    // The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
    /*

        This is an example illustrating the use of the ffmpeg wrappers.
        It attempts to read audio from a microphone if available, and saves the audio to wav.
    */

    #include <iostream>
    #include <chrono>
    #include <dlib/media.h>
    #include <dlib/cmd_line_parser.h>

    using namespace std;
    using namespace std::chrono;
    using namespace std::chrono_literals;
    using namespace dlib;
    using namespace dlib::ffmpeg;

    int main(const int argc, const char** argv)
    try
    {
        command_line_parser parser;
        parser.add_option("t",      "capture time in seconds", 1);
        parser.add_option("i",      "input microphone device. E.g. hw:0,0", 1);
        parser.add_option("o",      "output audio file. E.g. recording.m4a, recording.wav. Default: recording.m4a", 1);
        parser.add_option("codec",  "audio codec. E.g. `aac`, `pcm_s16le`. Recommend `pcm_s16le` for WAV files and `aac` for `M4A` files. Default: `aac`", 1);

        parser.set_group_name("Help Options");
        parser.add_option("h",      "alias of --help");
        parser.add_option("help",   "display this message and exit");

        parser.parse(argc, argv);
        const char* one_time_opts[] = {"t", "i", "o", "codec"};
        parser.check_one_time_options(one_time_opts);

        if (parser.option("h") || parser.option("help"))
        {
            parser.print_options();
            return 0;
        }

        const seconds time{get_option(parser, "t",  1)};
        const std::string device    = get_option(parser, "i",       "hw:0,0");
        const std::string filename  = get_option(parser, "o",       "recording.m4a");
        const std::string codec     = get_option(parser, "codec",   "aac");

        // Open microphone
        demuxer cap([&] {
            demuxer::args args;
            args.filepath       = device;
            args.input_format   = "alsa";
            return args;
        }());

        if (!cap.is_open())
        {
            cout << "Failed to open device: " << device << '\n';
            return EXIT_FAILURE;
        }

        // Create WAV file
        muxer writer([&] {
            muxer::args args;
            args.filepath                   = filename;
            args.enable_image               = false;
            args.args_audio.codec_name      = codec;
            args.args_audio.sample_rate     = cap.sample_rate();
            args.args_audio.channel_layout  = cap.channel_layout();
            args.args_audio.fmt             = cap.sample_fmt();
            return args;
        }());

        if (!writer.is_open())
        {
            cout << "Failed to open wav file" << endl;
            return EXIT_FAILURE;
        }

        // Pull and push
        const auto start = high_resolution_clock::now();
        frame f;
        while (cap.read(f) && (high_resolution_clock::now() - start) < time)
            writer.push(std::move(f));

        return EXIT_SUCCESS;
    }
    catch (const std::exception& e)
    {
        printf("%s\n", e.what());
        return EXIT_FAILURE;
    }