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Add async init SDL audio device for player to prevent blocking main poller(#4773)

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PioLing
2026-07-06 21:05:02 +08:00
committed by GitHub
parent 5f11d3b3bf
commit d133d6e668
3 changed files with 84 additions and 46 deletions
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78
player/SDLAudioDevice.cpp
View File

@@ -18,47 +18,66 @@ using namespace toolkit;
INSTANCE_IMP(SDLAudioDevice);
SDLAudioDevice::~SDLAudioDevice() {
if (_device) {
SDL_CloseAudioDevice(_device);
if (_init_thread.joinable()) {
_init_thread.join();
}
auto dev = _device.load();
if (dev) {
SDL_CloseAudioDevice(dev);
_device = 0;
}
}
SDLAudioDevice::SDLAudioDevice() {
SDL_AudioSpec wanted_spec;
wanted_spec.freq = DEFAULT_SAMPLERATE;
wanted_spec.format = DEFAULT_FORMAT;
wanted_spec.channels = DEFAULT_CHANNEL;
wanted_spec.silence = 0;
wanted_spec.samples = DEFAULT_SAMPLES;
wanted_spec.userdata = this;
wanted_spec.callback = [](void *userdata, Uint8 *stream, int len) {
SDLAudioDevice *_this = (SDLAudioDevice *) userdata;
_this->onReqPCM((char *) stream, len);
};
// 将 SDL_OpenAudioDevice 放到后台线程异步执行, 防止主线程(SDL事件循环)和 event poller 线程阻塞
// 在Windows下没声卡/设备异常时，SDL_OpenAudioDevice()会阻塞
// 在 Linux(PulseAudio/ALSA) 和 macOS(CoreAudio) 上通常秒回，几乎无开销
_init_thread = std::thread([this]() {
SDL_AudioSpec wanted_spec;
wanted_spec.freq = DEFAULT_SAMPLERATE;
wanted_spec.format = DEFAULT_FORMAT;
wanted_spec.channels = DEFAULT_CHANNEL;
wanted_spec.silence = 0;
wanted_spec.samples = DEFAULT_SAMPLES;
wanted_spec.userdata = this;
wanted_spec.callback = [](void *userdata, Uint8 *stream, int len) {
SDLAudioDevice *_this = (SDLAudioDevice *)userdata;
_this->onReqPCM((char *)stream, len);
};
_device = SDL_OpenAudioDevice(NULL, 0, &wanted_spec, &_audio_config, 0);
if (_device <= 0)
_device = SDL_OpenAudioDevice(NULL, 0, &wanted_spec, &_audio_config, SDL_AUDIO_ALLOW_ANY_CHANGE);
if (_device <= 0) {
throw std::runtime_error("SDL_OpenAudioDevice failed");
}
SDL_AudioSpec audio_config;
auto dev = SDL_OpenAudioDevice(NULL, 0, &wanted_spec, &audio_config, 0);
if (dev <= 0)
dev = SDL_OpenAudioDevice(NULL, 0, &wanted_spec, &audio_config, SDL_AUDIO_ALLOW_ANY_CHANGE);
if (dev <= 0) {
WarnL << "SDL_OpenAudioDevice failed, audio output disabled: " << SDL_GetError();
return;
}
InfoL << "actual audioSpec, " << "freq:" << _audio_config.freq
<< ", format:" << hex << _audio_config.format << dec
<< ", channels:" << (int) _audio_config.channels
<< ", samples:" << _audio_config.samples
<< ", pcm size:" << _audio_config.size;
InfoL << "actual audioSpec, " << "freq:" << audio_config.freq
<< ", format:" << hex << audio_config.format << dec
<< ", channels:" << (int)audio_config.channels
<< ", samples:" << audio_config.samples
<< ", pcm size:" << audio_config.size;
_play_buf.reset(new char[_audio_config.size], [](char *ptr) {
delete[] ptr;
// 先设置 _audio_config 和 _play_buf，再设置 _device (release)
// 这样 addChannel 读到 _device != 0 时，_audio_config 和 _play_buf 已就绪
_audio_config = audio_config;
_play_buf.reset(new char[audio_config.size], [](char *ptr) {
delete[] ptr;
});
_device.store(dev, std::memory_order_release);
});
}
void SDLAudioDevice::addChannel(AudioSRC *chn) {
auto dev = _device.load(std::memory_order_acquire);
if (dev == 0) {
throw std::runtime_error("SDL audio device not available (not ready or no audio device)");
}
lock_guard<recursive_mutex> lck(_channel_mtx);
if (_channels.empty()) {
SDL_PauseAudioDevice(_device, false);
SDL_PauseAudioDevice(dev, false);
}
chn->setOutputAudioConfig(_audio_config);
_channels.emplace(chn);
@@ -67,8 +86,9 @@ void SDLAudioDevice::addChannel(AudioSRC *chn) {
void SDLAudioDevice::delChannel(AudioSRC *chn) {
lock_guard<recursive_mutex> lck(_channel_mtx);
_channels.erase(chn);
if (_channels.empty()) {
SDL_PauseAudioDevice(_device, true);
auto dev = _device.load();
if (_channels.empty() && dev) {
SDL_PauseAudioDevice(dev, true);
}
}

