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// This file is part of the 64k demo project.
// It implements a test backend that simulates jittered audio consumption.
#if !defined(STRIP_ALL)
#include "jittered_audio_backend.h"
#include "audio.h"
#include "ring_buffer.h"
#include <chrono>
#include <cstdlib>
#include <cstring>
#include <random>
#include <thread>
JitteredAudioBackend::JitteredAudioBackend()
: running_(false),
should_stop_(false),
jitter_ms_(5.0f),
base_interval_ms_(10.0f),
min_chunk_frames_(256),
max_chunk_frames_(1024),
total_frames_consumed_(0),
underrun_count_(0) {
}
JitteredAudioBackend::~JitteredAudioBackend() {
shutdown();
}
void JitteredAudioBackend::init() {
// Nothing to initialize
}
void JitteredAudioBackend::start() {
if (running_.load()) return;
should_stop_.store(false);
running_.store(true);
// Start audio thread
audio_thread_ = std::thread(&JitteredAudioBackend::audio_thread_loop, this);
}
void JitteredAudioBackend::shutdown() {
if (!running_.load()) return;
should_stop_.store(true);
if (audio_thread_.joinable()) {
audio_thread_.join();
}
running_.store(false);
}
void JitteredAudioBackend::set_jitter_amount(float jitter_ms) {
jitter_ms_ = jitter_ms;
}
void JitteredAudioBackend::set_base_interval(float interval_ms) {
base_interval_ms_ = interval_ms;
}
void JitteredAudioBackend::set_chunk_size_range(int min_frames, int max_frames) {
min_chunk_frames_ = min_frames;
max_chunk_frames_ = max_frames;
}
void JitteredAudioBackend::audio_thread_loop() {
AudioRingBuffer* ring_buffer = audio_get_ring_buffer();
if (ring_buffer == nullptr) return;
// Random number generator for jitter
std::random_device rd;
std::mt19937 gen(rd());
std::uniform_real_distribution<float> jitter_dist(-jitter_ms_, jitter_ms_);
std::uniform_int_distribution<int> chunk_dist(min_chunk_frames_, max_chunk_frames_);
while (!should_stop_.load()) {
// Calculate jittered wait time
const float jitter = jitter_dist(gen);
const float wait_ms = base_interval_ms_ + jitter;
const int wait_us = (int)(wait_ms * 1000.0f);
if (wait_us > 0) {
std::this_thread::sleep_for(std::chrono::microseconds(wait_us));
}
// Random chunk size
const int chunk_frames = chunk_dist(gen);
const int chunk_samples = chunk_frames * 2; // Stereo
// Read from ring buffer
float* temp_buffer = new float[chunk_samples];
const int read_samples = ring_buffer->read(temp_buffer, chunk_samples);
// Check for underrun
if (read_samples < chunk_samples) {
underrun_count_.fetch_add(1);
}
// Track consumption
total_frames_consumed_.fetch_add(read_samples / 2);
// Notify of frames rendered (for tracking)
on_frames_rendered(read_samples / 2);
delete[] temp_buffer;
}
}
#endif /* !defined(STRIP_ALL) */
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