Synopsis
********

ffserver [OPTIONS]

Description
***********

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.

Detailed description
********************

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, FFM2 formats
=================

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.

Status stream
=============

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.

How do I make it work?
======================

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.

What else can it do?
====================

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.]

Tips
====

* 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.

Why does the ?buffer / Preroll stop working after a time?
=========================================================

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.

Does the ?date= stuff work.
===========================

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.

Options
*******

     [file fftools-common-opts.texi not included]

Main options
============

-f CONFIGFILE
     Read configuration file configfile. If not specified it will read by default from /etc/ffserver.conf.

-n
     Enable no-launch mode. This option disables all the Launch directives within the various <Feed> sections. Since ffserver will not launch any ffmpeg instances, you will have to launch them manually.

-d
     Enable debug mode. This option increases log verbosity, and directs log messages to stdout. When specified, the CustomLog option is ignored.

Configuration file syntax
*************************

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.

ACL syntax
==========

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

  * Allow/deny access to ADDRESS.

          ACL ALLOW <address>
          ACL DENY <address>

  * Allow/deny access to ranges of addresses from FIRST_ADDRESS to LAST_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.

Global options
==============

HTTPPort PORT_NUMBER

Port PORT_NUMBER

RTSPPort PORT_NUMBER

     HTTPPORT sets the HTTP server listening TCP port number, RTSPPORT sets the RTSP server listening TCP port number.

     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.

HTTPBindAddress IP_ADDRESS

BindAddress IP_ADDRESS

RTSPBindAddress IP_ADDRESS
     Set address on which the HTTP/RTSP server is bound. Only useful if you have several network interfaces.

     BINDADDRESS is the equivalent of HTTPBINDADDRESS and is deprecated.

MaxHTTPConnections N
     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.

MaxClients N
     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.

MaxBandwidth KBPS
     Set the maximum amount of kbit/sec that you are prepared to consume when streaming to clients.

     Default value is 1000.

CustomLog FILENAME
     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.

NoDaemon
     Set no-daemon mode. This option is currently ignored since now ffserver will always work in no-daemon mode, and is deprecated.

UseDefaults

NoDefaults
     Control whether default codec options are used for the all streams or not. Each stream may overwrite this setting for its own. Default is USEDEFAULTS. The lastest occurrence overrides previous if multiple definitions.

Feed section
============

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.

File FILENAME

ReadOnlyFile FILENAME
     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
     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).

FileMaxSize SIZE
     Set maximum size of the feed file in bytes. 0 means unlimited. The postfixes K (2^10), M (2^20), and G (2^30) are recognized.

     Default value is 5M.

Launch ARGS
     Launch an ffmpeg command when creating ffserver.

     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.

ACL SPEC
     Specify the list of IP address which are allowed or denied to write the feed. Multiple ACL options can be specified.

Stream section
==============

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.

Feed FEED_NAME
     Set the input feed. FEED_NAME must correspond to an existing feed defined in a Feed section.

     When this option is set, encoding options are used to setup the encoding operated by the remote ffmpeg process.

File FILENAME
     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.

Format FORMAT_NAME
     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.

InputFormat FORMAT_NAME
     Set input format. If not specified, it is automatically guessed.

Preroll N
     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.

StartSendOnKey
     Do not send stream until it gets the first key frame. By default ffserver will send data immediately.

MaxTime N
     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.

ACL SPEC
     Set ACL for the stream.

DynamicACL SPEC

RTSPOption OPTION

MulticastAddress ADDRESS

MulticastPort PORT

MulticastTTL INTEGER

NoLoop

FaviconURL URL
     Set favicon (favourite icon) for the server status page. It is ignored for regular streams.

Author VALUE

Comment VALUE

Copyright VALUE

Title VALUE
     Set metadata corresponding to the option. All these options are deprecated in favor of Metadata.

Metadata KEY VALUE
     Set metadata value on the output stream.

UseDefaults

NoDefaults
     Control whether default codec options are used for the stream or not. Default is USEDEFAULTS unless disabled globally.

NoAudio

NoVideo
     Suppress audio/video.

AudioCodec CODEC_NAME (encoding,audio)
     Set audio codec.

AudioBitRate RATE (encoding,audio)
     Set bitrate for the audio stream in kbits per second.

AudioChannels N (encoding,audio)
     Set number of audio channels.

AudioSampleRate N (encoding,audio)
     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.

AVOptionAudio [CODEC:]OPTION VALUE (encoding,audio)
     Set generic or private option for audio stream. Private option must be prefixed with codec name or codec must be defined before.

