path: root/doc/protocols.texi

@chapter Protocols
@c man begin PROTOCOLS

Protocols are configured elements in FFmpeg which allow to access
resources which require the use of a particular protocol.

When you configure your FFmpeg build, all the supported protocols
are enabled by default. You can list them using the configure option
"--list-protocols".

You can disable all the protocols using the configure option
"--disable-protocols", and selectively enable a protocol using the
option "--enable-protocol=@var{PROTOCOL}", or you can disable a
particular protocol using the option
"--disable-protocol=@var{PROTOCOL}".

The option "-protocols" of the ff* tools will display the list of
the supported protocols.

A description of the currently available protocols follows.

@section concat

Physical concatenation protocol.

Allow to read and seek from many resource in sequence as they were an
unique resource.

An url accepted by this protocol has the syntax:
@example
concat:@var{URL1}|@var{URL2}|...|@var{URLN}
@end example

where @var{URL1}, @var{URL2}, ..., @var{URLN} are the urls of the
resource to be concatenated, each one possibly specifying a distinct
protocol.

For example to read a sequence of files @file{split1.mpeg},
@file{split2.mpeg}, @file{split3.mpeg} with @file{ffplay} use the
command:
@example
ffplay concat:split1.mpeg\|split2.mpeg\|split3.mpeg
@end example

Note that you may need to escape the character "|" which is special for
many shells.

@section file

File access protocol.

Allow to read from or read to a file.

For example to read from a file @file{input.mpeg} with @file{ffmpeg}
use the command:
@example
ffmpeg -i file:input.mpeg output.mpeg
@end example

Note that if not specified otherwise, the ff* tools will use the file
protocol by default, that is a resource specified with the name
"FILE.mpeg" is interpreted as it were the url "file:FILE.mpeg".

@section gopher

Gopher protocol.

@section http

HTTP (Hyper Text Trasfer Protocol).

@section mmst

MMS (Microsoft Media Server) protocol over TCP.

@section md5

MD5 output protocol.

Computes the MD5 hash of data written, and on close writes this to the
designated output or stdout if none is specified. It can be used to
test muxers without writing an actual file.

Some examples follow.
@example
# write the MD5 hash of the encoded AVI file in the file output.avi.md5
ffmpeg -i input.flv -f avi -y md5:output.avi.md5

# write the MD5 hash of the encoded AVI file to stdout
ffmpeg -i input.flv -f avi -y md5:
@end example

Note that some formats (typically mov) require the output protocol to
be seekable, so they will fail with the MD5 output protocol.

@section pipe

UNIX pipe access protocol.

Allow to read and write from UNIX pipes.

The accepted syntax is:
@example
pipe:[@var{number}]
@end example

@var{number} is the number corresponding to the file descriptor of the
pipe (e.g. 0 for stdin, 1 for stdout, 2 for stderr).
If @var{number} is not specified will use by default stdout if the
protocol is used for writing, stdin if the protocol is used for
reading.

For example to read from stdin with @file{ffmpeg}:
@example
cat test.wav | ffmpeg -i pipe:0
# this is the same as
cat test.wav | ffmpeg -i pipe:
@end example

For writing to stdout with @file{ffmpeg}:
@example
ffmpeg -i test.wav -f avi pipe:1 | cat > test.avi
# this is the same as
ffmpeg -i test.wav -f avi pipe: | cat > test.avi
@end example

Note that some formats (typically mov), require the output protocol to
be seekable, so they will fail with the pipe output protocol.

@section rtmp

Real-Time Messaging Protocol.

The Real-Time Messaging Protocol (RTMP) is used for streaming multime‐
dia content across a TCP/IP network.

The required syntax is:
@example
rtmp://@var{server}[:@var{port}][/@var{app}][/@var{playpath}]
@end example

Follows the description of the accepted parameters.
@table @option

@item server
It is the address of the RTMP server.

@item port
It is the number of the TCP port to use (by default is 1935).

@item app
It is the name of the application to acces. It usually corresponds to
the the path where the application is installed on the RTMP server
(e.g. @file{/ondemand/}, @file{/flash/live/}, etc.).

@item playpath
It is the path or name of the resource to play with reference to the
application specified in @var{app}, may be prefixed by "mp4:".

@end table

For example to read with @file{ffplay} a multimedia resource named
"sample" from the application "vod" from an RTMP server "myserver":
@example
ffplay rtmp://myserver/vod/sample
@end example

@section rtmp, rtmpe, rtmps, rtmpt, rtmpte

Real-Time Messaging Protocol and its variants supported through
librtmp.

Require the presence of the headers and library of librtmp during
configuration. You need to explicitely configure the build with
"--enable-librtmp". If enabled this will replace the native RTMP
protocol.

This protocol provides most client functions and a few server
functions needed to support RTMP, RTMP tunneled in HTTP (RTMPT),
encrypted RTMP (RTMPE), RTMP over SSL/TLS (RTMPS) and tunneled
variants of these encrypted types (RTMPTE, RTMPTS).

The required syntax is:
@example
@var{rtmp_proto}://@var{server}[:@var{port}][/@var{app}][/@var{playpath}] @var{options}
@end example

where @var{rtmp_proto} is one of the strings "rtmp", "rtmpt", "rtmpe",
"rtmps", "rtmpte", "rtmpts" corresponding to each RTMP variant, and
@var{server}, @var{port}, @var{app} and @var{playpath} have the same
meaning has specified for the RTMP native protocol.
@var{options} contains a list of space-separated options of the form
@var{key}=@var{val}.

See the manual page of librtmp (man 3 librtmp) for more information.

For example, to stream a file in real-time to an RTMP server using
@file{ffmpeg}:
@example
ffmpeg -re -i myfile -f flv rtmp://myserver/live/mystream
@end example

To play the same stream using @file{ffplay}:
@example
ffplay "rtmp://myserver/live/mystream live=1"
@end example

@section rtp

Real-Time Protocol.

@section tcp

Trasmission Control Protocol.

@section udp

User Datagram Protocol.

@c man end PROTOCOLS