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3 <!-- Created by texi2html 1.56k from ffserver-doc.texi on 28 December 2002 -->
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5 <TITLE>FFserver Documentation</TITLE>
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7 <BODY>
8 <H1>FFserver Documentation</H1>
9 <P>
10 <P><HR><P>
11 <H1>Table of Contents</H1>
12 <UL>
13 <LI><A NAME="TOC1" HREF="ffserver-doc.html#SEC1">1. Introduction</A>
14 <LI><A NAME="TOC2" HREF="ffserver-doc.html#SEC2">2. QuickStart</A>
15 <UL>
16 <LI><A NAME="TOC3" HREF="ffserver-doc.html#SEC3">2.1 What can this do?</A>
17 <LI><A NAME="TOC4" HREF="ffserver-doc.html#SEC4">2.2 What do I need?</A>
18 <LI><A NAME="TOC5" HREF="ffserver-doc.html#SEC5">2.3 How do I make it work?</A>
19 <LI><A NAME="TOC6" HREF="ffserver-doc.html#SEC6">2.4 What happens next?</A>
20 <LI><A NAME="TOC7" HREF="ffserver-doc.html#SEC7">2.5 Troubleshooting</A>
21 <UL>
22 <LI><A NAME="TOC8" HREF="ffserver-doc.html#SEC8">2.5.1 I don't hear any audio, but video is fine</A>
23 <LI><A NAME="TOC9" HREF="ffserver-doc.html#SEC9">2.5.2 The audio and video loose sync after a while.</A>
24 <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>
25 <LI><A NAME="TOC11" HREF="ffserver-doc.html#SEC11">2.5.4 WMP 6.4 behaves differently to WMP 7.</A>
26 </UL>
27 <LI><A NAME="TOC12" HREF="ffserver-doc.html#SEC12">2.6 What else can it do?</A>
28 <LI><A NAME="TOC13" HREF="ffserver-doc.html#SEC13">2.7 Tips</A>
29 <LI><A NAME="TOC14" HREF="ffserver-doc.html#SEC14">2.8 Why does the ?buffer / Preroll stop working after a time?</A>
30 <LI><A NAME="TOC15" HREF="ffserver-doc.html#SEC15">2.9 Does the <CODE>?date=</CODE> stuff work.</A>
31 </UL>
32 </UL>
33 <P><HR><P>
34
35 <P>
36 FFserver Documentation
37
38
39
40
41 <H1><A NAME="SEC1" HREF="ffserver-doc.html#TOC1">1. Introduction</A></H1>
42
43 <P>
44 FFserver is a streaming server for both audio and video. It supports
45 several live feeds, streaming from files and time shifting on live feeds
46 (you can seek to positions in the past on each live feed, provided you
47 specify a big enough feed storage in ffserver.conf).
48
49
50 <P>
51 This documentation covers only the streaming aspects of ffserver /
52 ffmpeg. All questions about parameters for ffmpeg, codec questions,
53 etc. are not covered here. Read <TT>`ffmpeg-doc.[texi|html]'</TT> for more
54 information.
55
56
57
58
59 <H1><A NAME="SEC2" HREF="ffserver-doc.html#TOC2">2. QuickStart</A></H1>
60
61 <P>
62 [Contributed by Philip Gladstone, philip-ffserver at gladstonefamily dot net]
63
64
65
66
67 <H2><A NAME="SEC3" HREF="ffserver-doc.html#TOC3">2.1 What can this do?</A></H2>
68
69 <P>
70 When properly configured and running, you can capture video and audio in real
71 time from a suitable capture card, and stream it out over the Internet to
72 either Windows Media Player or RealAudio player (with some restrictions).
73
74
75 <P>
76 It can also stream from files, though that is currently broken. Very often, a
77 web server can be used to serve up the files just as well.
78
79
80 <P>
81 It can stream prerecorded video from .ffm files, though it is somewhat tricky
82 to make it work correctly.
