ffserver is a streaming server for both audio and video.
It supports several live feeds, streaming from files and time shifting
on live feeds. You can seek to positions in the past on each live
feed, provided you specify a big enough feed storage.
ffserver is configured through a configuration file, which
is read at startup. If not explicitly specified, it will read from
ffserver receives prerecorded files or FFM streams from some
ffmpeg instance as input, then streams them over
ffserver instance will listen on some port as specified
in the configuration file. You can launch one or more instances of
ffmpeg and send one or more FFM streams to the port where
ffserver is expecting to receive them. Alternately, you can make
ffserver launch such
ffmpeg instances at startup.
Input streams are called feeds, and each one is specified by a
<Feed> section in the configuration file.
For each feed you can have different output streams in various
formats, each one specified by a
<Stream> section in the
ffserver works by forwarding streams encoded by
ffmpeg, or pre-recorded streams which are read from disk.
ffserver acts as an HTTP server, accepting POST
ffmpeg to acquire the stream to publish, and
serving HTTP clients GET requests with the stream media content.
A feed is an FFM stream created by
ffmpeg, and sent to
a port where
ffserver is listening.
Each feed is identified by a unique name, corresponding to the name
of the resource published on
ffserver, and is configured by
Feed section in the configuration file.
The feed publish URL is given by:
where ffserver_ip_address is the IP address of the machine where
ffserver is installed, http_port is the port number of
the HTTP server (configured through the ‘Port’ option), and
feed_name is the name of the corresponding feed defined in the
Each feed is associated to a file which is stored on disk. This stored file is used to allow to send pre-recorded data to a player as fast as possible when new content is added in real-time to the stream.
A "live-stream" or "stream" is a resource published by
ffserver, and made accessible through the HTTP protocol to
A stream can be connected to a feed, or to a file. In the first case,
the published stream is forwarded from the corresponding feed
generated by a running instance of
ffmpeg, in the second
case the stream is read from a pre-recorded file.
Each stream is identified by a unique name, corresponding to the name
of the resource served by
ffserver, and is configured by
Stream section in the configuration file.
The stream access URL is given by:
stream_name is the name of the corresponding stream defined in
the configuration file. options is a list of options specified
after the URL which affects how the stream is served by
In case the stream is associated to a feed, the encoding parameters
must be configured in the stream configuration. They are sent to
ffmpeg when setting up the encoding. This allows
ffserver to define the encoding parameters used by
ffmpeg ‘override_ffserver’ commandline option
allows to override the encoding parameters set by the server.
Multiple streams can be connected to the same feed.
For example, you can have a situation described by the following graph:
_________ __________ | | | | ffmpeg 1 -----| feed 1 |-----| stream 1 | \ |_________|\ |__________| \ \ \ \ __________ \ \ | | \ \| stream 2 | \ |__________| \ \ _________ __________ \ | | | | \| feed 2 |-----| stream 3 | |_________| |__________| _________ __________ | | | | ffmpeg 2 -----| feed 3 |-----| stream 4 | |_________| |__________| _________ __________ | | | | | file 1 |-----| stream 5 | |_________| |__________|
FFM and FFM2 are formats used by ffserver. They allow storing a wide variety of video and audio streams and encoding options, and can store a moving time segment of an infinite movie or a whole movie.
FFM is version specific, and there is limited compatibility of FFM files generated by one version of ffmpeg/ffserver and another version of ffmpeg/ffserver. It may work but it is not guaranteed to work.
FFM2 is extensible while maintaining compatibility and should work between differing versions of tools. FFM2 is the default.
ffserver supports an HTTP interface which exposes the
current status of the server.
Simply point your browser to the address of the special status stream specified in the configuration file.
For example if you have:
<Stream status.html> Format status # Only allow local people to get the status ACL allow localhost ACL allow 192.168.0.0 192.168.255.255 </Stream>
then the server will post a page with the status information when the special stream ‘status.html’ is requested.
As a simple test, just run the following two command lines where INPUTFILE is some file which you can decode with ffmpeg:
ffserver -f doc/ffserver.conf & ffmpeg -i INPUTFILE http://localhost:8090/feed1.ffm
At this point you should be able to go to your Windows machine and fire up Windows Media Player (WMP). Go to Open URL and enter
You should (after a short delay) see video and hear audio.
WARNING: trying to stream test1.mpg doesn’t work with WMP as it tries to transfer the entire file before starting to play. The same is true of AVI files.
You should edit the ffserver.conf file to suit your needs (in terms of frame rates etc). Then install ffserver and ffmpeg, write a script to start them up, and off you go.
