faq.docbook

Amarok是一款在LINUX或其他类UNIX操作系统中运行的音频播放器软件。 经过两年开发后

<para>
<command>artsplay foobar.mp3</command>
<command>gst-launch filesrc location=/home/foo/bar.mp3 ! spider ! audioscale ! audioconvert ! alsasink</command>
<command>xine-check</command>
</para>
<para>The output from these commands should help you identify the problems you are having and how to fix them. Please note you may need to use a different sink to test GStreamer (eg. osssink).</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>Can &amarok; output directly to OSS/ALSA?</para>
</question>

<answer>
<para>We already do! Don't forget that the media must be decoded first! You can't just pipe an MP3 to ALSA, all you will get is white-noise. GStreamer is the best choice for most people who want a low-overhead decoding solution, it reads the file, decodes it and pipes the PCM data to ALSA. Exactly like XMMS.</para>
</answer>
</qandaentry>



<qandaentry>
<question>
<para>But! XMMS can output directly to ALSA!</para>
</question>

<answer>
<para>But it decodes it first! GStreamer can output directly to ALSA too! So can xine!</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>The sound stutters, is there anything I can do to improve it?</para>
</question>

<answer>
<para>You can either use the GStreamer engine (it's great!), or tweak aRts. Open Control Center <menuchoice><guimenu>Sound and Multimedia</guimenu> <guimenuitem>Sound System</guimenuitem></menuchoice>. Enable Run with highest possible priority, and increase the size of the Sound buffer: (warning, see the next FAQ!) You should also ensure that your artswrapper is suid:</para>
<para>
<command>su</command>
<command>chmod a+rsx /path/to/kde/bin/artswrapper</command>
<command>killall -9 artsd</command>
</para>
<para>With KDE 3.2.x there are issues with the KDEMultimedia codecs that can cause distorted playback, please see <ulink url="http://bugs.kde.org/show_bug.cgi?id=80497">this bug report</ulink>.
Also, increasing the size of the sound buffer in your .asoundrc alsa configuration file can help a great deal.</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>The CPU usage is high, is there anything I can do to improve it?</para>
</question>

<answer>
<para>Either don't use the aRts-engine, use the GStreamer or xine engines, or address the high CPU usage by installing KDEMultimedia in its entirety to get the faster aRts codecs (eg. libarts_mpeglib.so, etc.)</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>The &amarok; analyzers are really unresponsive!</para>
</question>

<answer>
<para>You are probably using the aRts-engine, either use another engine (the xine-engine has been seriously tweaked to give perfect analyzer-sync), or reduce the size of your aRts buffer in kcontrol, sound system. The lower the buffer the more responsive the visuals. Yes this is a bug, please help us fix it!</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>I have GStreamer installed but when I try to change to the GStreamer engine &amarok; crashes, what gives?</para>
</question>

<answer>
<para>After installing GStreamer you have register it's components, running `gst-register` (sometimes suffixed with a version, so gst-register-0.8) should take care of registering your GStreamer components.</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>I ran gst-register but I still have have GStreamer troubles, what can I do?</para>
</question>

<answer>
<para>You can try the <ulink url="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/faq/html/chapter-using.html">GStreamer FAQ</ulink>. If all else fails you can try the knowledgeable people at the <ulink url="irc://irc.freenode.net/gstreamer">#gstreamer IRC channel</ulink>.</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>&amarok; says that the GStreamer engine cannot play MP3 files, although I have compiled/installed the mad plugin!</para>
</question>

<answer>
<para>Try this (make sure that &amarok; does not run): 
 - <ulink url="http://gstreamer.freedesktop.org/src/gst-ffmpeg/">Download</ulink>, compile and install the ffmpeg package 
 - Run gst-register (you may need to run it twice, as root and as your "normal" user) 
 - Go to your GStreamer plugin directory (you can find it with gst-config / gstreamer-config) 
 - Delete the ffmpeg files (or move them somewhere else) 
 - Run gst-register again 
 - Start &amarok; </para>
</answer>
</qandaentry>


</qandaset>

</sect1>


<sect1 id="faq7">
<title>Development</title>

<qandaset id="development-faq">


<qandaentry>
<question>
<para>How do I get a cvs/svn version of &amarok;?</para>
</question>

<answer>
<para><ulink url="http://amarok.kde.org/amarokwiki/index.php/Installation_HowTo#Building_SVN_Amarok">How to obtain and build SVN &amarok;</ulink></para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>I've found a bug / I've got a great idea for &amarok;!</para>
</question>

<answer>
<para>Please report it at <ulink url="http://bugs.kde.org/">bugs.kde.org</ulink>, if you have a list of suggestions/wishes it may be best to send them to our mailing list: <email>[e-mail]</email> </para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>Do you accept patches?</para>
</question>

<answer>
<para>Happily! Your best course of action is to let us know what you plan to do before you do any work so we can discuss it, but don't fret we haven't turned down a patch yet! Discussion is mostly to help you patch the correct bits of &amarok;. Then either submit a patch to the mailing list, or commit if you have svn access. However, please let us know before you commit new features to svn! If you have a bug fix then just go ahead, this is open source after all :)</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>Why did you choose the name &amarok;?</para>
</question>

<answer>
<para>&amarok; is an album by British composer Mike Oldfield. I happen to like it a lot, and I think the name's got a nice sound. Plus, of course, it contains the all important “K”.. :) </para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>Is it &amarok;, AmaroK or Amarok?</para>
</question>

