  Multicast group interface address. Only the packets sent to this address are received. Default to “0.0.0.0” if not specified. reuse=0|1:Allow or disallow reusing UDP sockets. source=<addr>:Multicast source ip address. Only the packets sent from this source address are received. Enables Source Specific Multicast (SSM) if set. timeout=<microseconds>:  UDP timeout in microseconds.

Example:

udp://224.1.2.30:88?interface=10.11.12.13&reuse=1

Note

UDP is by definition unreliable. There could be packets dropped.

UDP packets do not get lost magically. There are things you can do to minimize the packet loss. A common cause of packet loss is buffer overrun, either in send buffer or receive buffer.

On Linux, you can check UDP errors by monitoring the output from netstat -suna command.

If there is an increase in send buffer errors from the netstat output, then try increasing buffer_size in [FFmpeg](https://ffmpeg.org/ffmpeg-protocols.html#udp).

If there is an increase in receive buffer errors, then try increasing buffer_size in UDP options (See above) or increasing –io_cache_size. buffer_size in UDP options defines the UDP buffer size of the underlying system while io_cache_size defines the size of the internal circular buffer managed by Shaka Packager.