mirror of https://github.com/encounter/SDL.git
Generalized the audio resampling hint for other resampling methods in the future
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@ -780,36 +780,26 @@ extern "C" {
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*
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* If available, SDL can use libsamplerate ( http://www.mega-nerd.com/SRC/ )
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* to handle audio resampling. There are different resampling modes available
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* that produce different levels of quality, possibly using more CPU.
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* that produce different levels of quality, using more CPU.
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*
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* If this hint isn't specified to a valid setting, or libsamplerate isn't
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* available, SDL will act as if this hint was set to "fast".
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* available, SDL will use the default, internal resampling algorithm.
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*
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* Note that this is currently only applicable to resampling audio that is
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* being written to a device for playback or audio being read from a device
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* for capture. SDL_AudioCVT always uses the "fast" resampler (although this
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* for capture. SDL_AudioCVT always uses the default resampler (although this
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* might change for SDL 2.1).
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*
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* Most things can probably live with the "fast" resampler, but if quality
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* is important or you can spare some CPU cycles, the other options are
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* worth exploring!
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*
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* libsamplerate's interpolators, that these hints map to, are explained here:
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* http://www.mega-nerd.com/SRC/api_misc.html#Converters
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*
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* This hint is only checked at audio subsystem init time and changes to it
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* at other times are ignored.
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* This hint is currently only checked at audio subsystem initialization.
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*
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* This variable can be set to the following values:
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*
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* "default" - Use SDL's internal, resampler. (Default when not set. low quality, fast.)
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* "linear" - Use libsamplerate's Linear interpolator (low quality, fast).
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* "zero_order_hold" - Use libsamplerate's Zero Order Hold interpolator (low quality, fast).
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* "sinc_fastest" - Use libsamplerate's fastest (lowest quality) sinc interpolator.
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* "sinc_medium" - Use libsamplerate's medium quality sinc interpolator.
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* "sinc_best" - Use libsamplerate's best quality sinc interpolator.
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* "0" or "default" - Use SDL's internal resampling (Default when not set - low quality, fast)
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* "1" or "fast" - Use fast, slightly higher quality resampling, if available
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* "2" or "medium" - Use medium quality resampling, if available
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* "3" or "best" - Use high quality resampling, if available
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*/
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#define SDL_HINT_AUDIO_RESAMPLER_MODE "SDL_AUDIO_RESAMPLER_MODE"
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#define SDL_HINT_AUDIO_RESAMPLING_MODE "SDL_AUDIO_RESAMPLING_MODE"
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/**
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* \brief An enumeration of hint priorities
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@ -123,22 +123,18 @@ const char* (*SRC_src_strerror)(int error) = NULL;
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static SDL_bool
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LoadLibSampleRate(void)
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{
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const char *hint = SDL_GetHint(SDL_HINT_AUDIO_RESAMPLER_MODE);
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const char *hint = SDL_GetHint(SDL_HINT_AUDIO_RESAMPLING_MODE);
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SRC_available = SDL_FALSE;
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SRC_converter = 0;
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if (!hint || (SDL_strcasecmp(hint, "default") == 0)) {
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if (!hint || *hint == '0' || SDL_strcasecmp(hint, "default") == 0) {
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return SDL_FALSE; /* don't load anything. */
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} else if (SDL_strcasecmp(hint, "linear") == 0) {
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SRC_converter = SRC_LINEAR;
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} else if (SDL_strcasecmp(hint, "zero_order_hold") == 0) {
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SRC_converter = SRC_ZERO_ORDER_HOLD;
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} else if (SDL_strcasecmp(hint, "sinc_fastest") == 0) {
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} else if (*hint == '1' || SDL_strcasecmp(hint, "fast") == 0) {
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SRC_converter = SRC_SINC_FASTEST;
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} else if (SDL_strcasecmp(hint, "sinc_medium") == 0) {
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} else if (*hint == '2' || SDL_strcasecmp(hint, "medium") == 0) {
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SRC_converter = SRC_SINC_MEDIUM_QUALITY;
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} else if (SDL_strcasecmp(hint, "sinc_best") == 0) {
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} else if (*hint == '3' || SDL_strcasecmp(hint, "best") == 0) {
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SRC_converter = SRC_SINC_BEST_QUALITY;
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} else {
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return SDL_FALSE; /* treat it like "default", don't load anything. */
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