2023-10-24 21:24:55 CST W43D2

examples/extract-mvs/main.go

@@ -1,5 +1,159 @@
 package main
 
-func main() {
+// http-multiclient README.txt http://localhost:8082
 
+import (
+	"fmt"
+	"os"
+	"syscall"
+	"unsafe"
+
+	ffmpeg "github.com/qrtc/ffmpeg-dev-go"
+)
+
+var (
+	videoFrameCount int
+	srcFilename     string
+)
+
+func decodePacket(videoDecCtx *ffmpeg.AVCodecContext,
+	pkt *ffmpeg.AVPacket, frame *ffmpeg.AVFrame) (ret int32) {
+
+	if ret = ffmpeg.AvCodecSendPacket(videoDecCtx, pkt); ret < 0 {
+		fmt.Fprintf(os.Stderr, "Error while sending a packet to the decoder: %s\n", ffmpeg.AvErr2str(ret))
+		return ret
+	}
+
+	for ret >= 0 {
+		ret = ffmpeg.AvCodecReceiveFrame(videoDecCtx, frame)
+		if ret == ffmpeg.AVERROR(syscall.EAGAIN) || ret == ffmpeg.AVERROR_EOF {
+			break
+		} else if ret < 0 {
+			fmt.Fprintf(os.Stderr, "Error while receiving a frame from the decoder: %s\n", ffmpeg.AvErr2str(ret))
+			return ret
+		}
+
+		if ret > 0 {
+			videoFrameCount++
+			if sd := ffmpeg.AvFrameGetSideData(frame, ffmpeg.AV_FRAME_DATA_MOTION_VECTORS); sd != nil {
+				mvs := (*ffmpeg.AVMotionVector)(unsafe.Pointer(sd.GetData()))
+				nbMvs := int(sd.GetSize()) / int(unsafe.Sizeof(*mvs))
+				for i := 0; i < nbMvs; i++ {
+					mv := ffmpeg.PointerOffset(mvs, i)
+					fmt.Fprintf(os.Stdout, "%d,%2d,%2d,%2d,%4d,%4d,%4d,%4d,0x%d\n",
+						videoFrameCount, mv.GetSource(),
+						mv.GetW(), mv.GetH(), mv.GetSrcX(), mv.GetSrcY(),
+						mv.GetDstX(), mv.GetDstY(), mv.GetFlags())
+				}
+			}
+			ffmpeg.AvFrameUnref(frame)
+		}
+	}
+
+	return 0
+}
+
+func openCodecContext(fmtCtx *ffmpeg.AVFormatContext, _type ffmpeg.AVMediaType) (
+	videoStreamIdx int32, videoStream *ffmpeg.AVStream, videoDecCtx *ffmpeg.AVCodecContext, ret int32) {
+	var (
+		dec *ffmpeg.AVCodec
+		opt *ffmpeg.AVDictionary
+	)
+	ret = ffmpeg.AvFindBestStream(fmtCtx, _type, -1, -1, &dec, 0)
+	if ret < 0 {
+		fmt.Fprintf(os.Stderr, "Could not find %s stream in input file '%s'\n",
+			ffmpeg.AvGetMediaTypeString(_type), srcFilename)
+		return 0, nil, nil, ret
+	} else {
+		videoStreamIdx = ret
+		videoStream = fmtCtx.GetStreams()[videoStreamIdx]
+
+		if videoDecCtx = ffmpeg.AvCodecAllocContext3(dec); videoDecCtx == nil {
+			fmt.Fprintf(os.Stderr, "Failed to allocate codec\n")
+			return 0, nil, nil, ffmpeg.AVERROR(syscall.EINVAL)
+		}
+
+		if ret = ffmpeg.AvCodecParametersToContext(videoDecCtx, videoStream.GetCodecpar()); ret < 0 {
+			fmt.Fprintf(os.Stderr, "Failed to copy codec parameters to codec context\n")
+			return 0, nil, nil, ret
+		}
+
+		// Init the video decoder
+		ffmpeg.AvDictSet(&opt, "flags2", "+export_mvs", 0)
+		if ret = ffmpeg.AvCodecOpen2(videoDecCtx, dec, &opt); ret < 0 {
+			fmt.Fprintf(os.Stderr, "Failed to open %s codec\n", ffmpeg.AvGetMediaTypeString(_type))
+			return 0, nil, nil, ret
+		}
+
+	}
+	return videoStreamIdx, videoStream, videoDecCtx, 0
+}
+
+func main() {
+	var (
+		fmtCtx         *ffmpeg.AVFormatContext
+		videoDecCtx    *ffmpeg.AVCodecContext
+		videoStream    *ffmpeg.AVStream
+		videoStreamIdx int32
+		frame          *ffmpeg.AVFrame
+
+		pkt ffmpeg.AVPacket
+		ret int32
+	)
+
+	if len(os.Args) != 2 {
+		fmt.Fprintf(os.Stderr, "Usage: %s <video>\n", os.Args[0])
+		os.Exit(1)
+	}
+	srcFilename = os.Args[1]
+
+	if ret = ffmpeg.AvFormatOpenInput(&fmtCtx, srcFilename, nil, nil); ret < 0 {
+		fmt.Fprintf(os.Stderr, "Could not open source file %s\n", srcFilename)
+		os.Exit(1)
+	}
+
+	if ret = ffmpeg.AvFormatFindStreamInfo(fmtCtx, nil); ret < 0 {
+		fmt.Fprintf(os.Stderr, "Could not find stream information\n")
+		os.Exit(1)
+	}
+
+	videoStreamIdx, videoStream, videoDecCtx, ret = openCodecContext(fmtCtx, ffmpeg.AVMEDIA_TYPE_VIDEO)
+
+	ffmpeg.AvDumpFormat(fmtCtx, 0, srcFilename, 0)
+
+	if videoStream == nil {
+		fmt.Fprintf(os.Stderr, "Could not find video stream in the input, aborting\n")
+		ret = 1
+		goto end
+	}
+
+	if frame = ffmpeg.AvFrameAlloc(); frame == nil {
+		fmt.Fprintf(os.Stderr, "Could not allocate frame\n")
+		ret = ffmpeg.AVERROR(syscall.ENOMEM)
+		goto end
+	}
+
+	fmt.Fprintf(os.Stdout, "framenum,source,blockw,blockh,srcx,srcy,dstx,dsty,flags\n")
+
+	// read frames from the file
+	for ffmpeg.AvReadFrame(fmtCtx, &pkt) >= 0 {
+		if pkt.GetStreamIndex() == videoStreamIdx {
+			ret = decodePacket(videoDecCtx, &pkt, frame)
+		}
+		ffmpeg.AvPacketUnref(&pkt)
+		if ret < 0 {
+			break
+		}
+	}
+
+	// flush cached frames
+	decodePacket(videoDecCtx, nil, frame)
+
+end:
+	ffmpeg.AvCodecFreeContext(&videoDecCtx)
+	ffmpeg.AvFormatCloseInput(&fmtCtx)
+	ffmpeg.AvFrameFree(&frame)
+	if ret < 0 {
+		os.Exit(1)
+	}
 }