SDL/test/testaudiorecording.c

/*
  Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely.
*/

#define SDL_MAIN_USE_CALLBACKS 1
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>
#include <SDL3/SDL_test.h>

static SDL_Window *window = NULL;
static SDL_Renderer *renderer = NULL;
static SDL_AudioStream *stream_in = NULL;
static SDL_AudioStream *stream_out = NULL;
static SDLTest_CommonState *state = NULL;

SDL_AppResult SDL_AppInit(void **appstate, int argc, char **argv)
{
    SDL_AudioDeviceID *devices;
    SDL_AudioSpec outspec;
    SDL_AudioSpec inspec;
    SDL_AudioDeviceID device;
    SDL_AudioDeviceID want_device = SDL_AUDIO_DEVICE_DEFAULT_RECORDING;
    const char *devname = NULL;
    int i;

    /* this doesn't have to run very much, so give up tons of CPU time between iterations. */
    SDL_SetHint(SDL_HINT_MAIN_CALLBACK_RATE, "15");

    /* Initialize test framework */
    state = SDLTest_CommonCreateState(argv, 0);
    if (!state) {
        return SDL_APP_SUCCESS;
    }

    /* Parse commandline */
    for (i = 1; i < argc;) {
        int consumed;

        consumed = SDLTest_CommonArg(state, i);
        if (!consumed) {
            if (!devname) {
                devname = argv[i];
                consumed = 1;
            }
        }
        if (consumed <= 0) {
            static const char *options[] = { "[device_name]", NULL };
            SDLTest_CommonLogUsage(state, argv[0], options);
            return SDL_APP_FAILURE;
        }

        i += consumed;
    }

    /* Load the SDL library */
    if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO)) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
        return SDL_APP_SUCCESS;
    }

    if (!SDL_CreateWindowAndRenderer("testaudiorecording", 320, 240, 0, &window, &renderer)) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create SDL window and renderer: %s\n", SDL_GetError());
        return SDL_APP_SUCCESS;
    }
    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
    SDL_RenderClear(renderer);
    SDL_RenderPresent(renderer);

    SDL_Log("Using audio driver: %s\n", SDL_GetCurrentAudioDriver());

    devices = SDL_GetAudioRecordingDevices(NULL);
    for (i = 0; devices[i] != 0; i++) {
        const char *name = SDL_GetAudioDeviceName(devices[i]);
        SDL_Log(" Recording device #%d: '%s'\n", i, name);
        if (devname && (SDL_strcmp(devname, name) == 0)) {
            want_device = devices[i];
        }
    }

    if (devname && (want_device == SDL_AUDIO_DEVICE_DEFAULT_RECORDING)) {
        SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION, "Didn't see a recording device named '%s', using the system default instead.\n", devname);
        devname = NULL;
    }

    /* DirectSound can fail in some instances if you open the same hardware
       for both recording and output and didn't open the output end first,
       according to the docs, so if you're doing something like this, always
       open your recording devices second in case you land in those bizarre
       circumstances. */

    SDL_Log("Opening default playback device...\n");
    device = SDL_OpenAudioDevice(SDL_AUDIO_DEVICE_DEFAULT_PLAYBACK, NULL);
    if (!device) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open an audio device for playback: %s!\n", SDL_GetError());
        SDL_free(devices);
        return SDL_APP_FAILURE;
    }
    SDL_PauseAudioDevice(device);
    SDL_GetAudioDeviceFormat(device, &outspec, NULL);
    stream_out = SDL_CreateAudioStream(&outspec, &outspec);
    if (!stream_out) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create an audio stream for playback: %s!\n", SDL_GetError());
        SDL_free(devices);
        return SDL_APP_FAILURE;
    } else if (!SDL_BindAudioStream(device, stream_out)) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't bind an audio stream for playback: %s!\n", SDL_GetError());
        SDL_free(devices);
        return SDL_APP_FAILURE;
    }

    SDL_Log("Opening recording device %s%s%s...\n",
            devname ? "'" : "",
            devname ? devname : "[[default]]",
            devname ? "'" : "");

    device = SDL_OpenAudioDevice(want_device, NULL);
    if (!device) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open an audio device for recording: %s!\n", SDL_GetError());
        SDL_free(devices);
        return SDL_APP_FAILURE;
    }
    SDL_free(devices);
    SDL_PauseAudioDevice(device);
    SDL_GetAudioDeviceFormat(device, &inspec, NULL);
    stream_in = SDL_CreateAudioStream(&inspec, &inspec);
    if (!stream_in) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create an audio stream for recording: %s!\n", SDL_GetError());
        return SDL_APP_FAILURE;
    } else if (!SDL_BindAudioStream(device, stream_in)) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't bind an audio stream for recording: %s!\n", SDL_GetError());
        return SDL_APP_FAILURE;
    }

    SDL_SetAudioStreamFormat(stream_in, NULL, &outspec);  /* make sure we output at the playback format. */

    SDL_Log("Ready! Hold down mouse or finger to record!\n");

    return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
{
    if (event->type == SDL_EVENT_QUIT) {
        return SDL_APP_SUCCESS;
    } else if (event->type == SDL_EVENT_KEY_DOWN) {
        if (event->key.key == SDLK_ESCAPE) {
            return SDL_APP_SUCCESS;
        }
    } else if (event->type == SDL_EVENT_MOUSE_BUTTON_DOWN) {
        if (event->button.button == 1) {
            SDL_PauseAudioStreamDevice(stream_out);
            SDL_FlushAudioStream(stream_out);  /* so no samples are held back for resampling purposes. */
            SDL_ResumeAudioStreamDevice(stream_in);
        }
    } else if (event->type == SDL_EVENT_MOUSE_BUTTON_UP) {
        if (event->button.button == 1) {
            SDL_PauseAudioStreamDevice(stream_in);
            SDL_FlushAudioStream(stream_in);  /* so no samples are held back for resampling purposes. */
            SDL_ResumeAudioStreamDevice(stream_out);
        }
    }
    return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppIterate(void *appstate)
{
    if (!SDL_AudioDevicePaused(SDL_GetAudioStreamDevice(stream_in))) {
        SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255);
    } else {
        SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
    }
    SDL_RenderClear(renderer);
    SDL_RenderPresent(renderer);

    /* Feed any new data we recorded to the output stream. It'll play when we unpause the device. */
    while (SDL_GetAudioStreamAvailable(stream_in) > 0) {
        Uint8 buf[1024];
        const int br = SDL_GetAudioStreamData(stream_in, buf, sizeof(buf));
        if (br < 0) {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to read from input audio stream: %s\n", SDL_GetError());
            return SDL_APP_FAILURE;
        } else if (!SDL_PutAudioStreamData(stream_out, buf, br)) {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to write to output audio stream: %s\n", SDL_GetError());
            return SDL_APP_FAILURE;
        }
    }

    return SDL_APP_CONTINUE;
}

void SDL_AppQuit(void *appstate, SDL_AppResult result)
{
    SDL_Log("Shutting down.\n");
    const SDL_AudioDeviceID devid_in = SDL_GetAudioStreamDevice(stream_in);
    const SDL_AudioDeviceID devid_out = SDL_GetAudioStreamDevice(stream_out);
    SDL_CloseAudioDevice(devid_in);  /* !!! FIXME: use SDL_OpenAudioDeviceStream instead so we can dump this. */
    SDL_CloseAudioDevice(devid_out);
    SDL_DestroyAudioStream(stream_in);
    SDL_DestroyAudioStream(stream_out);
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();
    SDLTest_CommonDestroyState(state);
}