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6 <TITLE>FFserver Documentation</TITLE>
9 <H1>FFserver Documentation</H1>
12 <H1>Table of Contents</H1>
14 <LI><A NAME="TOC1" HREF="ffserver-doc.html#SEC1">1 Introduction</A>
15 <LI><A NAME="TOC2" HREF="ffserver-doc.html#SEC2">2 QuickStart</A>
17 <LI><A NAME="TOC3" HREF="ffserver-doc.html#SEC3">2.1 What can this do?</A>
18 <LI><A NAME="TOC4" HREF="ffserver-doc.html#SEC4">2.2 What do I need?</A>
19 <LI><A NAME="TOC5" HREF="ffserver-doc.html#SEC5">2.3 How do I make it work?</A>
20 <LI><A NAME="TOC6" HREF="ffserver-doc.html#SEC6">2.4 What happens next?</A>
21 <LI><A NAME="TOC7" HREF="ffserver-doc.html#SEC7">2.5 Troubleshooting</A>
23 <LI><A NAME="TOC8" HREF="ffserver-doc.html#SEC8">2.5.1 I don't hear any audio, but video is fine</A>
24 <LI><A NAME="TOC9" HREF="ffserver-doc.html#SEC9">2.5.2 The audio and video loose sync after a while.</A>
25 <LI><A NAME="TOC10" HREF="ffserver-doc.html#SEC10">2.5.3 After a long while, the video update rate goes way down in WMP.</A>
26 <LI><A NAME="TOC11" HREF="ffserver-doc.html#SEC11">2.5.4 WMP 6.4 behaves differently to WMP 7.</A>
28 <LI><A NAME="TOC12" HREF="ffserver-doc.html#SEC12">2.6 What else can it do?</A>
29 <LI><A NAME="TOC13" HREF="ffserver-doc.html#SEC13">2.7 Tips</A>
30 <LI><A NAME="TOC14" HREF="ffserver-doc.html#SEC14">2.8 Why does the ?buffer / Preroll stop working after a time?</A>
31 <LI><A NAME="TOC15" HREF="ffserver-doc.html#SEC15">2.9 Does the <CODE>?date=</CODE> stuff work.</A>
37 FFserver Documentation
44 <H1><A NAME="SEC1" HREF="ffserver-doc.html#TOC1">1 Introduction</A></H1>
47 FFserver is a streaming server for both audio and video. It supports
48 several live feeds, streaming from files and time shifting on live feeds
49 (you can seek to positions in the past on each live feed, provided you
50 specify a big enough feed storage in ffserver.conf).
54 This documentation covers only the streaming aspects of ffserver /
55 ffmpeg. All questions about parameters for ffmpeg, codec questions,
56 etc. are not covered here. Read <TT>`ffmpeg-doc.[texi|html]'</TT> for more
62 <H1><A NAME="SEC2" HREF="ffserver-doc.html#TOC2">2 QuickStart</A></H1>
65 [Contributed by Philip Gladstone, philip-ffserver at gladstonefamily dot net]
70 <H2><A NAME="SEC3" HREF="ffserver-doc.html#TOC3">2.1 What can this do?</A></H2>
73 When properly configured and running, you can capture video and audio in real
74 time from a suitable capture card, and stream it out over the Internet to
75 either Windows Media Player or RealAudio player (with some restrictions).
79 It can also stream from files, though that is currently broken. Very often, a
80 web server can be used to serve up the files just as well.
84 It can stream prerecorded video from .ffm files, though it is somewhat tricky
85 to make it work correctly.
90 <H2><A NAME="SEC4" HREF="ffserver-doc.html#TOC4">2.2 What do I need?</A></H2>
93 I use Linux on a 900MHz Duron with a cheapo Bt848 based TV capture card. I'm
94 using stock linux 2.4.17 with the stock drivers. [Actually that isn't true,
95 I needed some special drivers from my motherboard based sound card.]
99 I understand that FreeBSD systems work just fine as well.
104 <H2><A NAME="SEC5" HREF="ffserver-doc.html#TOC5">2.3 How do I make it work?</A></H2>
107 First, build the kit. It *really* helps to have installed LAME first. Then when
108 you run the ffserver ./configure, make sure that you have the --enable-mp3lame
113 LAME is important as it allows streaming of audio to Windows Media Player. Don't
114 ask why the other audio types do not work.
118 As a simple test, just run the following two command lines (assuming that you
119 have a V4L video capture card):
124 ./ffserver -f doc/ffserver.conf &
125 ./ffmpeg http://localhost:8090/feed1.ffm
129 At this point you should be able to go to your windows machine and fire up
130 Windows Media Player (WMP). Go to Open URL and enter
135 http://<linuxbox>:8090/test.asf
139 You should see (after a short delay) video and hear audio.
143 WARNING: trying to stream test1.mpg doesn't work with WMP as it tries to
144 transfer the entire file before starting to play. The same is true of avi files.
149 <H2><A NAME="SEC6" HREF="ffserver-doc.html#TOC6">2.4 What happens next?</A></H2>
152 You should edit the ffserver.conf file to suit your needs (in terms of
153 frame rates etc). Then install ffserver and ffmpeg, write a script to start
154 them up, and off you go.
