ffserver [options]
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 /etc/ffserver.conf.
ffserver receives prerecorded files or FFM streams from some ffmpeg instance as input, then streams them over RTP/RTSP/HTTP.
An 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 configuration file.
ffserver works by forwarding streams encoded by ffmpeg, or pre-recorded streams which are read from disk.
Precisely, ffserver acts as an HTTP server, accepting POST requests from ffmpeg to acquire the stream to publish, and serving RTSP clients or 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 a dedicated "Feed" section in the configuration file.
The feed publish URL is given by:
http://<ffserver_ip_address>:<http_port>/<feed_name>
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 HTTPPort option), and feed_name is the name of the corresponding feed defined in the configuration file.
Each feed is associated to a file which is stored on disk. This stored file is used 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 clients.
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 a dedicated "Stream" section in the configuration file.
The stream access HTTP URL is given by:
http://<ffserver_ip_address>:<http_port>/<stream_name>[<options>]
The stream access RTSP URL is given by:
http://<ffserver_ip_address>:<rtsp_port>/<stream_name>[<options>]
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 ffserver. http_port and rtsp_port are the HTTP and RTSP ports configured with the options HTTPPort and RTSPPort respectively.
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 the ffmpeg encoders.
The ffmpeg override_ffserver commandline option allows one 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
http://<linuxbox>:8090/test.asf
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 multiples, 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 streams.
An empty stream specifier matches all streams. For example, "-codec copy" or "-codec: copy" would copy all the streams without reencoding.
Possible forms of stream specifiers are:
Note that in ffmpeg, matching by metadata will only work properly for input files.
These options are shared amongst the ff* tools.
Possible values of arg are:
Note that the term 'codec' is used throughout this documentation as a shortcut for what is more correctly called a media bitstream format.
ffmpeg -sources pulse,server=192.168.0.4
ffmpeg -sinks pulse,server=192.168.0.4
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 AV_LOG_FORCE_NOCOLOR or NO_COLOR, or can be forced setting the environment variable AV_LOG_FORCE_COLOR. The use of the environment variable NO_COLOR is deprecated and will be dropped in a future FFmpeg version.
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; option 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 options are recognized:
For example, to output a report to a file named ffreport.log using a log level of 32 (alias for log level "info"):
FFREPORT=file=ffreport.log:level=32 ffmpeg -i input output
Errors in parsing the environment variable are not fatal, and will not appear in the report.
All FFmpeg tools will normally show a copyright notice, build options and library versions. This option can be used to suppress printing this information.
ffmpeg -cpuflags -sse+mmx ...
ffmpeg -cpuflags mmx ...
ffmpeg -cpuflags 0 ...
Possible flags for this option are:
When FFmpeg is configured with "--enable-opencl", the options for the global OpenCL context are set via -opencl_options. See the "OpenCL Options" section in the ffmpeg-utils manual for the complete list of supported options. Amongst others, these options include the ability to select a specific platform and device to run the OpenCL code on. By default, FFmpeg will run on the first device of the first platform. While the options for the global OpenCL context provide flexibility to the user in selecting the OpenCL device of their choice, most users would probably want to select the fastest OpenCL device for their system.
This option assists the selection of the most efficient configuration by identifying the appropriate device for the user's system. The built-in benchmark is run on all the OpenCL devices and the performance is measured for each device. The devices in the results list are sorted based on their performance with the fastest device listed first. The user can subsequently invoke ffmpeg using the device deemed most appropriate via -opencl_options to obtain the best performance for the OpenCL accelerated code.
Typical usage to use the fastest OpenCL device involve the following steps.
Run the command:
ffmpeg -opencl_bench
Note down the platform ID (pidx) and device ID (didx) of the first i.e. fastest device in the list. Select the platform and device using the command:
ffmpeg -opencl_options platform_idx=<pidx>:device_idx=<didx> ...
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:
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.
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 following 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 1.0.0.0 1.255.255.255' would deny the whole of network 1 and allow everybody else.
Port is the equivalent of HTTPPort and is deprecated.
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.
BindAddress is the equivalent of HTTPBindAddress and is deprecated.
Default value is 2000.
Default value is 5.
Default value is 1000.
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.
A Feed section defines a feed provided to ffserver.
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 resolutions.
A feed instance specification is introduced by a line in the form:
<Feed FEED_FILENAME>
where FEED_FILENAME specifies the unique name of the FFM stream.
The following options are recognized within a Feed section.
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.
Default value is 5M.
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 ffserver 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 ffmpeg configuration, 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.
A Stream section defines a stream provided by ffserver, and 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:
<Stream STREAM_NAME>
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 ffserver, you can use the ffmpeg override_ffserver commandline option.
Only one of the Feed and File options should be set.
When this option is set, encoding options are used to setup the encoding operated by the remote ffmpeg process.
When this option is set, encoding options are ignored and the input file content is re-streamed as is.
Must be the name of a format recognized by FFmpeg. If set to status, it is treated as a status stream.
Default value is 0.
A value of 0 means that no limit is set on the stream duration.
A range must be specified in the form minrate-maxrate, and specifies the minrate and maxrate encoding options expressed in kbits per second.
Default value is "160x128".
preset must be the path of a preset file.
Server status stream
A server status stream is a special stream which is used to show statistics about the ffserver operations.
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:
<Redirect NAME>
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
Metadata 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
Metadata author "Me"
Metadata copyright "Super MegaCorp"
Metadata title "Test stream from disk"
Metadata comment "Test comment"
</Stream>
ffserver-all(1), the doc/ffserver.conf example, ffmpeg(1), ffplay(1), ffprobe(1), ffmpeg-utils(1), ffmpeg-scaler(1), ffmpeg-resampler(1), ffmpeg-codecs(1), ffmpeg-bitstream-filters(1), ffmpeg-formats(1), ffmpeg-devices(1), ffmpeg-protocols(1), ffmpeg-filters(1)
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.