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actually use pulseaudio (works around several ALSA bugs/problems)

master
Sebastien Bourdeauducq 2023-08-24 00:14:27 +08:00
parent 020469d1a2
commit 1530372180
2 changed files with 19 additions and 8 deletions
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4
README Normal file
View File

@ -0,0 +1,4 @@
* set pulseaudio to 192kHz sample rate:
hardware.pulseaudio.daemon.config = { "default-sample-rate" = 192000; };
* check that sound card is operating at 192kHz:
cat /proc/asound/card0/pcm0c/sub0/hw_params

23
main.cpp
View File

@ -6,6 +6,7 @@
#include <mutex>
#include <vector>
#include <complex>
#include <chrono>
#include <GLFW/glfw3.h>
@ -27,7 +28,11 @@ static int waterfall_width = 1600;
static int waterfall_height = 700;
static unsigned int waterfall_data[1600*700];
static std::atomic<int> fps;
static void dsp_thread() {
using namespace std::literals::chrono_literals;
size_t len = 6400;
std::vector<short int> frames(len);
@ -43,6 +48,8 @@ static void dsp_thread() {
for(size_t i=0; i<shape.size(); ++i)
axes.push_back(i);
std::vector<std::complex<float>> frames_ft(len);
int iterations = 0;
auto last_second = std::chrono::steady_clock::now();
while(!terminate_dsp) {
int read_count = snd_pcm_readi(pcm, frames.data(), len);
if(read_count < 0) {
@ -59,18 +66,17 @@ static void dsp_thread() {
waterfall_data[i] = 0xff000000 | 0x010101*std::min(int(abs(frames_ft[i*len/(4*waterfall_width)])/10000.), 255);
}
}
iterations++;
if((std::chrono::steady_clock::now() - last_second) >= 1s) {
fps = iterations;
iterations = 0;
last_second += 1s;
}
};
}
int main(int argc, char* argv[])
{
if(argc != 2) {
std::cerr << "please specify ALSA device on the command line" << std::endl;
std::cerr << "use arecord -L to list, and select raw device without pulseaudio" << std::endl;
return 1;
}
char* alsa_device = argv[1];
if (!glfwInit()) {
std::cerr << "failed to initialize GLFW" << std::endl;
return 1;
@ -113,7 +119,7 @@ int main(int argc, char* argv[])
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
int err;
if ((err = snd_pcm_open(&pcm, alsa_device, SND_PCM_STREAM_CAPTURE, 0)) < 0) {
if ((err = snd_pcm_open(&pcm, "default", SND_PCM_STREAM_CAPTURE, 0)) < 0) {
std::cerr << "cannot open ALSA device: " << snd_strerror(err) << std::endl;
return 1;
}
@ -200,6 +206,7 @@ int main(int argc, char* argv[])
ImGui::TableNextColumn();
if(ImGui::Button("Exit"))
exit = true;
ImGui::Text("FPS: %d", (int)fps);
ImGui::TableNextColumn();
ImGui::Image((void*)(intptr_t)waterfall, ImVec2(waterfall_width, waterfall_height));
ImGui::EndTable();