ezstream/doc/ezstream.1.in.in

.\" Copyright (c) 2007, 2009, 2015, 2017 Moritz Grimm <mgrimm@mrsserver.net>
.\"
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.\" it under the terms of the GNU General Public License version 2 as
.\" published by the Free Software Foundation.
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.Dd @BUILD_DATE@
.Dt EZSTREAM 1
.Os @PACKAGE_NAME@ @PACKAGE_VERSION@
.Sh NAME
.Nm ezstream
.Nd source client for Icecast with external de-/encoder support
.Sh SYNOPSIS
.Nm
.Bk -words
.Op Fl hqrVv
.Fl c Ar configfile
.Op Fl p Ar pidfile
.Ek
.Nm
.Bk -words
.Fl s Ar file
.Ek
.Sh DESCRIPTION
The
.Nm
utility is a source client for the Icecast media streaming server.
In its basic mode of operation, it streams media files and data from standard
input
.Qq as-is
\(em such as Ogg Vorbis, Ogg Theora and MP3 \(em to a server.
It can also use various external decoders and encoders to re-encode from one
format to another, and stream the result.
The only requirement is that the external programs support writing to or
reading from standard input, and can be used from the command line.
.Ss Command line arguments
.Bl -tag -width Ds
.It Fl c Ar configfile
Use the XML configuration in
.Ar configfile .
.It Fl h
Print a summary of available command line arguments with short descriptions
and exit.
.It Fl p Ar pidfile
Write the
.Nm
process ID
.Pq a single number
to
.Ar pidfile .
The file will be written even when it already exists.
A file lock is maintained until the main
.Nm
process terminates.
If the file cannot be written for any reason,
.Nm
will log this, but not consider it a fatal error.
.It Fl q
Be more quiet.
Suppress the output that external programs send to standard error.
.It Fl r
Maintain a line of real-time status information about the stream on standard
output.
.Po
Implies
.Fl q .
.Pc
.It Fl s Ar file
Run
.Nm
as a line-based shuffling utility.
If a
.Ar playlist
argument of
.Dq -
is given, a list of media file names is read from standard input
instead of an input file.
After successfully reading the entire list, it is shuffled and printed to
standard output, and
.Nm
will exit.
.It Fl V
Print the
.Nm
version number and exit.
.It Fl v
Increase logging verbosity.
May be used up to three times to also include debug logging output.
.El
.Ss Runtime control
On POSIX systems,
.Nm
offers limited runtime control via signals.
By sending a signal to the ezstream process, e.g. with the
.Xr kill 1
utility, a certain action will be triggered.
.Bl -tag -width -Ds
.It Cd SIGHUP
Rereads the playlist file after the track that is currently streamed.
If the playlist is not to be shuffled,
.Nm
attempts to find the previously streamed file and continue with the one
following it, or restarts from the beginning of the list otherwise.
.It Cd SIGUSR1
Skips the currently playing track and moves on to the next in playlist mode, or
restarts the current track when streaming a single file.
.It Cd SIGUSR2
Triggers rereading of metadata for the stream by running the program or script
specified in
.Li \&<metadata_progname/\&>
.Pq see below.
This is the only meaningful signal when streaming from standard input.
.El
.Pp
.Sh CONFIGURATION FILE SYNTAX
The
.Nm
utility uses a simple XML configuration file format.
It has a tree-like structure and is made up of
.Em XML elements .
Of all the possible XML features, only regular elements that contain text or
other elements, and comments, appear in an
.Nm
configuration file.
.Pp
Each element in the configuration file consists of a
.Em start tag ,
its content, and an
.Em end tag .
For example:
.Pp
.Dl \&<filename\&>playlist.m3u<\&/filename\&>
.Dl \&<\&!-- XML comments look like this. --\&>
.Sh XML CONFIGURATION
In this section, each available element is listed and described.
Note that for this purpose, elements are introduced in their short, i.e. empty
form.
In the configuration file, they need to be used as
.Em start tag + content + end tag ,
like in the introductory example shown above.
.Ss Root element
.Bl -tag -width -Ds
.It Sy \&<ezstream\ /\&>
.Pq Mandatory.
The configuration file's root element.
It contains all other configuration elements:
.Pp
.El
.Ss Server block
.Bl -tag -width -Ds
.It Sy \&<server\ /\&>
.Pq Mandatory.
