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\input texinfo @c -*- texinfo -*- |
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@settitle ffserver Documentation |
@titlepage |
@center @titlefont{ffserver Documentation} |
@end titlepage |
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@top |
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@contents |
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@chapter Synopsis |
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ffserver [@var{options}] |
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@chapter Description |
@c man begin DESCRIPTION |
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@command{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 in |
@file{ffserver.conf}). |
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@command{ffserver} receives prerecorded files or FFM streams from some |
@command{ffmpeg} instance as input, then streams them over |
RTP/RTSP/HTTP. |
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An @command{ffserver} instance will listen on some port as specified |
in the configuration file. You can launch one or more instances of |
@command{ffmpeg} and send one or more FFM streams to the port where |
ffserver is expecting to receive them. Alternately, you can make |
@command{ffserver} launch such @command{ffmpeg} instances at startup. |
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Input streams are called feeds, and each one is specified by a |
@code{<Feed>} section in the configuration file. |
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For each feed you can have different output streams in various |
formats, each one specified by a @code{<Stream>} section in the |
configuration file. |
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@section Status stream |
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ffserver supports an HTTP interface which exposes the current status |
of the server. |
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Simply point your browser to the address of the special status stream |
specified in the configuration file. |
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For example if you have: |
@example |
<Stream status.html> |
Format status |
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# Only allow local people to get the status |
ACL allow localhost |
ACL allow 192.168.0.0 192.168.255.255 |
</Stream> |
@end example |
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then the server will post a page with the status information when |
the special stream @file{status.html} is requested. |
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@section What can this do? |
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When properly configured and running, you can capture video and audio in real |
time from a suitable capture card, and stream it out over the Internet to |
either Windows Media Player or RealAudio player (with some restrictions). |
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It can also stream from files, though that is currently broken. Very often, a |
web server can be used to serve up the files just as well. |
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It can stream prerecorded video from .ffm files, though it is somewhat tricky |
to make it work correctly. |
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@section How do I make it work? |
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First, build the kit. It *really* helps to have installed LAME first. Then when |
you run the ffserver ./configure, make sure that you have the |
@code{--enable-libmp3lame} flag turned on. |
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LAME is important as it allows for streaming audio to Windows Media Player. |
Don't ask why the other audio types do not work. |
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As a simple test, just run the following two command lines where INPUTFILE |
is some file which you can decode with ffmpeg: |
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@example |
ffserver -f doc/ffserver.conf & |
ffmpeg -i INPUTFILE http://localhost:8090/feed1.ffm |
@end example |
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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 |
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@example |
http://<linuxbox>:8090/test.asf |
@end example |
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You should (after a short delay) see video and hear audio. |
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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. |
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@section What happens next? |
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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. |
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@section Troubleshooting |
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@subsection I don't hear any audio, but video is fine. |
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Maybe you didn't install LAME, or got your ./configure statement wrong. Check |
the ffmpeg output to see if a line referring to MP3 is present. If not, then |
your configuration was incorrect. If it is, then maybe your wiring is not |
set up correctly. Maybe the sound card is not getting data from the right |
input source. Maybe you have a really awful audio interface (like I do) |
that only captures in stereo and also requires that one channel be flipped. |
If you are one of these people, then export 'AUDIO_FLIP_LEFT=1' before |
starting ffmpeg. |
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@subsection The audio and video lose sync after a while. |
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Yes, they do. |
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@subsection After a long while, the video update rate goes way down in WMP. |
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Yes, it does. Who knows why? |
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@subsection WMP 6.4 behaves differently to WMP 7. |
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Yes, it does. Any thoughts on this would be gratefully received. These |
differences extend to embedding WMP into a web page. [There are two |
object IDs that you can use: The old one, which does not play well, and |
the new one, which does (both tested on the same system). However, |
I suspect that the new one is not available unless you have installed WMP 7]. |
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@section What else can it do? |
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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). |
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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. |
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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.] |
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@section Tips |
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* 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. |
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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. |
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* You may want to adjust the MaxBandwidth in the ffserver.conf to limit |
the amount of bandwidth consumed by live streams. |
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@section Why does the ?buffer / Preroll stop working after a time? |
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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. |
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Fixing this requires a change in the internals of how timestamps are |
handled. |
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@section Does the @code{?date=} stuff work. |
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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. |
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The format of the @code{?date=xxxxxx} is fairly flexible. You should use one |
of the following formats (the 'T' is literal): |
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@example |
* YYYY-MM-DDTHH:MM:SS (localtime) |
* YYYY-MM-DDTHH:MM:SSZ (UTC) |
@end example |
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You can omit the YYYY-MM-DD, and then it refers to the current day. However |
note that @samp{?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. |
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You use this by adding the ?date= to the end of the URL for the stream. |
For example: @samp{http://localhost:8080/test.asf?date=2002-07-26T23:05:00}. |
@c man end |
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@section What is FFM, FFM2 |
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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. |
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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. |
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FFM2 is extensible while maintaining compatibility and should work between |
differing versions of tools. FFM2 is the default. |
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@chapter Options |
@c man begin OPTIONS |
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@include fftools-common-opts.texi |
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@section Main options |
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@table @option |
@item -f @var{configfile} |
Use @file{configfile} instead of @file{/etc/ffserver.conf}. |
@item -n |
Enable no-launch mode. This option disables all the Launch directives |
within the various <Stream> sections. Since ffserver will not launch |
any ffmpeg instances, you will have to launch them manually. |
@item -d |
Enable debug mode. This option increases log verbosity, directs log |
messages to stdout. |
@end table |
@c man end |
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@include config.texi |
@ifset config-all |
@ifset config-avutil |
@include utils.texi |
@end ifset |
@ifset config-avcodec |
@include codecs.texi |
@include bitstream_filters.texi |
@end ifset |
@ifset config-avformat |
@include formats.texi |
@include protocols.texi |
@end ifset |
@ifset config-avdevice |
@include devices.texi |
@end ifset |
@ifset config-swresample |
@include resampler.texi |
@end ifset |
@ifset config-swscale |
@include scaler.texi |
@end ifset |
@ifset config-avfilter |
@include filters.texi |
@end ifset |
@end ifset |
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@chapter See Also |
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@ifhtml |
@ifset config-all |
@url{ffserver.html,ffserver}, |
@end ifset |
@ifset config-not-all |
@url{ffserver-all.html,ffserver-all}, |
@end ifset |
the @file{doc/ffserver.conf} example, |
@url{ffmpeg.html,ffmpeg}, @url{ffplay.html,ffplay}, @url{ffprobe.html,ffprobe}, |
@url{ffmpeg-utils.html,ffmpeg-utils}, |
@url{ffmpeg-scaler.html,ffmpeg-scaler}, |
@url{ffmpeg-resampler.html,ffmpeg-resampler}, |
@url{ffmpeg-codecs.html,ffmpeg-codecs}, |
@url{ffmpeg-bitstream-filters.html,ffmpeg-bitstream-filters}, |
@url{ffmpeg-formats.html,ffmpeg-formats}, |
@url{ffmpeg-devices.html,ffmpeg-devices}, |
@url{ffmpeg-protocols.html,ffmpeg-protocols}, |
@url{ffmpeg-filters.html,ffmpeg-filters} |
@end ifhtml |
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@ifnothtml |
@ifset config-all |
ffserver(1), |
@end ifset |
@ifset config-not-all |
ffserver-all(1), |
@end ifset |
the @file{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) |
@end ifnothtml |
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@include authors.texi |
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@ignore |
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@setfilename ffserver |
@settitle ffserver video server |
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@end ignore |
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@bye |