83
84
85
86
87 <H2><A NAME="SEC4" HREF="ffserver-doc.html#TOC4">2.2 What do I need?</A></H2>
88
89 <P>
90 I use Linux on a 900MHz Duron with a cheapo Bt848 based TV capture card. I'm
91 using stock linux 2.4.17 with the stock drivers. [Actually that isn't true,
92 I needed some special drivers from my motherboard based sound card.]
93
94
95 <P>
96 I understand that FreeBSD systems work just fine as well.
97
98
99
100
101 <H2><A NAME="SEC5" HREF="ffserver-doc.html#TOC5">2.3 How do I make it work?</A></H2>
102
103 <P>
104 First, build the kit. It *really* helps to have installed LAME first. Then when
105 you run the ffserver ./configure, make sure that you have the --enable-mp3lame
106 flag turned on.
107
108
109 <P>
110 LAME is important as it allows streaming of audio to Windows Media Player. Don't
111 ask why the other audio types do not work.
112
113
114 <P>
115 As a simple test, just run the following two command lines (assuming that you
116 have a V4L video capture card):
117
118
119
120 <PRE>
121 ./ffserver -f doc/ffserver.conf &#38;
122 ./ffmpeg http://localhost:8090/feed1.ffm
123 </PRE>
124
125 <P>
126 At this point you should be able to go to your windows machine and fire up
127 Windows Media Player (WMP). Go to Open URL and enter
128
129
130
131 <PRE>
132 http://&#60;linuxbox&#62;:8090/test.asf
133 </PRE>
134
135 <P>
136 You should see (after a short delay) video and hear audio.
137
138
139 <P>
140 WARNING: trying to stream test1.mpg doesn't work with WMP as it tries to
141 transfer the entire file before starting to play. The same is true of avi files.
142
143
144
145
146 <H2><A NAME="SEC6" HREF="ffserver-doc.html#TOC6">2.4 What happens next?</A></H2>
147
148 <P>
149 You should edit the ffserver.conf file to suit your needs (in terms of
150 frame rates etc). Then install ffserver and ffmpeg, write a script to start
151 them up, and off you go.
152
153
154
155
156 <H2><A NAME="SEC7" HREF="ffserver-doc.html#TOC7">2.5 Troubleshooting</A></H2>
157
158
159
160 <H3><A NAME="SEC8" HREF="ffserver-doc.html#TOC8">2.5.1 I don't hear any audio, but video is fine</A></H3>
161
162 <P>
163 Maybe you didn't install LAME, or get your ./configure statement right. Check
164 the ffmpeg output to see if a line referring to mp3 is present. If not, then
165 your configuration was incorrect. If it is, then maybe your wiring is not
166 setup correctly. Maybe the sound card is not getting data from the right
167 input source. Maybe you have a really awful audio interface (like I do)
168 that only captures in stereo and also requires that one channel be flipped.
169 If you are one of these people, then export 'AUDIO_FLIP_LEFT=1' before
170 starting ffmpeg.
171
172
173
174
175 <H3><A NAME="SEC9" HREF="ffserver-doc.html#TOC9">2.5.2 The audio and video loose sync after a while.</A></H3>
176
177 <P>
178 Yes, they do.
179
180
181
182
183 <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>
184
185 <P>
186 Yes, it does. Who knows why?
187
188
189
190
191 <H3><A NAME="SEC11" HREF="ffserver-doc.html#TOC11">2.5.4 WMP 6.4 behaves differently to WMP 7.</A></H3>
192
193 <P>
194 Yes, it does. Any thoughts on this would be gratefully received. These
195 differences extend to embedding WMP into a web page. [There are two
196 different object ids that you can use, one of them -- the old one -- cannot
197 play very well, and the new one works well (both on the same system). However,
198 I suspect that the new one is not available unless you have installed WMP 7].
199
200
201
202
203 <H2><A NAME="SEC12" HREF="ffserver-doc.html#TOC12">2.6 What else can it do?</A></H2>
204
205 <P>
206 You can replay video from .ffm files that was recorded earlier.
207 However, there are a number of caveats which include the fact that the
208 ffserver parameters must match the original parameters used to record the
209 file. If not, then ffserver deletes the file before recording into it. (Now I write
210 this, this seems broken).
