General Command Line Usage

FASPStream is used to transport MPEG transport streams (TS) over long distances. On the source host, the UDP provider captures packets delivered to a local multicast or unicast UDP port. The stream is transported reliably and in order to the remote host, where it is delivered to the desired local multicast or unicast UDP port.

General Command Line Usage

# /opt/aspera/bin/ascp4 -m minimum_rate -l target_rate --mode=mode --host=destination_hostname --compression=none --user=username --read-threads=1 --write-threads=1 input_multicast_uri output_multicast_uri

FASPStream uses the ascp4 command. For general command line usage of ascp4, see the ascp4 man page:

# man ascp4

FASPStream supports two modes: send and recv.
The ascp4 command defaults to multiple threads, but for reliable and in-order transport of streams you must use only one read and write thread.

Recommended Rate Settings for Media Streams

ascp4 Option	Description	Recommendation
-m	Minimum rate	Take the encoding rate of the transport stream and add 1 Mbps.
-l	Target rate	Take the minimum rate and add 10% of the minimum rate.

For example, if the encoding rate is 10 Mbps, use the following settings:

# /opt/aspera/bin/ascp4 -m 11M -l 13M ...

Multicast URI Syntax

The input multicast URI and the output multicast URI uses the same syntax.

multicast_protocol_scheme://stream_ip_address:port?option=value&option=value...

The multicast protocol scheme can be either udp or mcast. If the IP address of your stream is a multicast address, FASPStream uses multicast regardless of the protocol scheme (in other words, both udp and mcast use multicast). In order to use unicast addresses, you must use the udp scheme.

You can configure properties of the stream by adding options to the URI after the question mark (?), each separated by an ampersand (&). For supported options see the table below.

Option	Description	Default
pktsize=`packet_size`	Multicast packet size	1316
maxsize=`maximum_size`	Maximum stream length	No default
maxtime=`maximum_time`	Maximum stream duration, in seconds	No default
maxidle=`maximum_time`	Maximum idle duration, in seconds	No default
rcvbufsz=`buffer_size`	Receive buffer size	10MB
sndbufsz=`buffer_size`	Send buffer size	10MB
ifaddr=`ip_address`	Multicast interface IP address	0.0.0.0
ttl=`hops`	Multicast time-to-live	1
loopback=`boolean`	Multicast loopback	1

FASPStream Usage Examples

Sending Multicast Stream from Local Host to Remote Host

ascp4 --mode=send --host=desthost --compression=none --read-threads=1 --write-threads=1 udp://233.3.3.3:3000?loopback=1&ttl=2 udp://233.4.4.4:3000?loopback=1&ttl=2

Capture Local Multicast, Send to Remote Host, and Deliver as UDP Unicast

ascp4 --mode=send --host=desthost --compression=none --read-threads=1 --write-threads=1 udp://233.3.3.3:3000?loopback=1&ttl=2 udp://localhost:3000/