Additional check on p_first_byte_to_mix.

[vlc] / FAQ

Frequentely Asked Questions for VideoLAN Client
$Id: FAQ,v 1.21 2003/01/22 10:03:17 massiot Exp $

1. Using VLC
============

1.1 How do I read a DVD?
------------------------
Just launch vlc and use the "open disc" command from the graphical
interface. In case of trouble, you may want to use the command line.
For instance, provided your DVD device is /dev/dvd:

    vlc dvd:/dev/dvd


1.2 How do I read an encrypted DVD?
-----------------------------------
It is exactly the same as for a normal DVD. You will need write access to
/dev/dvd, because of the key negociation process.

If you compiled your VLC by hand, please bear in mind that you also need
to install libdvdcss. It can be downloaded from the VideoLAN website. It
used to be distributed in the same package as VLC, but now you must install
them seperately.


1.3 How do I switch to full screen display?
-------------------------------------------
Press 'f' to toggle fullscreen mode. Note that not all video output
devices support full screen.


1.4 How do I hide the mouse cursor?
-----------------------------------
It should disappear after a few seconds if you stop moving the mouse.


1.5 How do I use vlc if I do not want to install Gnome and all this
#@!£% *$@&§% !@# bloat?
-------------------------------------------------------------------
You can run:

    vlc --intf dummy myfile.mpg

Most commands are available from the command line, see vlc --help for
more information.


1.6 VLC eats my buffer cache, how to I use raw device?
------------------------------------------------------
If you do not know what is a raw device, do not even read this answer :-).
There is an experimental support for raw devices in libdvdcss. It needs
that you set up a raw device pointing to your DVD device (under Linux,
use the "raw" utility). Then pass the raw device as second argument, for
instance:

    vlc dvd:/dev/dvd@/dev/raw0


1.7 How do I use VLC as a client for VLS/VLMS streaming?
--------------------------------------------------------
First you must set up a VLS or VLMS stream. Please refer to the
documentation of these programs. Then start VLC:

    vlc udp:

You should not need any option. If you are paranoid and want to control
everything, here is the exact syntax:

    vlc udp:[<server>[:<server port>]][@[<bind address>][:<bind port>]]


1.8 How do I uninstall / reinstall VLC?
---------------------------------------
Why would you want to? ;)

If you are using a source distribution of VLC, for example a tarball or
the CVS, then you have probably used "make install" to install the
compiled VLC. To remove it just "make uninstall". If you want to
install a newer version than the currently installed one, you should
first uninstall the first one. If you deleted the original source tree,
a "make uninstall" in the newer tree should still work.

For binary packages, remove old packages first and install the new ones
(normally this should be handled automagically by your sytem).


1.9 Debian: what should I put in my sources.list for videolan?
--------------------------------------------------------------
deb     http://www.videolan.org/pub/videolan/debian $(ARCH)/
deb-src http://www.videolan.org/pub/videolan/debian sources/


1.10 How can I save my VLC configuration?
-----------------------------------------
Currently, the only way to save the configuration options in VLC is through
the preferences menu in one of the graphical user interface plugins.


1.11 Where does VLC store its config file?
------------------------------------------
Currently, a config file is created on a per user basis (there is no global
configuration file). If you modify the available options in VLC and save the
new configuration, then a configuration file will be created in your user
directory. The precise location of this file depends on the Operating System
you are running:

 * Unices (Linux, etc.): "$(HOME)/.vlc/vlcrc"

 * Windows: "Application Data\vlc\vlcrc"

 * BeOS: "config/settings/vlcrc"


1.12 How do I join an IPv6 multicast stream?
--------------------------------------------
You often have to indicate the interface name on your system, for instance :
 udp:@[FEDC:BA98:7654:3210:FEDC:BA98:7654:3210%eth0]:1234


2. Troubleshooting
==================

2.1 When I start vlc, I do not see any interface coming
-------------------------------------------------------
If you installed a binary package, make sure you also installed an
interface package such as vlc-gtk or vlc-qt. If you installed from
source, make sure the development package for gtk or qt is correctly
installed (often gtk-dev or gtk-devel) and recompile.


2.2 Clicking on "disc" in the interface does not do anything
------------------------------------------------------------
Wait a few seconds. Key cracking can take much time on some discs. If it
still does not work, you can have a more verbose output using "vlc -vvvvv".
Here are a few things to check for:

 * Did you install the libdvdcss package?

 * Do you have write access to your DVD device? For instance:

    chmod 666 /dev/hdc

 * Does your kernel log contain line about your DVD device?

 * Do you have a link from /dev/dvd to your real DVD device? For instance

    ln -s hdc /dev/dvd


2.3 [REMOVED]
-------------

2.4 The video runs but the picture is distorted
-----------------------------------------------
There is probably a problem with the output layer. There are several
ways of troubleshooting it. First, try with another output plugin, for
instance:

   vlc --vout sdl
   vlc --vout x11

Second, change your screen depth and/or definition. It quite often helps.
Lastly, have a look at your XFree86 video driver (nVidia for instance
releases optimized drivers for its boards).


2.5 Video is choppy
-------------------
Your system is too slow to decode all pictures. It might be that your
CPU basically is not fast enough. It can also be that the subsystem is
misconfigured/misdriven, this happens for example under Redhat. Here are
some elements to improve speed:

 * Turn on DMA on your DVD device, for instance:
    hdparm -X34 -d1 /dev/dvd

 * Upgrade to the latest XFree86 version and the latest driver for your
   video board; check that the xvideo plugin is effectively used with
   vlc -vvvv

 * Kill other running applications


2.6 Audio is choppy
-------------------
This is not normal; it is a known problem and is being investigated.


2.7 Audio and video are out of sync
-----------------------------------
This is not normal. Try using another output plugin (for instance --aout dsp),
kill esd or artsd if they are running. This is a known problem and
is being investigated.


