1 \input texinfo @c -*- texinfo -*-
3 @settitle ffserver Documentation
5 @center @titlefont{ffserver Documentation}
14 ffserver [@var{options}]
17 @c man begin DESCRIPTION
19 @command{ffserver} is a streaming server for both audio and video. It
20 supports several live feeds, streaming from files and time shifting on
21 live feeds (you can seek to positions in the past on each live feed,
22 provided you specify a big enough feed storage in
23 @file{ffserver.conf}).
25 @command{ffserver} receives prerecorded files or FFM streams from some
26 @command{ffmpeg} instance as input, then streams them over
29 An @command{ffserver} instance will listen on some port as specified
30 in the configuration file. You can launch one or more instances of
31 @command{ffmpeg} and send one or more FFM streams to the port where
32 ffserver is expecting to receive them. Alternately, you can make
33 @command{ffserver} launch such @command{ffmpeg} instances at startup.
35 Input streams are called feeds, and each one is specified by a
36 @code{<Feed>} section in the configuration file.
38 For each feed you can have different output streams in various
39 formats, each one specified by a @code{<Stream>} section in the
42 @section Status stream
44 ffserver supports an HTTP interface which exposes the current status
47 Simply point your browser to the address of the special status stream
48 specified in the configuration file.
50 For example if you have:
55 # Only allow local people to get the status
57 ACL allow 192.168.0.0 192.168.255.255
61 then the server will post a page with the status information when
62 the special stream @file{status.html} is requested.
64 @section What can this do?
66 When properly configured and running, you can capture video and audio in real
67 time from a suitable capture card, and stream it out over the Internet to
68 either Windows Media Player or RealAudio player (with some restrictions).
70 It can also stream from files, though that is currently broken. Very often, a
71 web server can be used to serve up the files just as well.
73 It can stream prerecorded video from .ffm files, though it is somewhat tricky
74 to make it work correctly.
76 @section How do I make it work?
78 First, build the kit. It *really* helps to have installed LAME first. Then when
79 you run the ffserver ./configure, make sure that you have the
80 @code{--enable-libmp3lame} flag turned on.
82 LAME is important as it allows for streaming audio to Windows Media Player.
83 Don't ask why the other audio types do not work.
85 As a simple test, just run the following two command lines where INPUTFILE
86 is some file which you can decode with ffmpeg:
89 ffserver -f doc/ffserver.conf &
90 ffmpeg -i INPUTFILE http://localhost:8090/feed1.ffm
93 At this point you should be able to go to your Windows machine and fire up
94 Windows Media Player (WMP). Go to Open URL and enter
97 http://<linuxbox>:8090/test.asf
100 You should (after a short delay) see video and hear audio.
102 WARNING: trying to stream test1.mpg doesn't work with WMP as it tries to
103 transfer the entire file before starting to play.
104 The same is true of AVI files.
106 @section What happens next?
108 You should edit the ffserver.conf file to suit your needs (in terms of
109 frame rates etc). Then install ffserver and ffmpeg, write a script to start
110 them up, and off you go.
112 @section Troubleshooting
114 @subsection I don't hear any audio, but video is fine.
116 Maybe you didn't install LAME, or got your ./configure statement wrong. Check
117 the ffmpeg output to see if a line referring to MP3 is present. If not, then
118 your configuration was incorrect. If it is, then maybe your wiring is not
119 set up correctly. Maybe the sound card is not getting data from the right
120 input source. Maybe you have a really awful audio interface (like I do)
121 that only captures in stereo and also requires that one channel be flipped.
122 If you are one of these people, then export 'AUDIO_FLIP_LEFT=1' before
125 @subsection The audio and video lose sync after a while.
129 @subsection After a long while, the video update rate goes way down in WMP.
131 Yes, it does. Who knows why?
133 @subsection WMP 6.4 behaves differently to WMP 7.
135 Yes, it does. Any thoughts on this would be gratefully received. These
136 differences extend to embedding WMP into a web page. [There are two
137 object IDs that you can use: The old one, which does not play well, and
138 the new one, which does (both tested on the same system). However,
139 I suspect that the new one is not available unless you have installed WMP 7].
141 @section What else can it do?
143 You can replay video from .ffm files that was recorded earlier.
144 However, there are a number of caveats, including the fact that the
145 ffserver parameters must match the original parameters used to record the
146 file. If they do not, then ffserver deletes the file before recording into it.
147 (Now that I write this, it seems broken).
149 You can fiddle with many of the codec choices and encoding parameters, and
150 there are a bunch more parameters that you cannot control. Post a message
151 to the mailing list if there are some 'must have' parameters. Look in
152 ffserver.conf for a list of the currently available controls.
