kc3-lang/SDL/src/audio

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• Hash : 111c3add
  Author :
  Date : 2022-04-10T13:23:51
  

  audio: Resampler optimizations.
  
  - Calculate `j * RESAMPLER_SAMPLES_PER_ZERO_CROSSING` once per loop
    iteration since we use it multiple times.
  - Do the left-wing loop in two sections: while `srcframe < 0` and then
    the remaining calculations when `srcframe >= 0`. This bubbles a conditional
    out of every iteration of a tight loop, giving us a boost. We could
    _probably_ do this to the right-wing loop too, but it's less straightforward
    there.
  - The real win: Use floats instead of doubles. This almost doubles the speed
    of the entire function on Intel CPUs, and for embedded things without
    hardware-level support for doubles, the speedup is enormous. This in
    theory might reduce audio quality, though, and I had to put a check in
    place to avoid a division-by-zero that we avoided at higher precision, but
    this is likely to be worth keeping for at least the Sony PSP and other
    smaller platforms, if not everyone.
  

• Files

• SDL_audio.c
• SDL_audio_c.h
• SDL_audio_resampler_filter.h
• SDL_audiocvt.c
• SDL_audiodev.c
• SDL_audiodev_c.h
• SDL_audiotypecvt.c
• SDL_mixer.c
• SDL_sysaudio.h
• SDL_wave.c
• SDL_wave.h
• aaudio/
• alsa/
• android/
• arts/
• coreaudio/
• directsound/
• disk/
• dsp/
• dummy/
• emscripten/
• esd/
• fusionsound/
• haiku/
• jack/
• nacl/
• nas/
• netbsd/
• openslES/
• os2/
• paudio/
• pipewire/
• psp/
• pulseaudio/
• qsa/
• sndio/
• sun/
• vita/
• wasapi/
• winmm/

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