Mercurial > sdl-ios-xcode
view docs/html/guidecdromexamples.html @ 3880:74e828c64315 SDL-1.2
Fixed bug #292
I might be on crack here.
It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and
right channels of a stereo stream together, and clamps the new mono channel if
it would overflow.
Shouldn't it be dividing by 2 to average the two sample points instead of
clamping? Otherwise the mono sample point's volume doubles in the conversion.
This would also make the conversion faster, as it replaces two branches per
sample frame with a bitwise shift.
--ryan.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Sun, 24 Sep 2006 15:45:37 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >CDROM Examples</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Examples" HREF="guideexamples.html"><LINK REL="PREVIOUS" TITLE="Audio Examples" HREF="guideaudioexamples.html"><LINK REL="NEXT" TITLE="Time Examples" HREF="guidetimeexamples.html"></HEAD ><BODY CLASS="SECT1" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="guideaudioexamples.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 4. Examples</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="guidetimeexamples.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="GUIDECDROMEXAMPLES" ></A >CDROM Examples</H1 ><P ></P ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="AEN393" ></A >Listing CD-ROM drives</H2 ><P ><PRE CLASS="PROGRAMLISTING" > #include "SDL.h" /* Initialize SDL first */ if ( SDL_Init(SDL_INIT_CDROM) < 0 ) { fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError()); exit(1); } atexit(SDL_Quit); /* Find out how many CD-ROM drives are connected to the system */ printf("Drives available: %d\n", SDL_CDNumDrives()); for ( i=0; i<SDL_CDNumDrives(); ++i ) { printf("Drive %d: \"%s\"\n", i, SDL_CDName(i)); }</PRE ></P ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="AEN397" ></A >Opening the default drive</H2 ><P ><PRE CLASS="PROGRAMLISTING" > SDL_CD *cdrom; CDstatus status; char *status_str; cdrom = SDL_CDOpen(0); if ( cdrom == NULL ) { fprintf(stderr, "Couldn't open default CD-ROM drive: %s\n", SDL_GetError()); exit(2); } status = SDL_CDStatus(cdrom); switch (status) { case CD_TRAYEMPTY: status_str = "tray empty"; break; case CD_STOPPED: status_str = "stopped"; break; case CD_PLAYING: status_str = "playing"; break; case CD_PAUSED: status_str = "paused"; break; case CD_ERROR: status_str = "error state"; break; } printf("Drive status: %s\n", status_str); if ( status >= CD_PLAYING ) { int m, s, f; FRAMES_TO_MSF(cdrom->cur_frame, &m, &s, &f); printf("Currently playing track %d, %d:%2.2d\n", cdrom->track[cdrom->cur_track].id, m, s); }</PRE ></P ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="AEN401" ></A >Listing the tracks on a CD</H2 ><P ><PRE CLASS="PROGRAMLISTING" > SDL_CD *cdrom; /* Assuming this has already been set.. */ int i; int m, s, f; SDL_CDStatus(cdrom); printf("Drive tracks: %d\n", cdrom->numtracks); for ( i=0; i<cdrom->numtracks; ++i ) { FRAMES_TO_MSF(cdrom->track[i].length, &m, &s, &f); if ( f > 0 ) ++s; printf("\tTrack (index %d) %d: %d:%2.2d\n", i, cdrom->track[i].id, m, s); }</PRE ></P ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="AEN405" ></A >Play an entire CD</H2 ><P ><PRE CLASS="PROGRAMLISTING" > SDL_CD *cdrom; /* Assuming this has already been set.. */ // Play entire CD: if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) SDL_CDPlayTracks(cdrom, 0, 0, 0, 0); // Play last track: if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) { SDL_CDPlayTracks(cdrom, cdrom->numtracks-1, 0, 0, 0); } // Play first and second track and 10 seconds of third track: if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) SDL_CDPlayTracks(cdrom, 0, 0, 2, CD_FPS * 10);</PRE ></P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="guideaudioexamples.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="guidetimeexamples.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Audio Examples</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="guideexamples.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Time Examples</TD ></TR ></TABLE ></DIV ></BODY ></HTML >