下面是一些C代碼中填入,然後使用OpenAL的呈現的音頻數據的內存緩衝區 - 沒有音頻文件
// sudo apt-get install libopenal-dev
//
// gcc -o gen_tone gen_tone.c -lopenal -lm
//
#include <stdio.h>
#include <stdlib.h> // gives malloc
#include <math.h>
#ifdef __APPLE__
#include <OpenAL/al.h>
#include <OpenAL/alc.h>
#elif __linux
#include <AL/al.h>
#include <AL/alc.h>
#endif
ALCdevice * openal_output_device;
ALCcontext * openal_output_context;
ALuint internal_buffer;
ALuint streaming_source[1];
int al_check_error(const char * given_label) {
ALenum al_error;
al_error = alGetError();
if(AL_NO_ERROR != al_error) {
printf("ERROR - %s (%s)\n", alGetString(al_error), given_label);
return al_error;
}
return 0;
}
void MM_init_al() {
const char * defname = alcGetString(NULL, ALC_DEFAULT_DEVICE_SPECIFIER);
openal_output_device = alcOpenDevice(defname);
openal_output_context = alcCreateContext(openal_output_device, NULL);
alcMakeContextCurrent(openal_output_context);
// setup buffer and source
alGenBuffers(1, & internal_buffer);
al_check_error("failed call to alGenBuffers");
}
void MM_exit_al() {
ALenum errorCode = 0;
// Stop the sources
alSourceStopv(1, & streaming_source[0]); // streaming_source
int ii;
for (ii = 0; ii < 1; ++ii) {
alSourcei(streaming_source[ii], AL_BUFFER, 0);
}
// Clean-up
alDeleteSources(1, &streaming_source[0]);
alDeleteBuffers(16, &streaming_source[0]);
errorCode = alGetError();
alcMakeContextCurrent(NULL);
errorCode = alGetError();
alcDestroyContext(openal_output_context);
alcCloseDevice(openal_output_device);
}
void MM_render_one_buffer() {
/* Fill buffer with Sine-Wave */
// float freq = 440.f;
float freq = 850.f;
float incr_freq = 0.1f;
int seconds = 4;
// unsigned sample_rate = 22050;
unsigned sample_rate = 44100;
double my_pi = 3.14159;
size_t buf_size = seconds * sample_rate;
short * samples = malloc(sizeof(short) * buf_size);
printf("\nhere is freq %f\n", freq);
int i=0;
for(; i<buf_size; ++i) {
samples[i] = 32760 * sin((2.f * my_pi * freq)/sample_rate * i);
freq += incr_freq;
// incr_freq += incr_freq;
// freq *= factor_freq;
if (100.0 > freq || freq > 5000.0) {
incr_freq *= -1.0f;
}
}
/* upload buffer to OpenAL */
alBufferData(internal_buffer, AL_FORMAT_MONO16, samples, buf_size, sample_rate);
al_check_error("populating alBufferData");
free(samples);
/* Set-up sound source and play buffer */
// ALuint src = 0;
// alGenSources(1, &src);
// alSourcei(src, AL_BUFFER, internal_buffer);
alGenSources(1, & streaming_source[0]);
alSourcei(streaming_source[0], AL_BUFFER, internal_buffer);
// alSourcePlay(src);
alSourcePlay(streaming_source[0]);
// ---------------------
ALenum current_playing_state;
alGetSourcei(streaming_source[0], AL_SOURCE_STATE, & current_playing_state);
al_check_error("alGetSourcei AL_SOURCE_STATE");
while (AL_PLAYING == current_playing_state) {
printf("still playing ... so sleep\n");
sleep(1); // should use a thread sleep NOT sleep() for a more responsive finish
alGetSourcei(streaming_source[0], AL_SOURCE_STATE, & current_playing_state);
al_check_error("alGetSourcei AL_SOURCE_STATE");
}
printf("end of playing\n");
/* Dealloc OpenAL */
MM_exit_al();
} // MM_render_one_buffer
int main() {
MM_init_al();
MM_render_one_buffer();
}
它也有可能將其轉換爲音頻服務器,呈現音頻,而內存緩衝區是重複填充
有沒有辦法一次播放兩個頻率? – Chromium
以最簡單的方式創建self.player2,方式與self.player相同,它將提供組合輸出。我想可能有辦法將它們左右分開,但是你必須做自己的研究。 –
'audioconv'和'audiosink'有什麼用處? – Chromium