5
player/SDLAudioDevice.h
View File

@@ -13,6 +13,8 @@
#include <mutex>
#include <memory>
#include <atomic>
#include <thread>
#include <stdexcept>
#include <unordered_set>
@@ -40,11 +42,12 @@ private:
void onReqPCM(char *stream, int len);
private:
SDL_AudioDeviceID _device;
std::atomic<SDL_AudioDeviceID> _device{ 0 };
std::shared_ptr<char> _play_buf;
SDL_AudioSpec _audio_config;
std::recursive_mutex _channel_mtx;
std::unordered_set<AudioSRC *> _channels;
std::thread _init_thread;
};
#endif /* SDLAUDIOMIXER_SDLAUDIODEVICE_H_ */

47
player/test_player.cpp
View File

@@ -93,37 +93,52 @@ int main(int argc, char *argv[]) {
}
if (audioTrack) {
auto decoder = std::make_shared<FFmpegDecoder>(audioTrack);
auto audio_player = std::make_shared<AudioPlayer>();
// FFmpeg解码时已经统一转换为16位整型pcm
audio_player->setup(audioTrack->getAudioSampleRate(), audioTrack->getAudioChannel(), AUDIO_S16);
FFmpegSwr::Ptr swr;
try {
auto decoder = std::make_shared<FFmpegDecoder>(audioTrack);
auto audio_player = std::make_shared<AudioPlayer>();
// FFmpeg解码时已经统一转换为16位整型pcm
audio_player->setup(audioTrack->getAudioSampleRate(), audioTrack->getAudioChannel(), AUDIO_S16);
FFmpegSwr::Ptr swr;
decoder->setOnDecode([audio_player, swr](const FFmpegFrame::Ptr &frame) mutable {
if (!swr) {
# if LIBAVCODEC_VERSION_INT >= FF_CODEC_VER_7_1
swr = std::make_shared<FFmpegSwr>(AV_SAMPLE_FMT_S16, &(frame->get()->ch_layout), frame->get()->sample_rate);
decoder->setOnDecode([audio_player, swr](const FFmpegFrame::Ptr &frame) mutable {
if (!swr) {
#if LIBAVCODEC_VERSION_INT >= FF_CODEC_VER_7_1
swr = std::make_shared<FFmpegSwr>(AV_SAMPLE_FMT_S16, &(frame->get()->ch_layout), frame->get()->sample_rate);
#else
swr = std::make_shared<FFmpegSwr>(AV_SAMPLE_FMT_S16, frame->get()->channels, frame->get()->channel_layout, frame->get()->sample_rate);
swr = std::make_shared<FFmpegSwr>(AV_SAMPLE_FMT_S16, frame->get()->channels, frame->get()->channel_layout, frame->get()->sample_rate);
#endif
}
auto pcm = swr->inputFrame(frame);
auto len = pcm->get()->nb_samples * pcm->getChannels() * av_get_bytes_per_sample((enum AVSampleFormat)pcm->get()->format);
audio_player->playPCM((const char *)(pcm->get()->data[0]), MIN(len, frame->get()->linesize[0]));
});
audioTrack->addDelegate([decoder](const Frame::Ptr &frame) { return decoder->inputFrame(frame, false, true); });
}
auto pcm = swr->inputFrame(frame);
auto len = pcm->get()->nb_samples * pcm->getChannels() * av_get_bytes_per_sample((enum AVSampleFormat)pcm->get()->format);
audio_player->playPCM((const char *)(pcm->get()->data[0]), MIN(len, frame->get()->linesize[0]));
});
audioTrack->addDelegate([decoder](const Frame::Ptr &frame) { return decoder->inputFrame(frame, false, true); });
} catch (const std::exception &ex) {
WarnL << "audio output disabled: " << ex.what();
}
}
});
player->setOnShutdown([](const SockException &ex) { WarnL << "play shutdown: " << ex.what(); });
// 不等待track ready再回调播放成功事件，这样可以加快秒开速度
(*player)[Client::kWaitTrackReady] = false;
(*player)[Client::kPlayTrack] = 0;
if (argc > 2) {
(*player)[Client::kRtpType] = atoi(argv[2]);
}
if (argc > 3) {
(*player)[Client::kPlayTrack] = atoi(argv[3]);
}
// 提前触发 SDL 音频设备异步初始化(后台线程)
// 某些平台在无音频设备时 SDL_OpenAudioDevice 会长时间阻塞
// (如 Windows WASAPI 约 16 秒)，提前启动确保 play 回调时已就绪
try {
SDLAudioDevice::Instance();
} catch (const std::exception &ex) {
WarnL << "SDL audio device pre-init failed: " << ex.what();
}
player->play(argv[1]);
SDLDisplayerHelper::Instance().runLoop();
}