我有興趣聽到這個問題的答案。我的解決方案是在iOS中使用OpenAL製作我自己的音頻服務器,OpenAL開箱即可呈現音頻緩衝區 - 基本上只有一個線程處理消耗從服務器發送的音頻流 - 另一個線程用於運行您自己的OpenAL服務器我在這裏概述:
#import <OpenAL/al.h>
#import <OpenAL/alc.h>
#import <AudioToolbox/ExtendedAudioFile.h>
-(void) init_openal {
openal_device = alcOpenDevice(NULL);
if (openal_device != NULL) {
// create context
openal_context = alcCreateContext(openal_device, 0);
if (openal_context != NULL) {
// activate this new context
alcMakeContextCurrent(openal_context);
} else {
NSLog(@"STR_OPENAL ERROR - failed to create context");
return;
}
} else {
NSLog(@"STR_OPENAL ERROR - failed to get audio device");
return;
}
alGenBuffers(MAX_OPENAL_QUEUE_BUFFERS, available_AL_buffer_array); // allocate the buffer array to given number of buffers
alGenSources(1, & streaming_source);
printf("STR_OPENAL streaming_source starts with %u\n", streaming_source);
printf("STR_OPENAL initialization of available_AL_buffer_array_curr_index to 0\n");
available_AL_buffer_array_curr_index = 0;
self.previous_local_lpcm_buffer = 0;
[self get_next_buffer];
} // init_openal
// calling init and retrieving buffers logic left out goes here
-(void) inner_run {
ALenum al_error;
// UN queue used buffers
ALint buffers_processed = 0;
alGetSourcei(streaming_source, AL_BUFFERS_PROCESSED, & buffers_processed); // get source parameter num used buffs
while (buffers_processed > 0) { // we have a consumed buffer so we need to replenish
NSLog(@"STR_OPENAL inner_run seeing consumed buffer");
ALuint unqueued_buffer;
alSourceUnqueueBuffers(streaming_source, 1, & unqueued_buffer);
// about to decrement available_AL_buffer_array_curr_index
available_AL_buffer_array_curr_index--;
printf("STR_OPENAL to NEW %d with unqueued_buffer %d\n",
available_AL_buffer_array_curr_index,
unqueued_buffer);
available_AL_buffer_array[available_AL_buffer_array_curr_index] = unqueued_buffer;
buffers_processed--;
}
// queue UP fresh buffers
if (available_AL_buffer_array_curr_index >= MAX_OPENAL_QUEUE_BUFFERS) {
printf("STR_OPENAL about to sleep since internal OpenAL queue is full\n");
[NSThread sleepUntilDate:[NSDate dateWithTimeIntervalSinceNow: SLEEP_ON_OPENAL_QUEUE_FULL]];
} else {
NSLog(@"STR_OPENAL YYYYYYYYY available_AL_buffer_array_curr_index %d MAX_OPENAL_QUEUE_BUFFERS %d",
available_AL_buffer_array_curr_index,
MAX_OPENAL_QUEUE_BUFFERS
);
ALuint curr_audio_buffer = available_AL_buffer_array[available_AL_buffer_array_curr_index];
ALsizei size_buff;
ALenum data_format;
ALsizei sample_rate;
size_buff = MAX_SIZE_CIRCULAR_BUFFER; // works nicely with 1016064
sample_rate = lpcm_output_sampling_frequency;
data_format = AL_FORMAT_STEREO16; // AL_FORMAT_STEREO16 == 4355 (0x1103) --- AL_FORMAT_MONO16
printf("STR_OPENAL curr_audio_buffer is %u data_format %u size_buff %u\n",
curr_audio_buffer,
data_format,
size_buff
);
// write_output_file([TS_ONLY_delete_this_var_temp_aif_fullpath
// cStringUsingEncoding:NSUTF8StringEncoding], curr_lpcm_buffer,
// curr_lpcm_buffer_sizeof);
if (self.local_lpcm_buffer == self.previous_local_lpcm_buffer) {
printf("STR_OPENAL NOTICE - need to throttle up openal sleep duration seeing same value for local_lpcm_buffer %d - so will skip loading into alBufferData\n",
(int) self.local_lpcm_buffer);
} else {
NSLog(@"STR_OPENAL about to call alBufferData curr_audio_buffer %d local_lpcm_buffer address %d local_aac_index %d",
curr_audio_buffer,
(int) self.local_lpcm_buffer,
self.local_aac_index);
// copy audio data into curr_buffer
alBufferData(curr_audio_buffer, data_format, self.local_lpcm_buffer, size_buff, sample_rate); // curr_audio_buffer is an INT index determining which buffer to use
self.previous_local_lpcm_buffer = self.local_lpcm_buffer;
alSourceQueueBuffers(streaming_source, 1, & curr_audio_buffer);
printf("STR_OPENAL about to increment available_AL_buffer_array_curr_index from OLD %d",
available_AL_buffer_array_curr_index);
available_AL_buffer_array_curr_index++;
printf("STR_OPENAL available_AL_buffer_array_curr_index to NEW %d\n", available_AL_buffer_array_curr_index);
}
al_error = alGetError();
if(AL_NO_ERROR != al_error)
{
NSLog(@"STR_OPENAL ERROR - alSourceQueueBuffers error: %s", alGetString(al_error));
return;
}
ALenum current_playing_state;
alGetSourcei(streaming_source, AL_SOURCE_STATE, & current_playing_state); // get source parameter STATE
al_error = alGetError();
if(AL_NO_ERROR != al_error)
{
NSLog(@"STR_OPENAL ERROR - alGetSourcei error: %s", alGetString(al_error));
return;
}
if (AL_PLAYING != current_playing_state) {
ALint buffers_queued = 0;
alGetSourcei(streaming_source, AL_BUFFERS_QUEUED, & buffers_queued); // get source parameter num queued buffs
NSLog(@"STR_OPENAL NOTICE - play is NOT AL_PLAYING: %x, buffers_queued: %d", current_playing_state, buffers_queued);
if (buffers_queued > 0 && NO == self.streaming_paused) {
// restart play
NSLog(@"STR_OPENAL about to restart play");
alSourcePlay(streaming_source);
al_error = alGetError();
if (AL_NO_ERROR != al_error) {
NSLog(@"STR_OPENAL ERROR - alSourcePlay error: %s", alGetString(al_error));
}
}
}
if (self.last_aac_index == self.local_aac_index && available_AL_buffer_array_curr_index == 0) {
NSLog(@"STR_OPENAL reached end of event tell parent");
[self send_running_condition_message_to_parent: rendered_last_buffer];
flag_continue_running = false; // terminate since all rendering work is done
} else {
[self get_next_buffer];
}
}
} // inner_run
ty你的代碼:D但openAL api更難理解。所以你有你的streaming_source並將它傳遞給unqueued_buffer?我嘗試瞭解這些代碼,但我必須在OpenAL中使用低(更好的0)體驗。有沒有「更容易」的建議? – Tony 2014-09-25 17:15:29