go + ffmpeg + goav 实现拉流解码器

go get github.com/giorgisio/goav

	// 加载ffmpeg的网络库	avformat.AvRegisterAll()	// 加载ffmpeg的编解码库	avcodec.AvcodecRegisterAll()	log.Printf("AvFilter Version:\t%v", avfilter.AvfilterVersion())	log.Printf("AvDevice Version:\t%v", avdevice.AvdeviceVersion())	log.Printf("SWScale Version:\t%v", swscale.SwscaleVersion())	log.Printf("AvUtil Version:\t%v", avutil.AvutilVersion())	log.Printf("AvCodec Version:\t%v", avcodec.AvcodecVersion())	log.Printf("Resample Version:\t%v", swresample.SwresampleLicense())

/**打开视频流 */func openInput(filename string) *avformat.Context {	//	formatCtx := avformat.AvformatAllocContext()	// 打开视频流	if avformat.AvformatOpenInput(&formatCtx, filename, nil, nil) != 0 {		fmt.Printf("Unable to open file %s\n", filename)		return nil;	}	return formatCtx; }

/**检索流信息 */func findStreamInfo(ctx *avformat.Context) bool {	if ctx.AvformatFindStreamInfo(nil) < 0 {		log.Println("Error: Couldn't find stream information.")		// 关闭文件，释放 媒体文件/流的上下文		ctx.AvformatCloseInput()		return false	}	return true}

 /**获取第一帧视频位置 */func findFirstVideoStreamIndex(ctx *avformat.Context) int {	videoStreamIndex := -1;	for index, stream := range ctx.Streams() {		switch stream.CodecParameters().AvCodecGetType() {		case avformat.AVMEDIA_TYPE_VIDEO:			return index		}	}	return videoStreamIndex;} /**读取一帧视频帧*/func findFirstVideoStreamCodecContext(ctx *avformat.Context) *avformat.CodecContext {	for _, stream := range ctx.Streams() {		switch stream.CodecParameters().AvCodecGetType() {		case avformat.AVMEDIA_TYPE_VIDEO:			return stream.Codec()		}	}	return nil} /**根据索引获取视频帧 */func findVideoStreamCodecContext(ctx *avformat.Context ,videoStreamIndex int) *avformat.CodecContext {	if videoStreamIndex >= 0 {		streams := ctx.Streams()		stream := streams[videoStreamIndex]		return stream.Codec();	}	return nil}

/**查找并打开编解码器 */func findAndOpenCodec(codecCtx *avformat.CodecContext) *avcodec.Context {	codec := avcodec.AvcodecFindDecoder(avcodec.CodecId(codecCtx.GetCodecId()))	if codec == nil {		fmt.Println("Unsupported codec!")		return nil	}	codecContext := codec.AvcodecAllocContext3()	if codecContext.AvcodecCopyContext((*avcodec.Context)(unsafe.Pointer(codecCtx))) != 0 {		fmt.Println("Couldn't copy codec context")		return nil	}	if codecContext.AvcodecOpen2(codec, nil) < 0 {		fmt.Println("Could not open codec")		return nil	}	return codecContext}

for i := 0; i < int(formatCtx.NbStreams()); i++ {		switch formatCtx.Streams()[i].CodecParameters().AvCodecGetType() {		case avformat.AVMEDIA_TYPE_VIDEO:			// 循环读取视频帧并解码成 rgb , 默认就是yuv数据			packet := avcodec.AvPacketAlloc()			frameNumber := 1			for formatCtx.AvReadFrame(packet) >= 0 {				// Is this a packet from the video stream?				if packet.StreamIndex() == i {					// Is this a packet from the video stream?					// Decode video frame					response := codecCtx.AvcodecSendPacket(packet)					if response < 0 {						fmt.Printf("Error while sending a packet to the decoder: %s\n", avutil.ErrorFromCode(response))					}					for response >= 0 {						response = codecCtx.AvcodecReceiveFrame((*avcodec.Frame)(unsafe.Pointer(pFrame)))						if response == avutil.AvErrorEAGAIN || response == avutil.AvErrorEOF {							break						} else if response < 0 {							fmt.Printf("Error while receiving a frame from the decoder: %s\n", avutil.ErrorFromCode(response))							return						}						// 从原生数据转换成RGB， 转换 5 个视频帧						// Convert the image from its native format to RGB						if frameNumber <= 5 {							swscale.SwsScale2(swsCtx, avutil.Data(pFrame),								avutil.Linesize(pFrame), 0, codecCtx.Height(),								avutil.Data(pFrameRGB), avutil.Linesize(pFrameRGB)) 							// 保存到本地硬盘							fmt.Printf("Writing frame %d\n", frameNumber)							SaveFrame(pFrameRGB, codecCtx.Width(), codecCtx.Height(), frameNumber)						} else {							return						}						frameNumber++					}					// 释放资源					// Free the packet that was allocated by av_read_frame					packet.AvFreePacket()				}			} 			// Free the RGB image			avutil.AvFree(buffer)			avutil.AvFrameFree(pFrameRGB) 			// Free the YUV frame			avutil.AvFrameFree(pFrame) 			// Close the codecs			codecCtx.AvcodecClose()			(*avcodec.Context)(unsafe.Pointer(avCodecCtx)).AvcodecClose() 			// Close the video file			formatCtx.AvformatCloseInput()		default:			fmt.Println("Didn't find a video stream")		}	}