You can replay video from .ffm files that was recorded earlier. However, there are a number of caveats, including the fact that the ffserver parameters must match the original parameters used to record the file. If they do not, then ffserver deletes the file before recording into it. (Now that I write this, it seems broken).
You can fiddle with many of the codec choices and encoding parameters, and there are a bunch more parameters that you cannot control. Post a message to the mailing list if there are some ’must have’ parameters. Look in ffserver.conf for a list of the currently available controls.
It will automatically generate the ASX or RAM files that are often used in browsers. These files are actually redirections to the underlying ASF or RM file. The reason for this is that the browser often fetches the entire file before starting up the external viewer. The redirection files are very small and can be transferred quickly. [The stream itself is often ’infinite’ and thus the browser tries to download it and never finishes.]
* When you connect to a live stream, most players (WMP, RA, etc) want to buffer a certain number of seconds of material so that they can display the signal continuously. However, ffserver (by default) starts sending data in realtime. This means that there is a pause of a few seconds while the buffering is being done by the player. The good news is that this can be cured by adding a ’?buffer=5’ to the end of the URL. This means that the stream should start 5 seconds in the past – and so the first 5 seconds of the stream are sent as fast as the network will allow. It will then slow down to real time. This noticeably improves the startup experience.
You can also add a ’Preroll 15’ statement into the ffserver.conf that will add the 15 second prebuffering on all requests that do not otherwise specify a time. In addition, ffserver will skip frames until a key_frame is found. This further reduces the startup delay by not transferring data that will be discarded.
It turns out that (on my machine at least) the number of frames successfully grabbed is marginally less than the number that ought to be grabbed. This means that the timestamp in the encoded data stream gets behind realtime. This means that if you say ’Preroll 10’, then when the stream gets 10 or more seconds behind, there is no Preroll left.
Fixing this requires a change in the internals of how timestamps are handled.
Yes (subject to the limitation outlined above). Also note that whenever you start ffserver, it deletes the ffm file (if any parameters have changed), thus wiping out what you had recorded before.
The format of the
?date=xxxxxx is fairly flexible. You should use one
of the following formats (the ’T’ is literal):
* YYYY-MM-DDTHH:MM:SS (localtime) * YYYY-MM-DDTHH:MM:SSZ (UTC)
You can omit the YYYY-MM-DD, and then it refers to the current day. However note that ‘?date=16:00:00’ refers to 16:00 on the current day – this may be in the future and so is unlikely to be useful.
You use this by adding the ?date= to the end of the URL for the stream. For example: ‘http://localhost:8080/test.asf?date=2002-07-26T23:05:00’.
All the numerical options, if not specified otherwise, accept a string representing a number as input, which may be followed by one of the SI unit prefixes, for example: ’K’, ’M’, or ’G’.
If ’i’ is appended to the SI unit prefix, the complete prefix will be interpreted as a unit prefix for binary multiplies, which are based on powers of 1024 instead of powers of 1000. Appending ’B’ to the SI unit prefix multiplies the value by 8. This allows using, for example: ’KB’, ’MiB’, ’G’ and ’B’ as number suffixes.
Options which do not take arguments are boolean options, and set the corresponding value to true. They can be set to false by prefixing the option name with "no". For example using "-nofoo" will set the boolean option with name "foo" to false.
Some options are applied per-stream, e.g. bitrate or codec. Stream specifiers are used to precisely specify which stream(s) a given option belongs to.
A stream specifier is a string generally appended to the option name and
separated from it by a colon. E.g.
-codec:a:1 ac3 contains the
a:1 stream specifier, which matches the second audio stream. Therefore, it
would select the ac3 codec for the second audio stream.
A stream specifier can match several streams, so that the option is applied to all
of them. E.g. the stream specifier in
-b:a 128k matches all audio
An empty stream specifier matches all streams. For example,
-codec: copy would copy all the streams without reencoding.
Possible forms of stream specifiers are:
Matches the stream with this index. E.g.
-threads:1 4 would set the
thread count for the second stream to 4.
stream_type is one of following: ’v’ for video, ’a’ for audio, ’s’ for subtitle, ’d’ for data, and ’t’ for attachments. If stream_index is given, then it matches stream number stream_index of this type. Otherwise, it matches all streams of this type.
If stream_index is given, then it matches the stream with number stream_index in the program with the id program_id. Otherwise, it matches all streams in the program.
Matches the stream by a format-specific ID.
These options are shared amongst the ff* tools.
Show help. An optional parameter may be specified to print help about a specific item. If no argument is specified, only basic (non advanced) tool options are shown.
Possible values of arg are:
Print advanced tool options in addition to the basic tool options.
