# FFmpeg下載地址（Windows）
https://www.gyan.dev/ffmpeg/builds/
# 解壓后記得把`bin`目錄加到系統(tǒng)環(huán)境變量Path里！

// 示例：創(chuàng)建控制臺(tái)項(xiàng)目
dotnet new console -n AudioExtractor
cd AudioExtractor

using System;
using System.Diagnostics;

class Program
{
    static void Main(string[] args)
    {
        string videoPath = "input.mp4";  // 輸入視頻文件
        string audioPath = "output.mp3"; // 輸出音頻文件

        // 創(chuàng)建FFmpeg進(jìn)程
        ProcessStartInfo startInfo = new ProcessStartInfo
        {
            FileName = "ffmpeg.exe", // 這里寫FFmpeg的完整路徑更好！
            Arguments = $"-i {videoPath} -vn -acodec libmp3lame -ar 44100 -ac 2 -ab 192k {audioPath}",
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false, // 必須設(shè)為false才能捕獲輸出
            CreateNoWindow = true    // 不顯示黑窗口
        };

        using (Process process = Process.Start(startInfo))
        {
            string output = process.StandardOutput.ReadToEnd();
            string error = process.StandardError.ReadToEnd();

            process.WaitForExit();

            Console.WriteLine("輸出信息: " + output);
            Console.WriteLine("錯(cuò)誤信息: " + error);

            if (process.ExitCode == 0)
            {
                Console.WriteLine("音頻提取成功！");
            }
            else
            {
                Console.WriteLine("提取失敗，請(qǐng)檢查輸入文件是否存在或FFmpeg路徑是否正確！");
            }
        }
    }
}

# 安裝FFmpeg.AutoGen（C#的FFmpeg封裝庫）
dotnet add package FFmpeg.AutoGen

using FFmpeg.AutoGen;

class Program
{
    [STAThread]
    static void Main(string[] args)
    {
        ffmpeg.RootPath = @"C:\ffmpeg\bin"; // 設(shè)置FFmpeg路徑

        // 初始化FFmpeg
        ffmpeg.avformat_network_init();

        // 打開輸入文件
        AVFormatContext* formatContext = null;
        if (ffmpeg.avformat_open_input(&formatContext, "input.mp4", null, null) != 0)
        {
            Console.WriteLine("無法打開視頻文件！");
            return;
        }

        // 查找音頻流
        if (ffmpeg.avformat_find_stream_info(formatContext, null) < 0)
        {
            Console.WriteLine("無法找到音頻流！");
            return;
        }

        int audioStreamIndex = -1;
        for (int i = 0; i < formatContext->nb_streams; i++)
        {
            if (formatContext->streams[i]->codecpar->codec_type == AVMediaType.AVMEDIA_TYPE_AUDIO)
            {
                audioStreamIndex = i;
                break;
            }
        }

        if (audioStreamIndex < 0)
        {
            Console.WriteLine("未找到音頻流！");
            return;
        }

        // 獲取音頻編解碼器
        AVCodecParameters* codecParameters = formatContext->streams[audioStreamIndex]->codecpar;
        AVCodec* codec = ffmpeg.avcodec_find_decoder(codecParameters->codec_id);
        AVCodecContext* codecContext = ffmpeg.avcodec_alloc_context3(codec);

        if (ffmpeg.avcodec_parameters_to_context(codecContext, codecParameters) < 0)
        {
            Console.WriteLine("無法復(fù)制編解碼器參數(shù)！");
            return;
        }

        if (ffmpeg.avcodec_open2(codecContext, codec, null) < 0)
        {
            Console.WriteLine("無法打開編解碼器！");
            return;
        }

        // 讀取并保存音頻數(shù)據(jù)
        AVPacket* packet = ffmpeg.av_packet_alloc();
        AVFrame* frame = ffmpeg.av_frame_alloc();

        while (ffmpeg.av_read_frame(formatContext, packet) >= 0)
        {
            if (packet->stream_index == audioStreamIndex)
            {
                // 解碼音頻幀
                if (ffmpeg.avcodec_send_packet(codecContext, packet) == 0)
                {
                    while (ffmpeg.avcodec_receive_frame(codecContext, frame) == 0)
                    {
                        // 這里可以處理音頻幀數(shù)據(jù)（比如寫入文件）
                        // 為了簡單起見，這里只打印幀信息
                        Console.WriteLine($"解碼音頻幀: {frame->pts}");
                    }
                }
            }
            ffmpeg.av_packet_unref(packet);
        }

        // 釋放資源
        ffmpeg.av_frame_free(&frame);
        ffmpeg.av_packet_free(&packet);
        ffmpeg.avcodec_free_context(&codecContext);
        ffmpeg.avformat_close_input(&formatContext);
    }
}

// 使用WPF創(chuàng)建GUI界面（示例代碼簡化版）
using System.Windows;
using System.Diagnostics;

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private void ExtractAudioButton_Click(object sender, RoutedEventArgs e)
    {
        string videoPath = VideoPathTextBox.Text;
        string audioPath = AudioPathTextBox.Text;

        ProcessStartInfo startInfo = new ProcessStartInfo
        {
            FileName = "ffmpeg.exe",
            Arguments = $"-i {videoPath} -vn -acodec copy {audioPath}",
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
            CreateNoWindow = true
        };

        using (Process process = Process.Start(startInfo))
        {
            process.WaitForExit();
            StatusTextBlock.Text = "音頻提取完成！";
        }
    }
}

// 示例：批量處理當(dāng)前目錄下所有視頻
string[] videoFiles = Directory.GetFiles(Directory.GetCurrentDirectory(), "*.mp4");

foreach (string video in videoFiles)
{
    string audio = Path.ChangeExtension(video, ".mp3");
    Process.Start("ffmpeg.exe", $"-i {video} -vn -acodec libmp3lame {audio}");
}

try
{
    // 調(diào)用FFmpeg代碼
}
catch (Exception ex)
{
    Console.WriteLine($"程序出錯(cuò)啦！錯(cuò)誤信息：{ex.Message}");
}