<answer>
<para>It is &amarok;! Yes, we understand this is unconventional ;-)</para>
</answer>
</qandaentry>


</qandaset>

</sect1>


<sect1 id="faq8">
<title>Tips and Tricks</title>

<qandaset id="tipsandtricks-faq">


<qandaentry>
<question>
<para>How do I use &amarok; as an alarm clock?</para>
</question>

<answer>
<para>Actually, thanks to the magic of DCOP you already can :) Simply set an alarm in your favorite calendar program and tell it to run the following command: 
<command>dcop amarok player play</command>
</para>
<para>This command will tell &amarok; to start playing. Make sure that &amarok; is running before you go to bed, and you should wake up to the merry tune of whatever you pressed stop on before going to bed.</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>How do I get what &amarok; is playing right now, when I'm on another computer?</para>
</question>

<answer>
<para>If you have a properly set up ssh environment, you can use that to get the information. The following command will return the Now Playing string.
<command>ssh -i ~/.ssh/id_rsa yourip dcop --user yourusername amarok player nowPlaying</command>
</para>
<para>Make sure that you replace yourip with your IP and yourusername with your username. Also note that this expects your identification to be found in the ~/.ssh/id_rsa file.</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>What kind of tricks can the Player Window do?</para>
</question>

<answer>
<para>The &amarok; player analyzers can be detached from the Player Window. By pressing d on your keyboard the active analyzer will open in an independent, re-sizeable window.</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>What kind of tricks can the Playlist Window do?</para>
</question>

<answer>
<para>Holding Control and clicking the right mouse button enqueues files in the order in which you clicked them. 
Pressing Enter after making a playlist search will play the first search item and will clear the search.</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>I see the Player Window and Playlist Window have neat tricks, what about the tray icon?</para>
</question>

<answer>
<para>Hovering your mouse on the icon will display a nice popup with current track information.
Clicking the middle mouse button on the icon play-pauses the current track.
Scrolling the mouse wheel changes volume.
Holding Shift while scrolling the mouse wheel seeks through the current track.
Holding Control while scrolling the mouse wheel will skip through tracks in the playlist.
Dragging and dropping items into the tray icon opens a pop up menu allowing you to choose from three options, Append to Playlist, Append and Play, and Queue after Current Track.
Tray icon is also a song position indicator.</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>Where do I find the settings for &amarok;?</para>
</question>

<answer>
<para>~/.kde/share/apps/amarok 
~/.kde/share/config/amarokrc</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>How do I disable a browser section in &amarok;?</para>
</question>

<answer>
<para>Clicking with the &RMB; on any browser title shows up a list of visible browsers. You can use this list to disable/re-enable any browsers available.</para>
</answer>
</qandaentry>


</qandaset>

</sect1>


<sect1 id="faq9">
<title>General Questions</title>

<qandaset id="general-questions-faq">


<qandaentry>
<question>
<para>How Do I use an external MySQL database with &amarok;?</para>
</question>

<answer>
<para>See <ulink url="http://amarok.kde.org/amarokwiki/index.php/MySQL_HowTo">MySQL HowTo</ulink>.</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>My $HOME is located on NFS. After startup, &amarok; fails to build the Collection, printing many database errors to the console. What to do?</para>
</question>

<answer>
<para>The internal SQLite database which &amarok; uses by default does not work on NFS. You must either link your ~/.kde/share/apps/amarok directory to a local drive, or use the MySQL support.</para>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>How can I rip/encode Audio-CDs with &amarok;?</para>
</question>

<answer>
<para>Insert your CD, then click on "Play Audio CD" in the menu. The File-Browser will come up and show a tree with several folders. For normal ripping, go to the "wav" folder, select some tracks and drag them to the desired destination in a Konqueror window. For automatic encoding, drag files from the "mp3" or "ogg" folder instead.</para>
<note><para>CD-ripping requires the "AudioCD KIO-slave" to be installed. It is part of KDE-Multimedia.</para></note>
</answer>
</qandaentry>


<qandaentry>
<question>
<para>How are track ratings determined?</para>
</question>

<answer>
<para>&amarok; assigns a rating (a number 1-100) to a song based on how many times you've listened to it and whether you skip the song without it finishing. Every time the song finishes playing, the rating is changed. The code for changing the rating is in collectiondb.cpp. As of version 1.2.2, it was on line 1181, though you can find it by searching for "CollectionDB::addSongPercentage". 
When defining a score for a track which has never been played before, &amarok; uses the calculation  
score = ( ( 50 + percentage ) / 2 )</para>
<para>This sets the score equal to a number from 25-75, depending on how far through the song was allowed to play. For example, if the user stops or skips the song after only 25% of it has played, the score will be set to (50+25)/2, or 37.5. Scores are displayed as integers, however, so this number is rounded to the nearest integer before being displayed. The score is kept internally as a floating point number however, since after a song has been played several times, it may be impossible to alter the score by more than a point with a single play (see below). 
When defining a score for a track which has been played before, the calculation is a bit more complicated. In the source, it is 
   score = ( ( values[2].toDouble() * values.first().toInt() ) + percentage ) / ( values.first().toInt() + 1 );</para>
<para>Substituting in the values from this line:</para>
<programlisting>
   QStringList values = query( QString(
           "SELECT playcounter, createdate, percentage FROM statistics "
           "WHERE url = '%1';" )
           .arg( escapeString( url ) ) );
</programlisting>
<para>We have 
   score = ( ( statistics_percentage.toDouble() * PlayCounter.toInt() ) + percentage ) / ( PlayCounter.toInt() + 1 );
</para>