Print complete list of options, including shared and private options for encoders, decoders, demuxers, muxers, filters, etc.
Print detailed information about the decoder named decoder_name. Use the ‘-decoders’ option to get a list of all decoders.
Print detailed information about the encoder named encoder_name. Use the ‘-encoders’ option to get a list of all encoders.
Print detailed information about the demuxer named demuxer_name. Use the ‘-formats’ option to get a list of all demuxers and muxers.
Print detailed information about the muxer named muxer_name. Use the ‘-formats’ option to get a list of all muxers and demuxers.
Print detailed information about the filter name filter_name. Use the ‘-filters’ option to get a list of all filters.
Show available formats.
Show all codecs known to libavcodec.
Note that the term ’codec’ is used throughout this documentation as a shortcut for what is more correctly called a media bitstream format.
Show available decoders.
Show all available encoders.
Show available bitstream filters.
Show available protocols.
Show available libavfilter filters.
Show available pixel formats.
Show available sample formats.
Show channel names and standard channel layouts.
Show recognized color names.
Set the logging level used by the library. Adding "repeat+" indicates that repeated log output should not be compressed to the first line and the "Last message repeated n times" line will be omitted. "repeat" can also be used alone. If "repeat" is used alone, and with no prior loglevel set, the default loglevel will be used. If multiple loglevel parameters are given, using ’repeat’ will not change the loglevel. loglevel is a number or a string containing one of the following values:
Show nothing at all; be silent.
Only show fatal errors which could lead the process to crash, such as and assert failure. This is not currently used for anything.
Only show fatal errors. These are errors after which the process absolutely cannot continue after.
Show all errors, including ones which can be recovered from.
Show all warnings and errors. Any message related to possibly incorrect or unexpected events will be shown.
Show informative messages during processing. This is in addition to warnings and errors. This is the default value.
info, except more verbose.
Show everything, including debugging information.
By default the program logs to stderr, if coloring is supported by the
terminal, colors are used to mark errors and warnings. Log coloring
can be disabled setting the environment variable
NO_COLOR, or can be forced setting
the environment variable
The use of the environment variable
NO_COLOR is deprecated and
will be dropped in a following FFmpeg version.
Dump full command line and console output to a file named
program-YYYYMMDD-HHMMSS.log in the current
This file can be useful for bug reports.
It also implies
Setting the environment variable
FFREPORT to any value has the
same effect. If the value is a ’:’-separated key=value sequence, these
options will affect the report; options values must be escaped if they
contain special characters or the options delimiter ’:’ (see the
“Quoting and escaping” section in the ffmpeg-utils manual). The
following option is recognized:
set the file name to use for the report;
%p is expanded to the name
of the program,
%t is expanded to a timestamp,
%% is expanded
to a plain
Errors in parsing the environment variable are not fatal, and will not appear in the report.
Allows setting and clearing cpu flags. This option is intended for testing. Do not use it unless you know what you’re doing.
ffmpeg -cpuflags -sse+mmx ... ffmpeg -cpuflags mmx ... ffmpeg -cpuflags 0 ...
Possible flags for this option are:
Set OpenCL environment options. This option is only available when
FFmpeg has been compiled with
options must be a list of key=value option pairs separated by ’:’. See the “OpenCL Options” section in the ffmpeg-utils manual for the list of supported options.
These options are provided directly by the libavformat, libavdevice and libavcodec libraries. To see the list of available AVOptions, use the ‘-help’ option. They are separated into two categories:
These options can be set for any container, codec or device. Generic options are listed under AVFormatContext options for containers/devices and under AVCodecContext options for codecs.
These options are specific to the given container, device or codec. Private options are listed under their corresponding containers/devices/codecs.
For example to write an ID3v2.3 header instead of a default ID3v2.4 to an MP3 file, use the ‘id3v2_version’ private option of the MP3 muxer:
ffmpeg -i input.flac -id3v2_version 3 out.mp3
All codec AVOptions are per-stream, and thus a stream specifier should be attached to them.
Note: the ‘-nooption’ syntax cannot be used for boolean AVOptions, use ‘-option 0’/‘-option 1’.
Note: the old undocumented way of specifying per-stream AVOptions by prepending v/a/s to the options name is now obsolete and will be removed soon.
Read configuration file ‘configfile’. If not specified it will read by default from ‘/etc/ffserver.conf’.
Enable no-launch mode. This option disables all the
directives within the various
<Feed> sections. Since
ffserver will not launch any
ffmpeg instances, you
will have to launch them manually.
Enable debug mode. This option increases log verbosity, and directs log messages to stdout. When specified, the ‘CustomLog’ option is ignored.
ffserver reads a configuration file containing global
options and settings for each stream and feed.
