Wrote about sound backends in readme

README.md

@@ -28,8 +28,8 @@ Real-time dynamic light with depth-based casted shadows and normal mapping at 45
 * **Fully automatic C++ build system** No more long lists of source files in your project. The included build system will find included headers and their by name corresponding source files automatically. Just tell it to crawl from main and let it figure out the rest automatically. Different backends for libraries are handled by including the library's project header, telling which backend to use for each platform. Checksums are used to only build what has changed, so there is no need to create a static library for parts of your code.
 * **2D drawing** Pixel exact standard draw calls for lines, rectangles, solid image copy, alpha filtered image drawing, depth buffered drawing, and stencil drawing.
 * **3D rendering** Roughly equivalent to Direct3D 7 with bi-linear texture sampling, mipmapping, lightmaps and alpha filtering when used out of the box, but can be modified to be more like Direct 3D 9 if you apply shading to textures (can use SIMD with multi-threading and be scheduled based on viewing distance).
-* **Occlusion system** The collection of rendering tasks for multi-threading also contains an occlusion grid where indernal shapes can be drawn to skip drawing of triangles, object or whole groups if your engine implements a broad-phase for culling and occlusion tests. This fully dynamic occlusion can then be combined with static optimizations for specific games using information about which regions can be seen from each camera location.
-* **Media layer** Cross-platform media layer designed for robustness. On X11, it uses multi-threading for uploading the canvas, so that you get the same performance that you would get with a GPU graphics API but without needing any graphics drivers. Uses a borderless window for full-screen, so that you can easily access other programs if you get an important e-mail or instant message in the background. Upscaling is done on the CPU to work with any screen resolution without relying on graphics drivers that might give pixels the wrong interpolation or not even exist. Older media layers designed for CTR displays may cause frequency out of range errors when no graphics drivers are installed and the display does not accept the arbitrary selection of resolution. Uses an invisible cursor icon to hide the mouse, so that a crashing program will not take away the cursor when trying to kill the process.
+* **Occlusion system** The collection of rendering tasks for multi-threading also contains an occlusion grid where occlusion shapes can be drawn to skip drawing of triangles, object or whole groups if your engine implements a broad-phase for culling and occlusion tests. This fully dynamic occlusion can then be combined with static optimizations for specific games using information about which regions can be seen from each camera location.
+* **Media layer** Cross-platform media layer designed for robustness. Alsa and WinMM sound backends for full control over sound mixing, without having to call anything system specific yourself. On X11, the window management uses multi-threading for uploading the canvas, so that you get the same performance that you would get with a GPU graphics API but without needing any graphics drivers. Uses a borderless window for full-screen, so that you can easily access other programs if you get an important e-mail or instant message in the background. Upscaling is done on the CPU to work with any screen resolution without relying on graphics drivers that might give pixels the wrong interpolation or not even exist. Older media layers designed for CTR displays may cause frequency out of range errors when no graphics drivers are installed and the display does not accept the arbitrary selection of resolution. Uses an invisible cursor icon to hide the mouse, so that a crashing program will not take away the cursor when trying to kill the process.
 * **Graphical user interface framework** Load a visual interface to your window using a single line of code reading a layout file or string. Get generic handles to components using names or a combination of name and index. Add events by attaching lambda functions to component and window callbacks.
 * **Timers** Get the double precision seconds passed since the first call to the timer, so that you won't have to worry about midnight bugs when the time of day resets.
 * **SIMD abstraction layer** Use simd.h to automatically generate highly efficient SSE, AVX and NEON intrinsics from fully readable math syntax. Your vectorized code will look like a reference implementation and compiling for an unknown target architecture will generate scalar operations that can still give a performance boost by writing your algorithm with basic operations that are most often supported directly in CPU hardware, accessing memory aligned with cache lines, keeping the instruction window packed with tasks, and making it very easy for a compiler's auto-vectorization if something similar with a different name exists in the future.
@@ -46,8 +46,7 @@ All included source code with all their licenses allow both commercial and non-c
 If you are not redistributing the source code, then you do not have to tell anyone that you use this library, because an insincere endorsement has no value.
 
 ## Still a public beta
-Theme, GUI, font and sound APIs are still under active development and may have significant changes before a stable version 1.0 is ready.
-Buffer, file, image, draw, filter, string and time APIs are already quite version stable.
+Theme, GUI, font and sound APIs are still under active development and may have significant changes before a stable version 1.0 is ready, because some code is just a primitive placeholder until the advanced implementation can replace it, and one must try to actually use the library before usability problems become obvious. Buffer, file, image, draw, filter, string and time APIs are however already quite version stable. You can choose to stick with a specific version for each new project, keep updated with the latest changes, or wait for stable version 1.0.
 
 ## How you can help
 * Port to Macintosh or Wayland using the same principles of minimal dependency.
@@ -75,5 +74,5 @@ Future Posix compliant systems should only have a few quirks to sort out if it h
 Macintosh does not have a symbolic link to the binary of the running process, so it would fall back on the current directory when asking for the application folder.
 
 ## Will not target:
-* Mobile phones. Because the constant changes breaking backwards compatibility on mobile platforms would defeat the purpose of using a long-lifetime framework, you will be on your own if you try to use the library for such use cases. You cannot just take something from a desktop and run it on a phone, because mobile platforms require custom C++ compilers, screen rotation, battery saving, knowing when to display the virtual keyboard, security permissions, forced full-screen... Trying to do both at the same time would end up with design compromises in both ends like Microsoft Windows 8 or Ubuntu's Unity lock screen.
+* Mobile phones. Because the constant changes breaking backwards compatibility on mobile platforms would defeat the purpose of using a long-lifetime framework. Mobile platforms require custom C++ compilers, access to signal processors, screen rotation, battery saving, knowing when to display the virtual keyboard, security permissions, forced full-screen... Trying to do both at the same time would end up with design compromises in both ends like Microsoft Windows 8 or Ubuntu's Unity lock screen, so it would be better to just take bits and pieces into a new library built on different design principles.
 * Web frontends. Such a wrapper over this library would not be able to get the power of SIMD intrinsics for defining your own image filters, so you would be better off targeting a GPU shading language from the browser which is more suited for dynamic scripting.