AVPresetAudio PRESET (encoding,audio)
     Set preset for audio stream.

VideoCodec CODEC_NAME (encoding,video)
     Set video codec.

VideoBitRate N (encoding,video)
     Set bitrate for the video stream in kbits per second.

VideoBitRateRange RANGE (encoding,video)
     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.

VideoBitRateRangeTolerance N (encoding,video)
     Set video bitrate tolerance in kbits per second.

PixelFormat PIXEL_FORMAT (encoding,video)
     Set video pixel format.

Debug INTEGER (encoding,video)
     Set video debug encoding option.

Strict INTEGER (encoding,video)
     Set video strict encoding option.

VideoBufferSize N (encoding,video)
     Set ratecontrol buffer size, expressed in KB.

VideoFrameRate N (encoding,video)
     Set number of video frames per second.

VideoSize (encoding,video)
     Set size of the video frame, must be an abbreviation or in the form WxH.  See the Video size section in the ffmpeg-utils(1) manual (ffmpeg-utils).

     Default value is 160x128.

VideoIntraOnly (encoding,video)
     Transmit only intra frames (useful for low bitrates, but kills frame rate).

VideoGopSize N (encoding,video)
     If non-intra only, an intra frame is transmitted every VideoGopSize frames. Video synchronization can only begin at an intra frame.

VideoTag TAG (encoding,video)
     Set video tag.

VideoHighQuality (encoding,video)

Video4MotionVector (encoding,video)

BitExact (encoding,video)
     Set bitexact encoding flag.

IdctSimple (encoding,video)
     Set simple IDCT algorithm.

Qscale N (encoding,video)
     Enable constant quality encoding, and set video qscale (quantization scale) value, expressed in N QP units.

VideoQMin N (encoding,video)

VideoQMax N (encoding,video)
     Set video qmin/qmax.

VideoQDiff INTEGER (encoding,video)
     Set video qdiff encoding option.

LumiMask FLOAT (encoding,video)

DarkMask FLOAT (encoding,video)
     Set lumi_mask/dark_mask encoding options.

AVOptionVideo [CODEC:]OPTION VALUE (encoding,video)
     Set generic or private option for video stream. Private option must be prefixed with codec name or codec must be defined before.

AVPresetVideo PRESET (encoding,video)
     Set preset for video stream.

     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.

Redirect section
================

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 examples
***************

  * Multipart JPEG

          <Stream test.mjpg>
          Feed feed1.ffm
          Format mpjpeg
          VideoFrameRate 2
          VideoIntraOnly
          NoAudio
          Strict -1
          </Stream>

  * Single JPEG

          <Stream test.jpg>
          Feed feed1.ffm
          Format jpeg
          VideoFrameRate 2
          VideoIntraOnly
          VideoSize 352x240
          NoAudio
          Strict -1
          </Stream>

  * Flash

          <Stream test.swf>
          Feed feed1.ffm
          Format swf
          VideoFrameRate 2
          VideoIntraOnly
          NoAudio
          </Stream>

  * ASF compatible

          <Stream test.asf>
          Feed feed1.ffm
          Format asf
          VideoFrameRate 15
          VideoSize 352x240
          VideoBitRate 256
          VideoBufferSize 40
          VideoGopSize 30
          AudioBitRate 64
          StartSendOnKey
          </Stream>

  * MP3 audio

          <Stream test.mp3>
          Feed feed1.ffm
          Format mp2
          AudioCodec mp3
          AudioBitRate 64
          AudioChannels 1
          AudioSampleRate 44100
          NoVideo
          </Stream>

  * Ogg Vorbis audio

          <Stream test.ogg>
          Feed feed1.ffm
          Metadata title "Stream title"
          AudioBitRate 64
          AudioChannels 2
          AudioSampleRate 44100
          NoVideo
          </Stream>

  * Real with audio only at 32 kbits

          <Stream test.ra>
          Feed feed1.ffm
          Format rm
          AudioBitRate 32
          NoVideo
          </Stream>

  * Real with audio and video at 64 kbits

          <Stream test.rm>
          Feed feed1.ffm
          Format rm
          AudioBitRate 32
          VideoBitRate 128
          VideoFrameRate 25
          VideoGopSize 25
          </Stream>

  * For stream coming from a file: you only need to set the input filename and optionally a new format.

          <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>

     [file config.texi not included]

See Also
********

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)

     [file authors.texi not included]