使用Golang和FFmpeg实现视频剪辑的方法

package main

import (
    "fmt"
    "os"
    "strings"
    "sync"
    "time"

    "github.com/giorgisio/goav/avcodec"
    "github.com/giorgisio/goav/avformat"
)

func main() {
    start := time.Now()

    inputFileName := "input.mp4"
    outputFileName := "output.mp4"
    startTime := 10
    duration := 20

    // 初始化FFmpeg库
    avformat.AvRegisterAll()
    avcodec.AvcodecRegisterAll()

    // 打开输入文件
    inputFormatContext := avformat.AvformatAllocContext()
    if avformat.AvformatOpenInput(&inputFormatContext, inputFileName, nil, nil) != 0 {
        fmt.Println("Failed to open input file")
        os.Exit(1)
    }

    // 找到输入文件中的流信息
    if avformat.AvformatFindStreamInfo(inputFormatContext, nil) < 0 {
        fmt.Println("Failed to find stream info")
        os.Exit(1)
    }

    // 寻找视频流信息
    var videoStreamIndex int
    for i := 0; i < int(inputFormatContext.NbStreams()); i++ {
        if inputFormatContext.Streams()[i].CodecParameters().CodecType() == avformat.AVMEDIA_TYPE_VIDEO {
            videoStreamIndex = i
            break
        }
    }

    // 获取视频流的解码器上下文
    videoCodecContext := inputFormatContext.Streams()[videoStreamIndex].Codec()

    // 初始化解码器
    videoCodec := avcodec.AvcodecFindDecoder(videoCodecContext.CodecId())
    if videoCodec == nil {
        fmt.Println("Unsupported codec")
        os.Exit(1)
    }

    videoCodecContext.AvcodecOpen2(videoCodec, nil)

    // 创建输出文件
    outputFormatContext := avformat.AvformatAllocContext()
    if avformat.AvformatAllocOutputContext2(&outputFormatContext, nil, "", outputFileName) != 0 {
        fmt.Println("Failed to create output file")
        os.Exit(1)
    }

    // 添加视频流到输出文件
    outputVideoStream := outputFormatContext.AvformatNewStream(nil)
    if outputVideoStream == nil {
        fmt.Println("Failed to create output video stream")
        os.Exit(1)
    }

    // 复制输入视频流的参数到输出视频流
    outputVideoStream.SetCodecParameters(videoCodecContext.CodecParameters())

    // 写入输出文件头
    if avformat.AvformatWriteHeader(outputFormatContext, nil) != 0 {
        fmt.Println("Failed to write output file header")
        os.Exit(1)
    }

    // 读取和写入视频帧
    packets := avformat.AvPacketAlloc()
    frame := avutil.AvFrameAlloc()
    frameCount := 0
    for {
        // 从输入文件中读取一个packet
        if avformat.AvReadFrame(inputFormatContext, packets) < 0 {
            break
        }

        // 判断是否为视频流的packet
        if packets.StreamIndex() == videoStreamIndex {
            // 解码packet
            if avcodec.AvcodecSendPacket(videoCodecContext, packets) != 0 {
                fmt.Println("Failed to send packet to decoder")
                os.Exit(1)
            }

            for avcodec.AvcodecReceiveFrame(videoCodecContext, frame) == 0 {
                // 判断当前帧是否在指定的时间范围内
                currentTime := float64(frameCount) * avutil.AvQ2D(videoFormatContext.Streams()[videoStreamIndex].TimeBase())
                if currentTime >= float64(startTime) && currentTime <= float64(startTime+duration) {
                // 将剪辑好的帧写入输出文件
                if avcodec.AvcodecSendFrame(outputCodecContext, frame) != 0 {
                    fmt.Println("Failed to send framed to encoder")
                    os.Exit(1)
                }

                for {
                    if avcodec.AvcodecReceivePacket(outputCodecContext, packets) != 0 {
                        break
                    }

                    // 将packet写入输出文件
                    avformat.AvWriteFrame(outputFormatContext, packets)
                    avcodec.AvPacketUnref(packets)
                }
            }

            frameCount++
        }
    }

    // 写入输出文件尾部
    avformat.AvWriteTrailer(outputFormatContext)

    // 释放资源
    avutil.AvFrameFree(frame)
    avformat.AvformatCloseInput(&inputFormatContext)
    avformat.AvformatFreeContext(inputFormatContext)
    avformat.AvformatFreeContext(outputFormatContext)
    avcodec.AvcodecClose(videoCodecContext)
    avcodec.AvcodecFreeContext(videoCodecContext)

    fmt.Println("Video clipping completed in", time.Since(start))
}