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audio: Initial bits to enable audio capture support.
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/* | ||
Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org> | ||
This software is provided 'as-is', without any express or implied | ||
warranty. In no event will the authors be held liable for any damages | ||
arising from the use of this software. | ||
Permission is granted to anyone to use this software for any purpose, | ||
including commercial applications, and to alter it and redistribute it | ||
freely. | ||
*/ | ||
#include "SDL.h" | ||
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#ifdef __EMSCRIPTEN__ | ||
#include <emscripten/emscripten.h> | ||
#endif | ||
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#define CAPTURE_SECONDS 5 | ||
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static SDL_AudioSpec spec; | ||
static Uint8 *sound = NULL; /* Pointer to wave data */ | ||
static Uint32 soundlen = 0; /* Length of wave data */ | ||
static Uint32 processed = 0; | ||
static SDL_AudioDeviceID devid = 0; | ||
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void SDLCALL | ||
capture_callback(void *arg, Uint8 * stream, int len) | ||
{ | ||
const int avail = (int) (soundlen - processed); | ||
if (len > avail) { | ||
len = avail; | ||
} | ||
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/*SDL_Log("CAPTURE CALLBACK: %d more bytes\n", len);*/ | ||
SDL_memcpy(sound + processed, stream, len); | ||
processed += len; | ||
} | ||
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void SDLCALL | ||
play_callback(void *arg, Uint8 * stream, int len) | ||
{ | ||
const Uint8 *waveptr = sound + processed; | ||
const int avail = soundlen - processed; | ||
int cpy = len; | ||
if (cpy > avail) { | ||
cpy = avail; | ||
} | ||
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/*SDL_Log("PLAY CALLBACK: %d more bytes\n", cpy);*/ | ||
SDL_memcpy(stream, waveptr, cpy); | ||
processed += cpy; | ||
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len -= cpy; | ||
if (len > 0) { | ||
SDL_memset(stream + cpy, spec.silence, len); | ||
} | ||
} | ||
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static void | ||
loop() | ||
{ | ||
SDL_Event e; | ||
SDL_bool please_quit = SDL_FALSE; | ||
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while (SDL_PollEvent(&e)) { | ||
if (e.type == SDL_QUIT) { | ||
please_quit = SDL_TRUE; | ||
} | ||
} | ||
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if ((!please_quit) && (processed >= soundlen)) { | ||
processed = 0; | ||
if (spec.callback == capture_callback) { | ||
SDL_Log("Done recording, playing back...\n"); | ||
SDL_PauseAudioDevice(devid, 1); | ||
SDL_CloseAudioDevice(devid); | ||
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spec.callback = play_callback; | ||
devid = SDL_OpenAudioDevice(NULL, 0, &spec, &spec, 0); | ||
if (!devid) { | ||
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open an audio device for playback!\n"); | ||
SDL_Quit(); | ||
exit(1); | ||
} | ||
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SDL_PauseAudioDevice(devid, 0); | ||
} else { | ||
SDL_Log("Done playing back.\n"); | ||
please_quit = SDL_TRUE; | ||
} | ||
} | ||
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if (please_quit) { | ||
/* stop playing back, quit. */ | ||
SDL_Log("Shutting down.\n"); | ||
SDL_PauseAudioDevice(devid, 1); | ||
SDL_CloseAudioDevice(devid); | ||
SDL_free(sound); | ||
sound = NULL; | ||
SDL_Quit(); | ||
#ifdef __EMSCRIPTEN__ | ||
emscripten_cancel_main_loop(); | ||
#endif | ||
exit(0); | ||
} | ||
} | ||
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int | ||
main(int argc, char **argv) | ||
{ | ||
/* Enable standard application logging */ | ||
SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO); | ||
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/* Load the SDL library */ | ||
if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO) < 0) { | ||
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError()); | ||
return (1); | ||
} | ||
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/* Android apparently needs a window...? */ | ||
#ifdef __ANDROID__ | ||
SDL_CreateWindow("testaudiocapture", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 320, 240, 0); | ||
#endif | ||
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SDL_Log("Using audio driver: %s\n", SDL_GetCurrentAudioDriver()); | ||
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SDL_zero(spec); | ||
spec.freq = 44100; | ||
spec.format = AUDIO_F32SYS; | ||
spec.channels = 1; | ||
spec.samples = 1024; | ||
spec.callback = capture_callback; | ||
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soundlen = spec.freq * (SDL_AUDIO_BITSIZE(spec.format) / 8) * spec.channels * CAPTURE_SECONDS; | ||
sound = (Uint8 *) SDL_malloc(soundlen); | ||
if (!sound) { | ||
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Out of memory\n"); | ||
SDL_Quit(); | ||
return 1; | ||
} | ||
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devid = SDL_OpenAudioDevice(NULL, 1, &spec, &spec, 0); | ||
if (!devid) { | ||
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open an audio device for capture: %s!\n", SDL_GetError()); | ||
SDL_free(sound); | ||
SDL_Quit(); | ||
exit(1); | ||
} | ||
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SDL_Log("Recording for %d seconds...\n", CAPTURE_SECONDS); | ||
SDL_PauseAudioDevice(devid, 0); | ||
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#ifdef __EMSCRIPTEN__ | ||
emscripten_set_main_loop(loop, 0, 1); | ||
#else | ||
while (1) { loop(); SDL_Delay(16); } | ||
#endif | ||
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return 0; | ||
} | ||
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