The configuration file consists of global options and dedicated sections, which must be introduced by "<SECTION_NAME ARGS>" on a separate line and must be terminated by a line in the form "</SECTION_NAME>". ARGS is optional.
Currently the following sections are recognized: ‘Feed’, ‘Stream’, ‘Redirect’.
A line starting with
# is ignored and treated as a comment.
Name of options and sections are case-insensitive.
An ACL (Access Control List) specifies the address which are allowed to access a given stream, or to write a given feed.
It accepts the folling forms
ACL ALLOW <address> ACL DENY <address>
ACL ALLOW <first_address> <last_address> ACL DENY <first_address> <last_address>
You can repeat the ACL allow/deny as often as you like. It is on a per stream basis. The first match defines the action. If there are no matches, then the default is the inverse of the last ACL statement.
Thus ’ACL allow localhost’ only allows access from localhost. ’ACL deny 22.214.171.124 126.96.36.199’ would deny the whole of network 1 and allow everybody else.
Set TCP port number on which the HTTP/RTSP server is listening. You must select a different port from your standard HTTP web server if it is running on the same computer.
If not specified, no corresponding server will be created.
Set address on which the HTTP/RTSP server is bound. Only useful if you have several network interfaces.
Set number of simultaneous HTTP connections that can be handled. It has to be defined before the ‘MaxClients’ parameter, since it defines the ‘MaxClients’ maximum limit.
Default value is 2000.
Set number of simultaneous requests that can be handled. Since
ffserver is very fast, it is more likely that you will want
to leave this high and use ‘MaxBandwidth’.
Default value is 5.
Set the maximum amount of kbit/sec that you are prepared to consume when streaming to clients.
Default value is 1000.
Set access log file (uses standard Apache log file format). ’-’ is the standard output.
If not specified
ffserver will produce no log.
In case the commandline option ‘-d’ is specified this option is ignored, and the log is written to standard output.
Set no-daemon mode. This option is currently ignored since now
ffserver will always work in no-daemon mode, and is
A Feed section defines a feed provided to
Each live feed contains one video and/or audio sequence coming from an
ffmpeg encoder or another
ffserver. This sequence
may be encoded simultaneously with several codecs at several
A feed instance specification is introduced by a line in the form:
where FEED_FILENAME specifies the unique name of the FFM stream.
The following options are recognized within a Feed section.
Set the path where the feed file is stored on disk.
If not specified, the ‘/tmp/FEED.ffm’ is assumed, where FEED is the feed name.
If ‘ReadOnlyFile’ is used the file is marked as read-only and it will not be deleted or updated.
Truncate the feed file, rather than appending to it. By default
ffserver will append data to the file, until the maximum
file size value is reached (see ‘FileMaxSize’ option).
Set maximum size of the feed file in bytes. 0 means unlimited. The
M (2^20), and
G (2^30) are
Default value is 5M.
ffmpeg command when creating
args must be a sequence of arguments to be provided to an
ffmpeg instance. The first provided argument is ignored, and
it is replaced by a path with the same dirname of the
instance, followed by the remaining argument and terminated with a
path corresponding to the feed.
When the launched process exits,
ffserver will launch
another program instance.
In case you need a more complex
e.g. if you need to generate multiple FFM feeds with a single
ffmpeg instance, you should launch
ffmpeg by hand.
This option is ignored in case the commandline option ‘-n’ is specified.
Specify the list of IP address which are allowed or denied to write the feed. Multiple ACL options can be specified.
A Stream section defines a stream provided by
identified by a single name.
The stream is sent when answering a request containing the stream name.
A stream section must be introduced by the line:
where STREAM_NAME specifies the unique name of the stream.
The following options are recognized within a Stream section.
Encoding options are marked with the encoding tag, and they are
used to set the encoding parameters, and are mapped to libavcodec
encoding options. Not all encoding options are supported, in
particular it is not possible to set encoder private options. In order
to override the encoding options specified by
can use the
ffmpeg ‘override_ffserver’ commandline
Only one of the ‘Feed’ and ‘File’ options should be set.
Set the input feed. feed_name must correspond to an existing
feed defined in a
When this option is set, encoding options are used to setup the
encoding operated by the remote
Set the filename of the pre-recorded input file to stream.
When this option is set, encoding options are ignored and the input file content is re-streamed as is.
Set the format of the output stream.
Must be the name of a format recognized by FFmpeg. If set to ‘status’, it is treated as a status stream.
Set input format. If not specified, it is automatically guessed.
Set this to the number of seconds backwards in time to start. Note that most players will buffer 5-10 seconds of video, and also you need to allow for a keyframe to appear in the data stream.
