List the FFserver specific options under a "Main options" section, to
[libav.git] / doc / ffserver-doc.texi
1 \input texinfo @c -*- texinfo -*-
3 @settitle FFserver Documentation
4 @titlepage
5 @sp 7
6 @center @titlefont{FFserver Documentation}
7 @sp 3
8 @end titlepage
11 @chapter Introduction
13 @c man begin DESCRIPTION
14 FFserver is a streaming server for both audio and video. It supports
15 several live feeds, streaming from files and time shifting on live feeds
16 (you can seek to positions in the past on each live feed, provided you
17 specify a big enough feed storage in ffserver.conf).
19 FFserver runs in daemon mode by default; that is, it puts itself in
20 the background and detaches from its TTY, unless it is launched in
21 debug mode or a NoDaemon option is specified in the configuration
22 file.
24 This documentation covers only the streaming aspects of ffserver /
25 ffmpeg. All questions about parameters for ffmpeg, codec questions,
26 etc. are not covered here. Read @file{ffmpeg-doc.html} for more
27 information.
29 @section How does it work?
31 FFserver receives prerecorded files or FFM streams from some ffmpeg
32 instance as input, then streams them over RTP/RTSP/HTTP.
34 An ffserver instance will listen on some port as specified in the
35 configuration file. You can launch one or more instances of ffmpeg and
36 send one or more FFM streams to the port where ffserver is expecting
37 to receive them. Alternately, you can make ffserver launch such ffmpeg
38 instances at startup.
40 Input streams are called feeds, and each one is specified by a <Feed>
41 section in the configuration file.
43 For each feed you can have different output streams in various
44 formats, each one specified by a <Stream> section in the configuration
45 file.
47 @section Status stream
49 FFserver supports an HTTP interface which exposes the current status
50 of the server.
52 Simply point your browser to the address of the special status stream
53 specified in the configuration file.
55 For example if you have:
56 @example
57 <Stream status.html>
58 Format status
60 # Only allow local people to get the status
61 ACL allow localhost
62 ACL allow
63 </Stream>
64 @end example
66 then the server will post a page with the status information when
67 the special stream @file{status.html} is requested.
69 @section What can this do?
71 When properly configured and running, you can capture video and audio in real
72 time from a suitable capture card, and stream it out over the Internet to
73 either Windows Media Player or RealAudio player (with some restrictions).
75 It can also stream from files, though that is currently broken. Very often, a
76 web server can be used to serve up the files just as well.
78 It can stream prerecorded video from .ffm files, though it is somewhat tricky
79 to make it work correctly.
81 @section What do I need?
83 I use Linux on a 900 MHz Duron with a cheapo Bt848 based TV capture card. I'm
84 using stock Linux 2.4.17 with the stock drivers. [Actually that isn't true,
85 I needed some special drivers for my motherboard-based sound card.]
87 I understand that FreeBSD systems work just fine as well.
89 @section How do I make it work?
91 First, build the kit. It *really* helps to have installed LAME first. Then when
92 you run the ffserver ./configure, make sure that you have the
93 @code{--enable-libmp3lame} flag turned on.
95 LAME is important as it allows for streaming audio to Windows Media Player.
96 Don't ask why the other audio types do not work.
98 As a simple test, just run the following two command lines where INPUTFILE
99 is some file which you can decode with ffmpeg:
101 @example
102 ./ffserver -f doc/ffserver.conf &
103 ./ffmpeg -i INPUTFILE http://localhost:8090/feed1.ffm
104 @end example
106 At this point you should be able to go to your Windows machine and fire up
107 Windows Media Player (WMP). Go to Open URL and enter
109 @example
110 http://<linuxbox>:8090/test.asf
111 @end example
113 You should (after a short delay) see video and hear audio.
115 WARNING: trying to stream test1.mpg doesn't work with WMP as it tries to
116 transfer the entire file before starting to play.
117 The same is true of AVI files.
119 @section What happens next?
121 You should edit the ffserver.conf file to suit your needs (in terms of
122 frame rates etc). Then install ffserver and ffmpeg, write a script to start
123 them up, and off you go.
125 @section Troubleshooting
127 @subsection I don't hear any audio, but video is fine.
129 Maybe you didn't install LAME, or got your ./configure statement wrong. Check
130 the ffmpeg output to see if a line referring to MP3 is present. If not, then
131 your configuration was incorrect. If it is, then maybe your wiring is not
132 set up correctly. Maybe the sound card is not getting data from the right
133 input source. Maybe you have a really awful audio interface (like I do)
134 that only captures in stereo and also requires that one channel be flipped.
135 If you are one of these people, then export 'AUDIO_FLIP_LEFT=1' before
136 starting ffmpeg.
138 @subsection The audio and video loose sync after a while.
140 Yes, they do.
142 @subsection After a long while, the video update rate goes way down in WMP.