This element contains the entire server configuration as child elements.
Its parent is the
.Sy \&<ezstream\ /\&>
element.
.El
.Ss Server configuration
.Bl -tag -width -Ds
.It Sy \&<protocol\ /\&>
Transport protocol used to stream to the server:
.Pp
.Bl -tag -width HTTPS -compact
.It Ar HTTP
Unencrypted HTTP (the default).
.It Ar HTTPS
HTTP over TLS.
.El
.It Sy \&<hostname\ /\&>
.Pq Mandatory.
The FQDN host name or IP address of the server.
.It Sy \&<port\ /\&>
Port number on which the server is listening.
.Pp
Default:
.Ar 8000
.It Sy \&<user\ /\&>
User to authenticate as on the server.
.Pp
Default:
.Ar source
.It Sy \&<password\ /\&>
.Pq Mandatory.
Password to authenticate with on the server.
.It Sy \&<tls\ /\&>
Configure the TLS encryption requirement for the server connection.
Possible values are:
.Pp
.Bl -tag -width 0|NO|FALSE -compact
.It Ar None
No TLS encryption will be attempted.
.It Ar May
Opportunistic TLS encryption may be used, if the server supports it
.Pq the default .
.It Ar Required
TLS encryption is required.
This is the only setting that is providing security against both passive and
active attackers.
.El
.It Sy \&<tls_cipher_suite\ /\&>
Configure allowed cipher suites for TLS.
.Pp
For example (modern cipher suites, PFS, no deprecated algorithms):
.Sy HIGH:!kRSA:!kECDH:!DH:!PKS:!aNULL:!eNULL:!3DES:!MD5:!SHA:!TLSv1 .
.Pp
Default:
.Em libshout default cipher suite
.It Sy \&<ca_dir\ /\&>
Directory in which OpenSSL finds root CA certificates for validating the
.Ar HTTPS
server identity.
.Pp
Default:
.Em system default
.It Sy \&<ca_file\ /\&>
Path of a root CA bundle file for validating the
.Ar HTTPS
server identity.
.Pp
Default:
.Em system default
.It Sy \&<client_cert\ /\&>
X.503 client certificate and key
.Pq in PEM format containing both certificate and key in the same file
for authentication on an
.Ar HTTPS
server.
.Pp
Default:
.Em no client certificate authentication
.It Sy \&<reconnect_attempts\ /\&>
Number of reconnect attempts in case of connection issues with the server,
or 0
.Pq zero
for trying indefinitely (the default).
.El
.Ss Stream block
.Bl -tag -width -Ds
.It Sy \&<stream\ /\&>
.Pq Mandatory.
This element contains the entire stream configuration as child elements.
Its parent is the
.Sy \&<ezstream\ /\&>
element.
.El
.Ss Stream configuration
.Bl -tag -width -Ds
.It Sy \&<mountpoint\ /\&>
.Pq Mandatory.
Stream mountpoint on the server.
.It Sy \&<name\ /\&>
Informational name of the broadcast.
.Pp
Default:
.Em none
.It Sy \&<url\ /\&>
Informational URL associated with the broadcast, e.g. the web site.
.Pp
Default:
.Em none
.It Sy \&<genre\ /\&>
Informational genre of the broadcast.
.Pp
Default:
.Em none
.It Sy \&<description\ /\&>
Informational description of the broadcast.
.Pp
Default:
.Em none
.It Sy \&<quality\ /\&>
Informational quality setting of the VBR broadcast.
.Pp
Default:
.Em none
.It Sy \&<bitrate\ /\&>
Informational bitrate setting of the CBR broadcast.
.Pp
Default:
.Em none
.It Sy \&<samplerate\ /\&>
Informational sample rate of the broadcast audio.
.Pp
Default:
.Em none
.It Sy \&<channels\ /\&>
Informational number of audio channels of the broadcast.
.Pp
Default:
.Em none
.It Sy \&<server_public\ /\&>
Boolean setting of whether the broadcast may be listed in a public YP
directory, or not.
.Pp
.Bl -tag -width 0|NO|FALSE -compact
.It Ar 0|No|False
The broadcast is private (the default).
.It Ar 1|Yes|True
The broadcast is public.
.El
.It Sy \&<format\ /\&>
.Pq Mandatory.
The stream format.