Default value is 0.
Do not send stream until it gets the first key frame. By default
ffserver will send data immediately.
Set the number of seconds to run. This value set the maximum duration of the stream a client will be able to receive.
A value of 0 means that no limit is set on the stream duration.
Set ACL for the stream.
Set favicon (favourite icon) for the server status page. It is ignored for regular streams.
Set metadata corresponding to the option.
Set audio codec.
Set bitrate for the audio stream in kbits per second.
Set number of audio channels.
Set sampling frequency for audio. When using low bitrates, you should lower this frequency to 22050 or 11025. The supported frequencies depend on the selected audio codec.
Set generic option for audio stream.
Set preset for audio stream.
Set video codec.
Set bitrate for the video stream in kbits per second.
Set video bitrate range.
A range must be specified in the form minrate-maxrate, and specifies the ‘minrate’ and ‘maxrate’ encoding options expressed in kbits per second.
Set video bitrate tolerance in kbits per second.
Set video pixel format.
Set video ‘debug’ encoding option.
Set video ‘strict’ encoding option.
Set ratecontrol buffer size, expressed in KB.
Set number of video frames per second.
Set size of the video frame, must be an abbreviation or in the form WxH. See (ffmpeg-utils)video size syntax.
Default value is
Transmit only intra frames (useful for low bitrates, but kills frame rate).
If non-intra only, an intra frame is transmitted every VideoGopSize frames. Video synchronization can only begin at an intra frame.
Set video tag.
Set bitexact encoding flag.
Set simple IDCT algorithm.
Enable constant quality encoding, and set video qscale (quantization scale) value, expressed in n QP units.
Set video qmin/qmax.
Set video ‘qdiff’ encoding option.
Set ‘lumi_mask’/‘dark_mask’ encoding options.
Set generic option for video stream.
Set preset for video stream.
preset must be the path of a preset file.
A server status stream is a special stream which is used to show
statistics about the
It must be specified setting the option ‘Format’ to ‘status’.
A redirect section specifies where to redirect the requested URL to another page.
A redirect section must be introduced by the line:
where NAME is the name of the page which should be redirected.
It only accepts the option ‘URL’, which specify the redirection URL.
<Stream test.mjpg> Feed feed1.ffm Format mpjpeg VideoFrameRate 2 VideoIntraOnly NoAudio Strict -1 </Stream>
<Stream test.jpg> Feed feed1.ffm Format jpeg VideoFrameRate 2 VideoIntraOnly VideoSize 352x240 NoAudio Strict -1 </Stream>
<Stream test.swf> Feed feed1.ffm Format swf VideoFrameRate 2 VideoIntraOnly NoAudio </Stream>
<Stream test.asf> Feed feed1.ffm Format asf VideoFrameRate 15 VideoSize 352x240 VideoBitRate 256 VideoBufferSize 40 VideoGopSize 30 AudioBitRate 64 StartSendOnKey </Stream>
<Stream test.mp3> Feed feed1.ffm Format mp2 AudioCodec mp3 AudioBitRate 64 AudioChannels 1 AudioSampleRate 44100 NoVideo </Stream>
<Stream test.ogg> Feed feed1.ffm Title "Stream title" AudioBitRate 64 AudioChannels 2 AudioSampleRate 44100 NoVideo </Stream>
<Stream test.ra> Feed feed1.ffm Format rm AudioBitRate 32 NoVideo </Stream>
<Stream test.rm> Feed feed1.ffm Format rm AudioBitRate 32 VideoBitRate 128 VideoFrameRate 25 VideoGopSize 25 </Stream>
<Stream file.rm> File "/usr/local/httpd/htdocs/tlive.rm" NoAudio </Stream>
<Stream file.asf> File "/usr/local/httpd/htdocs/test.asf" NoAudio Author "Me" Copyright "Super MegaCorp" Title "Test stream from disk" Comment "Test comment" </Stream>
ffserver-all, the ‘doc/ffserver.conf’ example, ffmpeg, ffplay, ffprobe, ffmpeg-utils, ffmpeg-scaler, ffmpeg-resampler, ffmpeg-codecs, ffmpeg-bitstream-filters, ffmpeg-formats, ffmpeg-devices, ffmpeg-protocols, ffmpeg-filters
The FFmpeg developers.
For details about the authorship, see the Git history of the project
(git://source.ffmpeg.org/ffmpeg), e.g. by typing the command
git log in the FFmpeg source directory, or browsing the
online repository at http://source.ffmpeg.org.
Maintainers for the specific components are listed in the file ‘MAINTAINERS’ in the source code tree.