From c70a211997bcb3c582f25e9648a09995484dd63d Mon Sep 17 00:00:00 2001 From: Fabrice Bellard Date: Tue, 19 Nov 2002 19:47:50 +0000 Subject: ffserver documentation update Originally committed as revision 1234 to svn://svn.ffmpeg.org/ffmpeg/trunk --- doc/ffserver-doc.html | 306 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 306 insertions(+) create mode 100644 doc/ffserver-doc.html (limited to 'doc/ffserver-doc.html') diff --git a/doc/ffserver-doc.html b/doc/ffserver-doc.html new file mode 100644 index 0000000000..8e5c9f7d95 --- /dev/null +++ b/doc/ffserver-doc.html @@ -0,0 +1,306 @@ + + + + +FFserver Documentation + + +

FFserver Documentation

+

+

+

Table of Contents

+ +

+ +

+FFserver Documentation + + + + +

1. Introduction

+ +

+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 ffserver.conf). + + +

+This documentation covers only the streaming aspects of ffserver / +ffmpeg. All questions about parameters for ffmpeg, codec questions, +etc. are not covered here. Read `ffmpeg-doc.[texi|html]' for more +information. + + + + +

2. QuickStart

+ +

+[Contributed by Philip Gladstone, philip-ffserver at gladstonefamily dot net] + + + + +

2.1 What can this do?

+ +

+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). + + +

+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. + + + + +

2.2 What do I need?

+ +

+I use Linux on a 900MHz Duron with a cheapo Bt848 based TV capture card. I'm +using stock linux 2.4.17 with the stock drivers. [Actually that isn't true, +I needed some special drivers from my motherboard based sound card.] + + +

+I understand that FreeBSD systems work just fine as well. + + + + +

2.3 How do I make it work?

+ +

+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 --enable-mp3lame +flag turned on. + + +

+LAME is important as it allows streaming of audio to Windows Media Player. Don't +ask why the other audio types do not work. + + +

+As a simple test, just run the following two command lines: + + + +

+./ffserver -f doc/ffserver.conf &
+./ffmpeg http://localhost:8090/feed1.ffm
+
+ +

+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 + + + +

+    http://<linuxbox>:8090/test.asf
+
+ +

+You should see (after a short delay) video and hear audio. + + +

+WARNING: trying to stream test1.mpg doesn't work with WMP as it tries to +transfer the entire file before starting to play. + + + + +

2.4 What happens next?

+ +

+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. + + + + +

2.5 Troubleshooting

+ + + +

2.5.1 I don't hear any audio, but video is fine

+ +

+Maybe you didn't install LAME, or get your ./configure statement right. 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 +setup 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. + + + + +

2.5.2 The audio and video loose sync after a while.

+ +

+Yes, they do. + + + + +

2.5.3 After a long while, the video update rate goes way down in WMP.

+ +

+Yes, it does. Who knows why? + + + + +

2.5.4 WMP 6.4 behaves differently to WMP 7.

+ +

+Yes, it does. Any thoughts on this would be gratefully received. These +differences extend to embedding WMP into a web page. [There are two +different object ids that you can use, one of them -- the old one -- cannot +play very well, and the new one works well (both on the same system). However, +I suspect that the new one is not available unless you have installed WMP 7]. + + + + +

2.6 What else can it do?

+ +

+There seems to be a bunch of code that allows you to replay previous +video. I've never tried it, so it probably doesn't work properly. YMMV. +In fact, in order to get some level of stability, ffserver now deletes +all the previously sent video whenever it restarts. + + +

+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 the +ffserver.conf for a list of the currently available controls. + + +

+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.] + + + + +

2.7 Tips

+ +

+* 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 real time. 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 says that the +stream should start 5 seconds in the past -- and so the first 5 seconds +of the stream is sent as fast as the network will allow. It will then +slow down to real time. This noticeably improves the startup experience. + + +

+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. + + +

+* You may want to adjust the MaxBandwidth in the ffserver.conf to limit +the amount of bandwidth consumed by live streams. + + + + +

2.8 Why does the ?buffer / Preroll stop working after a time?

+ +

+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 real time. +This means that if you say 'preroll 10', then when the stream gets 10 +or more seconds behind, there is no preroll left. + + +

+Fixing this requires a require in the internals in how timestampts are +handled. + + + + +

2.9 Does the ?date= stuff work.

+ +

+Yes (subject to the caution above). Also note that whenever you start +ffserver, it deletes the ffm file, thus wiping out what you had recorded +before. This behaviour is a temporary fix to various crashes. The aim is +to fix it so that the old data is saved if possible. + + +

+The format of the ?date=xxxxxx is fairly flexible. You should use one +of the following formats (the 'T' is literal): + + + +

+* YYYY-MM-DDTHH:MM:SS     (localtime)
+* YYYY-MM-DDTHH:MM:SSZ    (UTC)
+
+ +

+You can omit the YYYY-MM-DD, and then it refers to the current day. However +note that `?date=16:00:00' refers to 4PM on the current day -- this may be +in the future and so unlikely to useful. + + +

+You use this by adding the ?date= to the end of the URL for the stream. +For example: `http://localhost:8080/test.asf?date=2002-07-26T23:05:00'. + + +

+This document was generated on 19 November 2002 using +texi2html 1.56k. + + -- cgit v1.2.3