---+!! Enhancements to the Audio API %TOC% ---++ Goals ---+++ Simpler to understand * The interfaces are currently bloated, this makes knowing who the consumers of a particular function or variable are very difficult. * The names of functions need to clearly identify not only what they do, but also what context they are to be called in ---+++ Thread safety * The Codec and Audio thread should share zero state-modifying code. Any state modifying function that one calls should _never_ be called on the other. -- Known problem areas: * pcmbuf_flush_fillpos * pcmbuf_play_stop * pcmbuf_play_start * skip_next_track * In the off chance that there is some data that must be modified by both threads, it must not be performance sensitive, and may be protected by a mutex * Existing use of mutexes to protect functions can be eliminated to improve performance once the above is done. ---+++ Performance The following apply only to performance sensitive sections of code. * Functions should have specific behavior, rather than conditional branches. * Some sacrifices to readability for performance is acceptable in these areas * Keep register usage to a minimum (check in the asm how many registers the compiler is using) ---++ Progress Steps that I've so far taken are in SVN ---+++ PCMBuffer * now behaves more like a typical buffer where consumers are told how much space is left if they reach the end * now uses linked lists instead of circular buffer for the buffer descriptors * performance sensitive code optimized by reading compiled code * trimmed down the API exposed to consumers ---+++ PCM * Reduced usage of pcm_ function calls outside of pcmbuf.c (this probably wants more doing) * Reduce latency by only holding the currently playing chunk in PCM.c not the next one too ---+++ Playback Not much done yet
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r6 - 10 Oct 2007 - 06:52:23 -
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