.Pp
.Bl -tag -width VORBIS -compact
.It Ar Vorbis
Ogg Vorbis audio format
.It Ar MP3
MP3 audio format
.It Ar Theora
Ogg Theora video format
.El
.It Sy \&<encoder\ /\&>
Set the encoder by its configured symbolic name
.Pq see below ,
which should be used to (re)encode the stream.
Not configuring an encoder makes
.Nm
stream input media files as-is.
.Pp
The configured encoder's output stream format must match what is configured
in
.Sy \&<format\ /\&> .
.El
.Ss Media block
.Bl -tag -width -Ds
.It Sy \&<media\ /\&>
.Pq Mandatory.
This element contains the entire input media configuration as child elements.
Its parent is the
.Sy \&<ezstream\ /\&>
element.
.El
.Ss Media configuration
.Bl -tag -width -Ds
.It Sy \&<type\ /\&>
Configure the input media type:
.Pp
.Bl -tag -width AUTODETECT -compact
.It Ar autodetect
Attempt to autodetect, whether the input is a playlist, or a single media
file.
Playlists are detected by their
.Dq Li .m3u
and
.Dq Li .txt
file name extensions.
.Pq This is the default.
.It Ar file
The input is one single media file.
.It Ar playlist
The input is a playlist.
Playlists are a newline-delimited list of media file path names.
Comments in playlists are introduced by a
.Sq Li #
sign at the beginning of a line and ignored by
.Nm .
.It Ar program
The input is an executable
.Dq Playlist Program .
See
.Xr SCRIPTING
for more information.
.It Ar stdin
The input is read from standard input.
.El
.It Sy \&<filename\ /\&>
The input media file name; mandatory for all but the
.Ar stdin
type.
.It Sy \&<shuffle\ /\&>
Boolean setting of whether the
.Ar playlist
type media should be shuffled, or not.
.Pp
.Bl -tag -width 0|NO|FALSE -compact
.It Ar 0|No|False
Stream the playlist content sequentially (the default).
.It Ar 1|Yes|True
Shuffle the playlist prior to streaming its content.
.El
.It Sy \&<stream_once\ /\&>
Boolean setting of whether
.Nm
should exit after streaming its media input, or start over.
.Pp
.Bl -tag -width 0|NO|FALSE -compact
.It Ar 0|No|False
Attempt to start over whenever the end of the media input is reached (the
default).
.It Ar 1|Yes|True
After streaming all media input, exit.
.El
.El
.Ss Metadata block
.Bl -tag -width -Ds
.It Sy \&<metadata\ /\&>
This element contains the entire metadata configuration as child elements.
Its parent is the
.Sy \&<ezstream\ /\&>
element.
.El
.Ss Metadata configuration
.Bl -tag -width -Ds
.It Sy \&<program\ /\&>
Set an executable
.Dq Metadata Program
to be queried for all metadata on
.Sy SIGUSR2
or whenever a new track begins.
See
.Xr SCRIPTING
for more information.
.Pp
Default:
.Em use metadata as contained in media files
.It Sy \&<format_str\ /\&>
Set the format of the string that should be used for the
.Sq Li @M@
placeholder, when quering for metadata from an executable.
.Pp
Default:
.Li @a@ - @t@
.It Sy \&<refresh_interval\ /\&>
Configure a time interval for additional metadata updates via a
.Dq Metadata Program :
.Pp
.Bl -tag -width -1 -compact
.It Ar -1
Do not trigger any additional metadata updates (the default).
.It Ar 0
Trigger metadata updates at the highest reasonable frequency.
.It Ar \&>0
Configure the time
.Pq in seconds
in between additional metadata updates.
.El
.It Sy \&<normalize_strings\ /\&>
Boolean setting of whether metadata strings should have excess whitespace
removed, or not.
.Pp
.Bl -tag -width 0|NO|FALSE -compact
.It Ar 0|No|False
Use metadata strings as-is (the default).
.It Ar 1|Yes|True
Trim leading and trailing whitespace, as well as remove excess whitespace
in case that there is more than one in sequence.
.El
.It Sy \&<no_updates\ /\&>
Boolean setting of whether metadata updates should be suppressed altogether,
or not.
.Pp
.Bl -tag -width 0|NO|FALSE -compact
.It Ar 0|No|False
Update metadata in the usual manner (the default).
.It Ar 1|Yes|True
Disable all metadata updates, and keep existing metadata in streams untouched.