package main import (	"fmt"	"github.com/giorgisio/goav/avcodec"	"github.com/giorgisio/goav/avdevice"	"github.com/giorgisio/goav/avfilter"	"github.com/giorgisio/goav/avformat"	"github.com/giorgisio/goav/avutil"	"github.com/giorgisio/goav/swresample"	"github.com/giorgisio/goav/swscale"	"log"	"os"	"unsafe") // SaveFrame writes a single frame to disk as a PPM filefunc SaveFrame(frame *avutil.Frame, width, height, frameNumber int) {	// Open file	fileName := fmt.Sprintf("frame%d.ppm", frameNumber)	file, err := os.Create(fileName)	if err != nil {		log.Println("Error Reading")	}	defer file.Close() 	// Write header	header := fmt.Sprintf("P6\n%d %d\n255\n", width, height)	file.Write([]byte(header)) 	// Write pixel data	for y := 0; y < height; y++ {		data0 := avutil.Data(frame)[0]		buf := make([]byte, width*3)		startPos := uintptr(unsafe.Pointer(data0)) + uintptr(y)*uintptr(avutil.Linesize(frame)[0])		for i := 0; i < width*3; i++ {			element := *(*uint8)(unsafe.Pointer(startPos + uintptr(i)))			buf[i] = element		}		file.Write(buf)	}} func main() { 	filename := "/home/yinyue/upload/sucai.mp4"	// output := "";	// 加载ffmpeg的网络库	avformat.AvRegisterAll()	// 加载ffmpeg的编解码库	avcodec.AvcodecRegisterAll()	log.Printf("AvFilter Version:\t%v", avfilter.AvfilterVersion())	log.Printf("AvDevice Version:\t%v", avdevice.AvdeviceVersion())	log.Printf("SWScale Version:\t%v", swscale.SwscaleVersion())	log.Printf("AvUtil Version:\t%v", avutil.AvutilVersion())	log.Printf("AvCodec Version:\t%v", avcodec.AvcodecVersion())	log.Printf("Resample Version:\t%v", swresample.SwresampleLicense()) 	// 打开视频流	formatCtx := openInput(filename)	if formatCtx == nil {		return	}	// 检索流信息	success := findStreamInfo(formatCtx);	if !success {		return	}	fmt.Println("检索流信息： " , success)	// 打印 ffmpeg 的日志	formatCtx.AvDumpFormat(0, filename, 0)	// 读取一帧视频帧	avCodecCtx := findFirstVideoStreamCodecContext(formatCtx)	if avCodecCtx == nil {		fmt.Println("没有发现视频帧： ")		return	}	// 查找并打开解码器	codecCtx := findAndOpenCodec(avCodecCtx)	if codecCtx == nil {		fmt.Println("没有发现解码器，或解码器不可用： ")		return	} 	// Allocate video frame	pFrame := avutil.AvFrameAlloc() 	// Allocate an AVFrame structure	pFrameRGB := avutil.AvFrameAlloc() 	// Determine required buffer size and allocate buffer	numBytes := uintptr(avcodec.AvpictureGetSize(avcodec.AV_PIX_FMT_RGB24, codecCtx.Width(), codecCtx.Height()))	buffer := avutil.AvMalloc(numBytes) 	// Assign appropriate parts of buffer to image planes in pFrameRGB	// Note that pFrameRGB is an AVFrame, but AVFrame is a superset	// of AVPicture	avp := (*avcodec.Picture)(unsafe.Pointer(pFrameRGB))	avp.AvpictureFill((*uint8)(buffer), avcodec.AV_PIX_FMT_RGB24, codecCtx.Width(), codecCtx.Height()) 	// initialize SWS context for software scaling	swsCtx := swscale.SwsGetcontext(		codecCtx.Width(),		codecCtx.Height(),		(swscale.PixelFormat)(codecCtx.PixFmt()),		codecCtx.Width(),		codecCtx.Height(),		avcodec.AV_PIX_FMT_RGB24,		avcodec.SWS_BILINEAR,		nil,		nil,		nil,	) 	for i := 0; i < int(formatCtx.NbStreams()); i++ {		switch formatCtx.Streams()[i].CodecParameters().AvCodecGetType() {		case avformat.AVMEDIA_TYPE_VIDEO:			// 循环读取视频帧并解码成 rgb , 默认就是yuv数据			packet := avcodec.AvPacketAlloc()			frameNumber := 1			for formatCtx.AvReadFrame(packet) >= 0 {				// Is this a packet from the video stream?				if packet.StreamIndex() == i {					// Is this a packet from the video stream?					