211
212
213 <P>
214 You can fiddle with many of the codec choices and encoding parameters, and
215 there are a bunch more parameters that you cannot control. Post a message
216 to the mailing list if there are some 'must have' parameters. Look in the
217 ffserver.conf for a list of the currently available controls.
218
219
220 <P>
221 It will automatically generate the .ASX or .RAM files that are often used
222 in browsers. These files are actually redirections to the underlying .ASF
223 or .RM file. The reason for this is that the browser often fetches the
224 entire file before starting up the external viewer. The redirection files
225 are very small and can be transferred quickly. [The stream itself is
226 often 'infinite' and thus the browser tries to download it and never
227 finishes.]
228
229
230
231
232 <H2><A NAME="SEC13" HREF="ffserver-doc.html#TOC13">2.7 Tips</A></H2>
233
234 <P>
235 * When you connect to a live stream, most players (WMP, RA etc) want to
236 buffer a certain number of seconds of material so that they can display the
237 signal continuously. However, ffserver (by default) starts sending data
238 in real time. This means that there is a pause of a few seconds while the
239 buffering is being done by the player. The good news is that this can be
240 cured by adding a '?buffer=5' to the end of the URL. This says that the
241 stream should start 5 seconds in the past -- and so the first 5 seconds
242 of the stream is sent as fast as the network will allow. It will then
243 slow down to real time. This noticeably improves the startup experience.
244
245
246 <P>
247 You can also add a 'Preroll 15' statement into the ffserver.conf that will
248 add the 15 second prebuffering on all requests that do not otherwise
249 specify a time. In addition, ffserver will skip frames until a key_frame
250 is found. This further reduces the startup delay by not transferring data
251 that will be discarded.
252
253
254 <P>
255 * You may want to adjust the MaxBandwidth in the ffserver.conf to limit
256 the amount of bandwidth consumed by live streams.
257
258
259
260
261 <H2><A NAME="SEC14" HREF="ffserver-doc.html#TOC14">2.8 Why does the ?buffer / Preroll stop working after a time?</A></H2>
262
263 <P>
264 It turns out that (on my machine at least) the number of frames successfully
265 grabbed is marginally less than the number that ought to be grabbed. This
266 means that the timestamp in the encoded data stream gets behind real time.
267 This means that if you say 'preroll 10', then when the stream gets 10
268 or more seconds behind, there is no preroll left.
269
270
271 <P>
272 Fixing this requires a change in the internals in how timestamps are
273 handled.
274
275
276
277
278 <H2><A NAME="SEC15" HREF="ffserver-doc.html#TOC15">2.9 Does the <CODE>?date=</CODE> stuff work.</A></H2>
279
280 <P>
281 Yes (subject to the caution above). Also note that whenever you start
282 ffserver, it deletes the ffm file (if any parameters have changed), thus wiping out what you had recorded
283 before.
284
285
286 <P>
287 The format of the <CODE>?date=xxxxxx</CODE> is fairly flexible. You should use one
288 of the following formats (the 'T' is literal):
289
290
291
292 <PRE>
293 * YYYY-MM-DDTHH:MM:SS (localtime)
294 * YYYY-MM-DDTHH:MM:SSZ (UTC)
295 </PRE>
296
297 <P>
298 You can omit the YYYY-MM-DD, and then it refers to the current day. However
299 note that <SAMP>`?date=16:00:00'</SAMP> refers to 4PM on the current day -- this may be
300 in the future and so unlikely to useful.
301
302
303 <P>
304 You use this by adding the ?date= to the end of the URL for the stream.
305 For example: <SAMP>`http://localhost:8080/test.asf?date=2002-07-26T23:05:00'</SAMP>.
306
307
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309 This document was generated on 28 December 2002 using
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