.El
.El
.Ss Decoders block
.Bl -tag -width -Ds
.It Sy \&<decoders\ /\&>
This element contains all decoder blocks as child elements.
Its parent is the
.Sy \&<ezstream\ /\&>
element.
.El
.Ss Decoder block
.Bl -tag -width -Ds
.It Sy \&<decoder\ /\&>
This element contains all configuration of a single decoder.
Its parent is the
.Sy \&<decoders\ /\&>
element.
.Pp
Many decoders can be configured, but a filename extension can only be
associated with one decoder.
.El
.Ss Decoder configuration
.Bl -tag -width -Ds
.It Sy \&<name\ /\&>
Set the name of the decoder configuration.
Choosing a meaningful, unique name is beneficial for logging and debugging.
.Pp
Default:
.Em autoincrementing index
.It Sy \&<program\ /\&>
.Pq Mandatory.
Set the full command line to decode a media input file, represented by the
.Sq @T@
placeholder, into a
.Dq canonical internal format
on standard output.
.Pp
The canonical format should be the same for all configured decoders, e.g. RAW
audio with a specific signedness, bitrate, and samplerate that can be
consumed by encoders.
.Pp
For exotic use cases, metadata placeholders may be used here.
.Pp
Example:
.Dl \&<program\&>oggdec -R -o - @T@\&</program\&>
.It Sy \&<file_ext\ /\&>
.Pq Mandatory.
Set a filename extension to be associated with this decoder.
.Pp
It is possible to specify more than one
.Sy \&<file_ext\ /\&>
element per decoder to associate more than one file extension to the same
decoder.
.El
.Ss Encoders block
.Bl -tag -width -Ds
.It Sy \&<encoders\ /\&>
This element contains all encoder blocks as child elements.
Its parent is the
.Sy \&<ezstream\ /\&>
element.
.El
.Ss Encoder block
.Bl -tag -width -Ds
.It Sy \&<encoder\ /\&>
This element contains all configuration of a single encoder.
Its parent is the
.Sy \&<encoders\ /\&>
element.
.Pp
Many encoders can be configured.
.El
.Ss Encoder configuration
.Bl -tag -width -Ds
.It Sy \&<name\ /\&>
.Pq Mandatory.
Set the name of the encoder configuration, to be referenced in the
.Sy \&<stream\ /\&>
block in case (re)encoding is desired.
.Pp
The name is case-aware, but not case-sensitive.
.It Sy \&<format\ /\&>
.Pq Mandatory.
Stream format produced by this encoder.
This must be one of the available stream formats as specified for the
.Sy \&<stream\ /\&>
block.
.It Sy \&<program\ /\&>
.Pq Mandatory.
Set the full command line to encode
.Dq canonical internal format
from standard input into a supported stream format on standard output.
.Pp
Metadata placeholders may be used here.
.Pp
Example:
.Dl \&<program\&>oggenc -r -q 1.5 -t @M@ -\&</program\&>
.El
.Sh SCRIPTING
The
.Nm
utility provides hooks for externally controlled playlist and metadata
management.
This is done by running external programs or scripts that need to behave in
ways explained here.
.Ss Common Rules
.Bl -dash -compact
.It
The program must be an executable file.
.It
The program must write one line to standard output and exit.
.It
The program must not require arbitrary command line options to function.
A wrapper script must be used if there is no other way.
.El
.Ss Playlist Programs
.Bl -dash -compact
.It
The program must return only filenames, with one filename per execution.
.It
The program should not return an empty line unless
.Nm
is supposed to know that the end of the playlist has been reached.
This is significant when the
.Li \&<stream_once/\&>
option is enabled.
.El
.Ss Metadata Programs
.Bl -dash -compact
.It
The program must not return anything (just a newline character is okay) if it
is called by
.Nm
with a command line argument that the program does not support.
.It
When called without command line arguments, the program should return a
complete string that should be used for metadata.
.It
When called with the command line argument
.Qq Li artist ,
the program should return only the artist information of the metadata.
.Pq Optional.
.It
When called with the command line argument
.Qq Li title ,
the program should return only the title information of the metadata.
.Pq Optional.
.It
The supplied metadata must be encoded in UTF-8.
.El
.Sh METADATA
The main tool for handling metadata with
.Nm
is placeholders in decoder and encoder commands that are replaced with real
content during runtime.