// Decode video frame					response := codecCtx.AvcodecSendPacket(packet)					if response < 0 {						fmt.Printf("Error while sending a packet to the decoder: %s\n", avutil.ErrorFromCode(response))					}					for response >= 0 {						response = codecCtx.AvcodecReceiveFrame((*avcodec.Frame)(unsafe.Pointer(pFrame)))						if response == avutil.AvErrorEAGAIN || response == avutil.AvErrorEOF {							break						} else if response < 0 {							fmt.Printf("Error while receiving a frame from the decoder: %s\n", avutil.ErrorFromCode(response))							return						}						// 从原生数据转换成RGB， 转换 5 个视频帧						// Convert the image from its native format to RGB						if frameNumber <= 5 {							swscale.SwsScale2(swsCtx, avutil.Data(pFrame),								avutil.Linesize(pFrame), 0, codecCtx.Height(),								avutil.Data(pFrameRGB), avutil.Linesize(pFrameRGB)) 							// 保存到本地硬盘							fmt.Printf("Writing frame %d\n", frameNumber)							SaveFrame(pFrameRGB, codecCtx.Width(), codecCtx.Height(), frameNumber)						} else {							return						}						frameNumber++					}					// 释放资源					// Free the packet that was allocated by av_read_frame					packet.AvFreePacket()				}			} 			// Free the RGB image			avutil.AvFree(buffer)			avutil.AvFrameFree(pFrameRGB) 			// Free the YUV frame			avutil.AvFrameFree(pFrame) 			// Close the codecs			codecCtx.AvcodecClose()			(*avcodec.Context)(unsafe.Pointer(avCodecCtx)).AvcodecClose() 			// Close the video file			formatCtx.AvformatCloseInput()		default:			fmt.Println("Didn't find a video stream")		}	} } /**打开视频流 */func openInput(filename string) *avformat.Context {	//	formatCtx := avformat.AvformatAllocContext()	// 打开视频流	if avformat.AvformatOpenInput(&formatCtx, filename, nil, nil) != 0 {		fmt.Printf("Unable to open file %s\n", filename)		return nil;	}	return formatCtx; } /**检索流信息 */func findStreamInfo(ctx *avformat.Context) bool {	if ctx.AvformatFindStreamInfo(nil) < 0 {		log.Println("Error: Couldn't find stream information.")		// 关闭文件，释放 媒体文件/流的上下文		ctx.AvformatCloseInput()		return false	}	return true}  /**获取第一帧视频位置 */func findFirstVideoStreamIndex(ctx *avformat.Context) int {	videoStreamIndex := -1;	for index, stream := range ctx.Streams() {		switch stream.CodecParameters().AvCodecGetType() {		case avformat.AVMEDIA_TYPE_VIDEO:			return index		}	}	return videoStreamIndex;} /**读取一帧视频帧*/func findFirstVideoStreamCodecContext(ctx *avformat.Context) *avformat.CodecContext {	for _, stream := range ctx.Streams() {		switch stream.CodecParameters().AvCodecGetType() {		case avformat.AVMEDIA_TYPE_VIDEO:			return stream.Codec()		}	}	return nil} /**根据索引获取视频帧 */func findVideoStreamCodecContext(ctx *avformat.Context ,videoStreamIndex int) *avformat.CodecContext {	if videoStreamIndex >= 0 {		streams := ctx.Streams()		stream := streams[videoStreamIndex]		return stream.Codec();	}	return nil} /**查找并打开编解码器 */func findAndOpenCodec(codecCtx *avformat.CodecContext) *avcodec.Context {	codec := avcodec.AvcodecFindDecoder(avcodec.CodecId(codecCtx.GetCodecId()))	if codec == nil {		fmt.Println("Unsupported codec!")		return nil	}	codecContext := codec.AvcodecAllocContext3()	if codecContext.AvcodecCopyContext((*avcodec.Context)(unsafe.Pointer(codecCtx))) != 0 {		fmt.Println("Couldn't copy codec context")		return nil	}	if codecContext.AvcodecOpen2(codec, nil) < 0 {		fmt.Println("Could not open codec")		return nil	}	return codecContext}