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The perceived loudness change of a change in volume depends on the listening volume: at high volumes a 1 dB increment is noticeable, but at low volumes a larger increment is needed to get a comparable change in loudness. Perceptual volume adjustment accounts for this fact, and divides the hardware volume range into a number of steps. Each step changes the dB volume by a variable amount, with most of the steps concentrated at higher volumes. This makes it possible to sweep over the entire hardware volume range quickly, without losing the ability to finely adjust the volume at normal listening levels. Use "Volume Adjustment Mode" in the system settings menu to select perceptual volume mode. The number of steps used is controlled by "Number of Volume Steps". (Number of steps has no effect in direct adjustment mode.) It's still possible to set a specific dB volume level from the sound settings menu when perceptual volume is enabled, and perceptual volume does not affect the volume displayed by themes. Change-Id: I6f91fd3f7c5e2d323a914e47b5653033e92b4b3b |
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include | ||
progs | ||
SDL_image | ||
SDL_mixer | ||
src | ||
COPYING | ||
CREDITS | ||
main.c | ||
NOTES | ||
README | ||
README-SDL.txt | ||
README.Porting | ||
redefines.txt | ||
sdl.make | ||
SOURCES | ||
SOURCES.duke | ||
SOURCES.quake | ||
SOURCES.wolf | ||
wrappers.c |
See NOTES for Rockbox-specific porting notes. The original README is below: Simple DirectMedia Layer (SDL) Version 1.2 --- http://www.libsdl.org/ This is the Simple DirectMedia Layer, a general API that provides low level access to audio, keyboard, mouse, joystick, 3D hardware via OpenGL, and 2D framebuffer across multiple platforms. The current version supports Linux, Windows CE/95/98/ME/XP/Vista, BeOS, MacOS Classic, Mac OS X, FreeBSD, NetBSD, OpenBSD, BSD/OS, Solaris, IRIX, and QNX. The code contains support for Dreamcast, Atari, AIX, OSF/Tru64, RISC OS, SymbianOS, Nintendo DS, and OS/2, but these are not officially supported. SDL is written in C, but works with C++ natively, and has bindings to several other languages, including Ada, C#, Eiffel, Erlang, Euphoria, Guile, Haskell, Java, Lisp, Lua, ML, Objective C, Pascal, Perl, PHP, Pike, Pliant, Python, Ruby, and Smalltalk. This library is distributed under GNU LGPL version 2, which can be found in the file "COPYING". This license allows you to use SDL freely in commercial programs as long as you link with the dynamic library. The best way to learn how to use SDL is to check out the header files in the "include" subdirectory and the programs in the "test" subdirectory. The header files and test programs are well commented and always up to date. More documentation is available in HTML format in "docs/index.html", and a documentation wiki is available online at: http://www.libsdl.org/cgi/docwiki.cgi The test programs in the "test" subdirectory are in the public domain. Frequently asked questions are answered online: http://www.libsdl.org/faq.php If you need help with the library, or just want to discuss SDL related issues, you can join the developers mailing list: http://www.libsdl.org/mailing-list.php Enjoy! Sam Lantinga (slouken@libsdl.org)