.Pp
.Em Note:
All placeholders are replaced with content enclosed in single quotes, with
escaped single quote and backslash characters in between, so that
interpretation by the shell does not occur.
.Em \&Do not add any additional quoting!
.Ss Metadata Placeholders
.Bl -tag -width -Ds
.It Sy @T@
Replaced with the media file name.
Required in
.Li /ezstream/decoders/decoder/program .
Available in
.Li /ezstream/metadata/format_str .
.It Sy @M@
Replaced with a metadata string.
.Pq See below for a detailed explanation.
Available in
.Li /ezstream/decoders/decoder/program
and
.Li /ezstream/encoders/encoder/program .
.It Sy @a@
Replaced with the artist information.
Available in
.Li /ezstream/decoders/decoder/program ,
.Li /ezstream/encoders/encoder/program
and
.Li /ezstream/metadata/format_str .
.It Sy @t@
Replaced with the title information.
Available in
.Li /ezstream/decoders/decoder/program ,
.Li /ezstream/encoders/encoder/program
and
.Li /ezstream/metadata/format_str .
.It Sy @b@
Replaced with the album information.
Available in
.Li /ezstream/decoders/decoder/program ,
.Li /ezstream/encoders/encoder/program
and
.Li /ezstream/metadata/format_str .
.It Sy @s@
Replaced with the string returned by
.Li /ezstream/metadata/program
when called without any command line arguments.
Available only in
.Li /ezstream/metadata/format_str .
.El
.Ss The @M@ Placeholder
While all other placeholders are simply replaced with whatever data they are
associated with,
.Sq Li @M@
is context-sensitive.
The logic used by
.Nm
is the following:
.Bd -literal -offset indent
If ('@M@ is present')
    If (/ezstream/metadata/program AND /ezstream/metadata/format_str)
        Replace with format string result.
    Else
        If (NOT /ezstream/metadata/program AND '@t@ is present')
            Replace with empty string.
        else
            Replace with generated metadata string.
        Endif
    Endif
Endif
.Ed
.Pp
The generated metadata string for
.Sq Li @M@
is of the format
.Dq Em Artist - Title ,
if both artist and title information is available.
If one of the two is missing, the available one is displayed without a leading
or trailing dash, e.g. just
.Dq Em Artist .
If neither artist nor title are available, the name of the media file \(em
without its file extension \(em is used.
.Ss Metadata Caveats
It is possible to generate strange results with odd combinations of
placeholders, external metadata programs and updates during runtime via
.Sy SIGUSR2 .
If things start to become just confusing, simplify.
.Pp
Metadata updates during runtime are done with a eccentric feature of libshout.
Additional metadata information that is already present in the stream sent via
.Nm
is usually destroyed and replaced with the new data.
It is not possible to properly discern between artist and title information,
which means that anything set with the
.Sy SIGUSR2
feature will continue to end up entirely in the
.Qq Em Title
field of a stream.
.Pp
Additional limitations in Icecast may apply as well, where one historic
example is that of all possible Ogg-based streams, only Ogg Vorbis can have
its metadata manipulated.
.Pp
The ID3v1 tags
.Pq relevant when streaming in MP3 format
do not specify any character encoding, so
.Nm
operates in a manner of
.Dq best effort .
In case of encoding issues, it may help to explicitly set a codeset to work
with via the
.Ev LC_CTYPE
environment variable, as
.Nm
assumes ID3v1 tags to be in the user's current locale.
Note that, even though support for different locales is provided by
.Nm ,
Icecast itself and the listening clients also have a say in the matter.
The only way to ensure consistent results with metadata in non-Ogg streams is
to use only the characters available in the ISO-8859-1 codeset.
.Pp
External encoders may put additional, and possibly artificial, restrictions on
valid characters in metadata.
.Sh FILES
.Bl -tag -width "!!EXAMPLES_DIR!!" -compact
.It Pa !!EXAMPLES_DIR!!
Directory containing example configuration files for various uses of
.Nm ,
as well as example playlist and metadata scripts.
.El
.Sh SEE ALSO
.Xr ezstream-file.sh 1
.Sh AUTHORS
.Nm
was written by:
.Pp
.An Ed Zaleski Aq oddsock@oddsock.org
.An Moritz Grimm Aq mgrimm@mrsserver.net
.Pp
.An -nosplit
This manual was written by
.An Moritz Grimm .