154 It will automatically generate the ASX or RAM files that are often used
155 in browsers. These files are actually redirections to the underlying ASF
156 or RM file. The reason for this is that the browser often fetches the
157 entire file before starting up the external viewer. The redirection files
158 are very small and can be transferred quickly. [The stream itself is
159 often 'infinite' and thus the browser tries to download it and never
164 * When you connect to a live stream, most players (WMP, RA, etc) want to
165 buffer a certain number of seconds of material so that they can display the
166 signal continuously. However, ffserver (by default) starts sending data
167 in realtime. This means that there is a pause of a few seconds while the
168 buffering is being done by the player. The good news is that this can be
169 cured by adding a '?buffer=5' to the end of the URL. This means that the
170 stream should start 5 seconds in the past -- and so the first 5 seconds
171 of the stream are sent as fast as the network will allow. It will then
172 slow down to real time. This noticeably improves the startup experience.
174 You can also add a 'Preroll 15' statement into the ffserver.conf that will
175 add the 15 second prebuffering on all requests that do not otherwise
176 specify a time. In addition, ffserver will skip frames until a key_frame
177 is found. This further reduces the startup delay by not transferring data
178 that will be discarded.
180 * You may want to adjust the MaxBandwidth in the ffserver.conf to limit
181 the amount of bandwidth consumed by live streams.
183 @section Why does the ?buffer / Preroll stop working after a time?
185 It turns out that (on my machine at least) the number of frames successfully
186 grabbed is marginally less than the number that ought to be grabbed. This
187 means that the timestamp in the encoded data stream gets behind realtime.
188 This means that if you say 'Preroll 10', then when the stream gets 10
189 or more seconds behind, there is no Preroll left.
191 Fixing this requires a change in the internals of how timestamps are
194 @section Does the @code{?date=} stuff work.
196 Yes (subject to the limitation outlined above). Also note that whenever you
197 start ffserver, it deletes the ffm file (if any parameters have changed),
198 thus wiping out what you had recorded before.
200 The format of the @code{?date=xxxxxx} is fairly flexible. You should use one
201 of the following formats (the 'T' is literal):
204 * YYYY-MM-DDTHH:MM:SS (localtime)
205 * YYYY-MM-DDTHH:MM:SSZ (UTC)
208 You can omit the YYYY-MM-DD, and then it refers to the current day. However
209 note that @samp{?date=16:00:00} refers to 16:00 on the current day -- this
210 may be in the future and so is unlikely to be useful.
212 You use this by adding the ?date= to the end of the URL for the stream.
213 For example: @samp{http://localhost:8080/test.asf?date=2002-07-26T23:05:00}.
216 @section What is FFM, FFM2
218 FFM and FFM2 are formats used by ffserver. They allow storing a wide variety of
219 video and audio streams and encoding options, and can store a moving time segment
220 of an infinite movie or a whole movie.
222 FFM is version specific, and there is limited compatibility of FFM files
223 generated by one version of ffmpeg/ffserver and another version of
224 ffmpeg/ffserver. It may work but it is not guaranteed to work.
226 FFM2 is extensible while maintaining compatibility and should work between
227 differing versions of tools. FFM2 is the default.
232 @include avtools-common-opts.texi
234 @section Main options
237 @item -f @var{configfile}
238 Use @file{configfile} instead of @file{/etc/ffserver.conf}.
240 Enable no-launch mode. This option disables all the Launch directives
241 within the various <Stream> sections. Since ffserver will not launch
242 any ffmpeg instances, you will have to launch them manually.
244 Enable debug mode. This option increases log verbosity, directs log
254 @ifset config-avcodec
256 @include bitstream_filters.texi
258 @ifset config-avformat
259 @include formats.texi
260 @include protocols.texi
262 @ifset config-avdevice
263 @include devices.texi
265 @ifset config-swresample
266 @include resampler.texi
268 @ifset config-swscale
271 @ifset config-avfilter
272 @include filters.texi
280 @url{ffserver.html,ffserver},
282 @ifset config-not-all
283 @url{ffserver-all.html,ffserver-all},
285 the @file{doc/ffserver.conf} example,
286 @url{ffmpeg.html,ffmpeg}, @url{ffplay.html,ffplay}, @url{ffprobe.html,ffprobe},
287 @url{ffmpeg-utils.html,ffmpeg-utils},
288 @url{ffmpeg-scaler.html,ffmpeg-scaler},
289 @url{ffmpeg-resampler.html,ffmpeg-resampler},
290 @url{ffmpeg-codecs.html,ffmpeg-codecs},
291 @url{ffmpeg-bitstream-filters.html,ffmpeg-bitstream-filters},
292 @url{ffmpeg-formats.html,ffmpeg-formats},
293 @url{ffmpeg-devices.html,ffmpeg-devices},
294 @url{ffmpeg-protocols.html,ffmpeg-protocols},
295 @url{ffmpeg-filters.html,ffmpeg-filters}
302 @ifset config-not-all
305 the @file{doc/ffserver.conf} example, ffmpeg(1), ffplay(1), ffprobe(1),
306 ffmpeg-utils(1), ffmpeg-scaler(1), ffmpeg-resampler(1),
307 ffmpeg-codecs(1), ffmpeg-bitstream-filters(1), ffmpeg-formats(1),
308 ffmpeg-devices(1), ffmpeg-protocols(1), ffmpeg-filters(1)
311 @include authors.texi
315 @setfilename ffserver
316 @settitle ffserver video server