linux C 音乐播放

Linux C 音乐播放可以通过调用 ALSA API 来实现。 ALSA (Advanced Linux Sound Architecture) 是一个为 Linux 提供音频支持的框架，它提供了一组开发者接口，使应用程序可以在 Linux 上播放音频。

在 C 语言中，可以通过 ALSA API 来实现音频播放。具体来说，你需要创建一个 PCM (脉冲编码调制) 设备，然后使用 PCM 接口来读取音频数据并将其写入 PCM 设备。要播放音频，你需要打开音频文件、解码音频数据并将其写入 PCM 设备。你还需要设置 PCM 设备的属性，如采样率、声道数、采样格式等。

下面是一个简单的示例代码，它使用 ALSA API 在 Linux 上播放音频：

#include <stdio.h>
#include <stdlib.h>
#include <alsa/asoundlib.h>

#define SAMPLE_RATE 44100
#define NUM_CHANNELS 2
#define SAMPLE_SIZE 16
#define BUFFER_SIZE 4096

int main(int argc, char *argv[])
{
    char *filename = argv;
    FILE *file = fopen(filename, "r");
    if (!file) {
        printf("Failed to open file: %s\n", filename);
        return 1;
    }

    // Initialize ALSA
    snd_pcm_t *pcm_handle;
    snd_pcm_hw_params_t *hw_params;
    int err;
    err = snd_pcm_open(&pcm_handle, "default", SND_PCM_STREAM_PLAYBACK, 0);
    if (err < 0) {
        printf("Failed to open PCM device: %s\n", snd_strerror(err));
        return 1;
    }
    err = snd_pcm_hw_params_malloc(&hw_params);
    if (err < 0) {
        printf("Failed to allocate HW params: %s\n", snd_strerror(err));
        return 1;
    }
    err = snd_pcm_hw_params_any(pcm_handle, hw_params);
    if (err < 0) {
        printf("Failed to initialize HW params: %s\n", snd_strerror(err));
        return 1;
    }
    err = snd_pcm_hw_params_set_access(pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
    if (err < 0) {
        printf("Failed to set access type: %s\n", snd_strerror(err));
        return 1;
    }
    err = snd_pcm_hw_params_set_format(pcm_handle, hw_params, SND_PCM_FORMAT_S16_LE);
    if (err < 0) {
        printf("Failed to set sample format: %s\n", snd_strerror(err));
        return 1;
    }
    unsigned int sample_rate = SAMPLE_RATE;
    err = snd_pcm_hw_params_set_rate_near(pcm_handle, hw_params, &sample_rate, 0);
    if (err < 0) {
        printf("Failed to set sample rate: %s\n", snd_strerror(err));
        return 1;
    }
    err = snd_pcm_hw_params_set_channels(pcm_handle, hw_params, NUM_CHANNELS);
    if (err < 0) {
        printf("Failed to set channel count: %s\n", snd_strerror(err));
        return 1;
    }
    err = snd_pcm_hw_params(pcm_handle, hw_params);
    if (err < 0) {
        printf("Failed to set HW params: %s\n", snd_strerror(err));
        return 1;
    }
    snd_pcm_hw_params_free(hw_params);

    // Read and play audio data
    char buffer[BUFFER_SIZE];
    while (!feof(file)) {
        size_t num_bytes = fread(buffer, 1, BUFFER_SIZE, file);
        if (num_bytes == 0) {
            break;
        }
        int num_frames = num_bytes / (NUM_CHANNELS * (SAMPLE_SIZE / 8));
        int num_frames_written = snd_pcm_writei(pcm_handle, buffer, num_frames);
        if (num_frames_written < num_frames) {
            printf("Write error: %s\n", snd_strerror(num_frames_written));
            break;
        }
    }

    // Close the PCM device and file
    snd_pcm_drain(pcm_handle);
    snd_pcm_close(pcm_handle);
    fclose(file);

    return 0;
}