2.8 [REMOVED]
-------------

2.9 Sound volume is too low
---------------------------
You can raise it with --volume command line switch or in the preferences
window of your graphical interface.


2.10 I have no image under DirectX
----------------------------------
Check that your video card drivers are in their latest version and that
your DirectX is up-to-date.


2.11 VLC crashes
----------------
Increase the verbosity level (either in the preferences or with a
"-vv" command line option) and look at the debug messages (in the
terminal or in the Messages window).


2.12 I can only play a DVD as root
----------------------------------
Check that as user you have write access to your DVD drive / device.


2.13 I am stuck with option xxx, how do I reset options?
--------------------------------------------------------
Under unices, remove your ~/.videolan/vlcrc; for Windows, remove vlcrc
in the videolan subfolder of your "Application Data" directory.


2.14 I do not have access to the GUI anymore
--------------------------------------------
If you change the default interface module in the preferences menu to a non
GUI module (ie. to a command line interface) and then save the configuration,
the only way to get VLC to show a GUI again is to run it directly from the
command line.
For instance on Windows, you need to open a dos command box, go to the
directory where you installed VLC (usually
c:\Program Files\VideoLAN\VideoLAN Client) and then type "vlc --intf win32"
You will then be able to modify the configuration again and save it.


2.15 I have just upgraded to VLC 0.4.5, and now I do not have any sound
with the streams coming from the VLS!
-----------------------------------------------------------------------
This is a known problem. VLC 0.4.5 and later are now compliant to general
usage regarding A/52 sound, and the new behavior is incompatible with the
previous one. VLS version 0.4.0 and later now fixes this problem. If, for
any reason, you wish to keep VLS 0.3.3, you can still read those streams by
launching VLC (0.4.5 or later) with --vls-backwards-compat.


2.16 NO VIDEO!! or NO AUDIO!!
-----------------------------
DON'T PANIC! Use the verbose mode of vlc to search the problem, you may
either set the verbosity option in the interface preferences or use
the "-v" command line switch to increase the number of report/error
messages given by vlc. If you are not using a terminal, use the Messages
window in the View menu.


3. Ports and features
=====================

3.1 MacOS X port
================

3.1.1 Does VLC support the ATI DVD hardware acceleration cards?
---------------------------------------------------------------
Currently it does not. We would be glad to support them, but we lack technical
information on them.


3.1.2 [REMOVED]
---------------

3.2 Win32 port
==============

3.2.2 When moving the focus to another window, VLC network input stops
working properly!
----------------------------------------------------------------------
This is a known problem with Win 95-class systems. Upgrade to an NT-class
system.


3.3 Planned ports
=================

3.3.1 Do you have plans for a MacOS 9 / OS/2 / &{#!@}~ port?
------------------------------------------------------------
No, nobody reported to be actually working on a MacOS 9 port. If you
feel like you could write it, we would of course welcome it. Currently,
the developers are more interested in supporting the latest Operating
Systems and completing the functionalities.


3.3.2 Does VLC have dxr2 / dxr3 cards support?
----------------------------------------------
This support is currently being developed.


3.3.3 Does VLC support RTP?
---------------------------
Yes. Just use vlc rtp:@<mcast addr>:<local port>.


3.3.4 Does VLC support DVD from all regions?
--------------------------------------------
VLC uses libdvdcss to read all DVD, disregarding their zone. All regions
are supported without any constraint. However, libdvdcss might not be
legal in your country.


3.3.5 How can I take screenshots?
---------------------------------
This is currently unsupported, but will be in a near future. The latest
developments concern recording the video and the audio to a file.
However, under XFree, you may use the "x11" video output to take normal
screen capture of the video displayed by vlc.


4. Legal concerns
=================

4.1 May I use the VideoLAN logo?
--------------------------------
You may freely use the VideoLAN logo using the following copyright:

  Copyright (c) 1996-2002 VideoLAN. This logo or a modified version
  may be used or modified by anyone to refer to the VideoLAN project
  or any product developed by the VideoLAN team, but does not indicate
  endorsement by the project.


4.2 May I redistribute VLC?
---------------------------
You may distribute an original or modified version of VideoLAN as long
as you comply with its license terms. It is the GNU General Public
License Version 2 (referred herein as GPL), and it is in the file named
COPYING in our products.
The easiest way to conform to the GPL is to accompany the product you
want to distribute with its sources. For example, if you plan to
distribute the 0.4.6 binary version you should include:

   http://www.videolan.org/pub/videolan/vlc/0.4.6/vlc-0.4.6.tar.gz
   http://www.videolan.org/pub/videolan/vlc/0.4.6/contrib/

You do not need to bother explaining where the sources are, but the
sources have to share the same media as the products.

They are other ways to comply with the GPL, but this should be the
simplest because it does not rely on a contract.

There is one additional issue you need to take care of. The VLC
binary from our website can also read encrypted DVDs with the help of
the libdvdcss library. Its use is controversial in a few countries
such as the United States because of a law called the DMCA. If you are
unsure about the legality of using and distributing this library in
your country, please consult your lawyer.


5. Miscellaneous
================

5.1 How may I help your project?
--------------------------------
You might either contribute time, material, or money. We are also always
needing some translators. You will find all information you need at
<http://www.videolan.org/contribute.html>.


5.2 Why are your mailing-lists and your website in english?
-----------------------------------------------------------
VideoLAN's developers come from all around the world and english is
the only language they can use to communicate together. Although great
care is given to the translation of our software in various languages,
maintaining translations of our documentation and website costs too much
more time than we can afford.