159 <H2><A NAME="SEC7" HREF="ffserver-doc.html#TOC7">2.5 Troubleshooting</A></H2>
163 <H3><A NAME="SEC8" HREF="ffserver-doc.html#TOC8">2.5.1 I don't hear any audio, but video is fine</A></H3>
166 Maybe you didn't install LAME, or get your ./configure statement right. Check
167 the ffmpeg output to see if a line referring to mp3 is present. If not, then
168 your configuration was incorrect. If it is, then maybe your wiring is not
169 setup correctly. Maybe the sound card is not getting data from the right
170 input source. Maybe you have a really awful audio interface (like I do)
171 that only captures in stereo and also requires that one channel be flipped.
172 If you are one of these people, then export 'AUDIO_FLIP_LEFT=1' before
178 <H3><A NAME="SEC9" HREF="ffserver-doc.html#TOC9">2.5.2 The audio and video loose sync after a while.</A></H3>
186 <H3><A NAME="SEC10" HREF="ffserver-doc.html#TOC10">2.5.3 After a long while, the video update rate goes way down in WMP.</A></H3>
189 Yes, it does. Who knows why?
194 <H3><A NAME="SEC11" HREF="ffserver-doc.html#TOC11">2.5.4 WMP 6.4 behaves differently to WMP 7.</A></H3>
197 Yes, it does. Any thoughts on this would be gratefully received. These
198 differences extend to embedding WMP into a web page. [There are two
199 different object ids that you can use, one of them -- the old one -- cannot
200 play very well, and the new one works well (both on the same system). However,
201 I suspect that the new one is not available unless you have installed WMP 7].
206 <H2><A NAME="SEC12" HREF="ffserver-doc.html#TOC12">2.6 What else can it do?</A></H2>
209 You can replay video from .ffm files that was recorded earlier.
210 However, there are a number of caveats which include the fact that the
211 ffserver parameters must match the original parameters used to record the
212 file. If not, then ffserver deletes the file before recording into it. (Now I write
213 this, this seems broken).
217 You can fiddle with many of the codec choices and encoding parameters, and
218 there are a bunch more parameters that you cannot control. Post a message
219 to the mailing list if there are some 'must have' parameters. Look in the
220 ffserver.conf for a list of the currently available controls.
224 It will automatically generate the .ASX or .RAM files that are often used
225 in browsers. These files are actually redirections to the underlying .ASF
226 or .RM file. The reason for this is that the browser often fetches the
227 entire file before starting up the external viewer. The redirection files
228 are very small and can be transferred quickly. [The stream itself is
229 often 'infinite' and thus the browser tries to download it and never
235 <H2><A NAME="SEC13" HREF="ffserver-doc.html#TOC13">2.7 Tips</A></H2>
238 * When you connect to a live stream, most players (WMP, RA etc) want to
239 buffer a certain number of seconds of material so that they can display the
240 signal continuously. However, ffserver (by default) starts sending data
241 in real time. This means that there is a pause of a few seconds while the
242 buffering is being done by the player. The good news is that this can be
243 cured by adding a '?buffer=5' to the end of the URL. This says that the
244 stream should start 5 seconds in the past -- and so the first 5 seconds
245 of the stream is sent as fast as the network will allow. It will then
246 slow down to real time. This noticeably improves the startup experience.
250 You can also add a 'Preroll 15' statement into the ffserver.conf that will
251 add the 15 second prebuffering on all requests that do not otherwise
252 specify a time. In addition, ffserver will skip frames until a key_frame
253 is found. This further reduces the startup delay by not transferring data
254 that will be discarded.
258 * You may want to adjust the MaxBandwidth in the ffserver.conf to limit
259 the amount of bandwidth consumed by live streams.
264 <H2><A NAME="SEC14" HREF="ffserver-doc.html#TOC14">2.8 Why does the ?buffer / Preroll stop working after a time?</A></H2>
267 It turns out that (on my machine at least) the number of frames successfully
268 grabbed is marginally less than the number that ought to be grabbed. This
269 means that the timestamp in the encoded data stream gets behind real time.
270 This means that if you say 'preroll 10', then when the stream gets 10
271 or more seconds behind, there is no preroll left.
275 Fixing this requires a change in the internals in how timestamps are
281 <H2><A NAME="SEC15" HREF="ffserver-doc.html#TOC15">2.9 Does the <CODE>?date=</CODE> stuff work.</A></H2>
284 Yes (subject to the caution above). Also note that whenever you start
285 ffserver, it deletes the ffm file (if any parameters hacve changed), thus wiping out what you had recorded
290 The format of the <CODE>?date=xxxxxx</CODE> is fairly flexible. You should use one
291 of the following formats (the 'T' is literal):
296 * YYYY-MM-DDTHH:MM:SS (localtime)
297 * YYYY-MM-DDTHH:MM:SSZ (UTC)
301 You can omit the YYYY-MM-DD, and then it refers to the current day. However
302 note that <SAMP>`?date=16:00:00'</SAMP> refers to 4PM on the current day -- this may be
303 in the future and so unlikely to useful.
307 You use this by adding the ?date= to the end of the URL for the stream.
308 For example: <SAMP>`http://localhost:8080/test.asf?date=2002-07-26T23:05:00'</SAMP>.
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