144 Yes, it does. Who knows why?
146 @subsection WMP 6.4 behaves differently to WMP 7.
148 Yes, it does. Any thoughts on this would be gratefully received. These
149 differences extend to embedding WMP into a web page. [There are two
150 object IDs that you can use: The old one, which does not play well, and
151 the new one, which does (both tested on the same system). However,
152 I suspect that the new one is not available unless you have installed WMP 7].
154 @section What else can it do?
156 You can replay video from .ffm files that was recorded earlier.
157 However, there are a number of caveats, including the fact that the
158 ffserver parameters must match the original parameters used to record the
159 file. If they do not, then ffserver deletes the file before recording into it.
160 (Now that I write this, it seems broken).
162 You can fiddle with many of the codec choices and encoding parameters, and
163 there are a bunch more parameters that you cannot control. Post a message
164 to the mailing list if there are some 'must have' parameters. Look in
165 ffserver.conf for a list of the currently available controls.
167 It will automatically generate the ASX or RAM files that are often used
168 in browsers. These files are actually redirections to the underlying ASF
169 or RM file. The reason for this is that the browser often fetches the
170 entire file before starting up the external viewer. The redirection files
171 are very small and can be transferred quickly. [The stream itself is
172 often 'infinite' and thus the browser tries to download it and never
173 finishes.]
175 @section Tips
177 * When you connect to a live stream, most players (WMP, RA, etc) want to
178 buffer a certain number of seconds of material so that they can display the
179 signal continuously. However, ffserver (by default) starts sending data
180 in realtime. This means that there is a pause of a few seconds while the
181 buffering is being done by the player. The good news is that this can be
182 cured by adding a '?buffer=5' to the end of the URL. This means that the
183 stream should start 5 seconds in the past -- and so the first 5 seconds
184 of the stream are sent as fast as the network will allow. It will then
185 slow down to real time. This noticeably improves the startup experience.
187 You can also add a 'Preroll 15' statement into the ffserver.conf that will
188 add the 15 second prebuffering on all requests that do not otherwise
189 specify a time. In addition, ffserver will skip frames until a key_frame
190 is found. This further reduces the startup delay by not transferring data
191 that will be discarded.
193 * You may want to adjust the MaxBandwidth in the ffserver.conf to limit
194 the amount of bandwidth consumed by live streams.
196 @section Why does the ?buffer / Preroll stop working after a time?
198 It turns out that (on my machine at least) the number of frames successfully
199 grabbed is marginally less than the number that ought to be grabbed. This
200 means that the timestamp in the encoded data stream gets behind realtime.
201 This means that if you say 'Preroll 10', then when the stream gets 10
202 or more seconds behind, there is no Preroll left.
204 Fixing this requires a change in the internals of how timestamps are
205 handled.
207 @section Does the @code{?date=} stuff work.
209 Yes (subject to the limitation outlined above). Also note that whenever you
210 start ffserver, it deletes the ffm file (if any parameters have changed),
211 thus wiping out what you had recorded before.
213 The format of the @code{?date=xxxxxx} is fairly flexible. You should use one
214 of the following formats (the 'T' is literal):
216 @example
217 * YYYY-MM-DDTHH:MM:SS (localtime)
219 @end example
221 You can omit the YYYY-MM-DD, and then it refers to the current day. However
222 note that @samp{?date=16:00:00} refers to 16:00 on the current day -- this
223 may be in the future and so is unlikely to be useful.
225 You use this by adding the ?date= to the end of the URL for the stream.
226 For example: @samp{http://localhost:8080/test.asf?date=2002-07-26T23:05:00}.
227 @c man end
229 @chapter Invocation
230 @section Syntax
231 @example
232 @c man begin SYNOPSIS
233 ffserver [options]
234 @c man end
235 @end example
237 @section Options
238 @c man begin OPTIONS
240 @include fftools-common-opts.texi
242 @section Main options
244 @table @option
245 @item -f @var{configfile}
246 Use @file{configfile} instead of @file{/etc/ffserver.conf}.
247 @item -n
248 Enable no-launch mode. This option disables all the Launch directives
249 within the various <Stream> sections. FFserver will not launch any
250 ffmpeg instance, so you will have to launch them manually.
251 @item -d
252 Enable debug mode. This option increases log verbosity, directs log
253 messages to stdout and causes ffserver to run in the foreground
254 rather than as a daemon.
255 @end table
256 @c man end
258 @ignore
260 @setfilename ffserver
261 @settitle FFserver video server
263 @c man begin SEEALSO
264 ffmpeg(1), ffplay(1), the @file{ffmpeg/doc/ffserver.conf} example and
265 the HTML documentation of @file{ffmpeg}.
266 @c man end
268 @c man begin AUTHOR
269 Fabrice Bellard
270 @c man end
272 @end ignore
274 @bye