2023-03-10：YUV420P像素数据编码为JPEG图片，请用go语言实现。
答案2023-03-10：
方法一、使用 github.com/moonfdd/ffmpeg-go 库,基于雷霄骅的代码修改。
方法二、使用golang官方库image/jpeg，yuv420p先转换成rgb，再转换成jpeg。代码是用山寨版的chatgpt生成。
代码语言：shell复制go run ./examples/leixiaohua1020/simplest_ffmpeg_picture_encoder/main.go方法一，参考了雷霄骅的图像编码器，代码用golang编写。代码如下：
代码语言：go复制// https://github.com/leixiaohua1020/simplest_ffmpeg_picture_encoder/blob/master/simplest_ffmpeg_picture_encoder/simplest_ffmpeg_picture_encoder.cpp
package main
import (
"fmt"
"os"
"os/exec"
"unsafe"
"github.com/moonfdd/ffmpeg-go/ffcommon"
"github.com/moonfdd/ffmpeg-go/libavcodec"
"github.com/moonfdd/ffmpeg-go/libavformat"
"github.com/moonfdd/ffmpeg-go/libavutil"
)
func main0() (ret ffcommon.FInt) {
var pFormatCtx *libavformat.AVFormatContext
var fmt0 *libavformat.AVOutputFormat
var video_st *libavformat.AVStream
var pCodecCtx *libavcodec.AVCodecContext
var pCodec *libavcodec.AVCodec
var picture_buf *ffcommon.FUint8T
var picture *libavutil.AVFrame
var pkt libavcodec.AVPacket
var y_size ffcommon.FInt
var got_picture ffcommon.FInt = 0
var size ffcommon.FInt
var in_file *os.File //YUV source
var in_w, in_h ffcommon.FInt = 640, 360 //YUV's width and height
var out_file = "./out/pic.jpg" //Output file
in := "./out/pic.yuv"
//是否存在yuv文件
_, err := os.Stat(in)
if err != nil {
if os.IsNotExist(err) {
fmt.Println("create yuv file")
exec.Command("./lib/ffmpeg", "-i", "./resources/big_buck_bunny.mp4", "-pix_fmt", "yuv420p", in, "-y").CombinedOutput()
}
}
in_file, _ = os.Open(in)
if in_file == nil {
return -1
}
libavformat.AvRegisterAll()
//Method 1
pFormatCtx = libavformat.AvformatAllocContext()
//Guess format
fmt0 = libavformat.AvGuessFormat("mjpeg", "", "")
pFormatCtx.Oformat = fmt0
//Output URL
if libavformat.AvioOpen(&pFormatCtx.Pb, out_file, libavformat.AVIO_FLAG_READ_WRITE) < 0 {
fmt.Printf("Couldn't open output file.")
return -1
}
//Method 2. More simple
//avformat_alloc_output_context2(&pFormatCtx, NULL, NULL, out_file);
//fmt = pFormatCtx->oformat;
video_st = pFormatCtx.AvformatNewStream(nil)
if video_st == nil {
return -1
}
pCodecCtx = video_st.Codec
pCodecCtx.CodecId = fmt0.VideoCodec
pCodecCtx.CodecType = libavutil.AVMEDIA_TYPE_VIDEO
pCodecCtx.PixFmt = libavutil.AV_PIX_FMT_YUVJ420P
pCodecCtx.Width = in_w
pCodecCtx.Height = in_h
pCodecCtx.TimeBase.Num = 1
pCodecCtx.TimeBase.Den = 25
//Output some information
pFormatCtx.AvDumpFormat(0, out_file, 1)
pCodec = libavcodec.AvcodecFindEncoder(pCodecCtx.CodecId)
if pCodec == nil {
fmt.Printf("Codec not found.")
return -1
}
if pCodecCtx.AvcodecOpen2(pCodec, nil) < 0 {
fmt.Printf("Could not open codec.")
return -1
}
picture = libavutil.AvFrameAlloc()
picture.Width = pCodecCtx.Width
picture.Height = pCodecCtx.Height
picture.Format = pCodecCtx.PixFmt
size = libavcodec.AvpictureGetSize(pCodecCtx.PixFmt, pCodecCtx.Width, pCodecCtx.Height)
picture_buf = (*byte)(unsafe.Pointer(libavutil.AvMalloc(uint64(size))))
if picture_buf == nil {
return -1
}
((*libavcodec.AVPicture)(unsafe.Pointer(picture))).AvpictureFill(picture_buf, pCodecCtx.PixFmt, pCodecCtx.Width, pCodecCtx.Height)
//Write Header
pFormatCtx.AvformatWriteHeader(nil)
y_size = pCodecCtx.Width * pCodecCtx.Height
pkt.AvNewPacket(y_size * 3)
//Read YUV
_, err = in_file.Read(ffcommon.ByteSliceFromByteP(picture_buf, int(y_size*3/2)))
if err != nil {
fmt.Printf("Could not read input file.%s", err)
return -1
}
picture.Data[0] = picture_buf // Y
picture.Data[1] = (*byte)(unsafe.Pointer(uintptr(unsafe.Pointer(picture_buf)) uintptr(y_size))) // U
picture.Data[2] = (*byte)(unsafe.Pointer(uintptr(unsafe.Pointer(picture_buf)) uintptr(y_size*5/4))) // V
//Encode
ret = pCodecCtx.AvcodecEncodeVideo2(&pkt, picture, &got_picture)
if ret < 0 {
fmt.Printf("Encode Error.n")
return -1
}
if got_picture == 1 {
pkt.StreamIndex = uint32(video_st.Index)
ret = pFormatCtx.AvWriteFrame(&pkt)
}
pkt.AvFreePacket()
//Write Trailer
pFormatCtx.AvWriteTrailer()
fmt.Printf("Encode Successful.n")
if video_st != nil {
video_st.Codec.AvcodecClose()
libavutil.AvFree(uintptr(unsafe.Pointer(picture)))
libavutil.AvFree(uintptr(unsafe.Pointer(picture_buf)))
}
pFormatCtx.Pb.AvioClose()
pFormatCtx.AvformatFreeContext()
in_file.Close()
exec.Command("./lib/ffplay.exe", out_file).Output()
if err != nil {
fmt.Println("play err = ", err)
}
return 0
}
func main() {
os.Setenv("Path", os.Getenv("Path") ";./lib")
ffcommon.SetAvutilPath("./lib/avutil-56.dll")
ffcommon.SetAvcodecPath("./lib/avcodec-58.dll")
ffcommon.SetAvdevicePath("./lib/avdevice-58.dll")
ffcommon.SetAvfilterPath("./lib/avfilter-56.dll")
ffcommon.SetAvformatPath("./lib/avformat-58.dll")
ffcommon.SetAvpostprocPath("./lib/postproc-55.dll")
ffcommon.SetAvswresamplePath("./lib/swresample-3.dll")
ffcommon.SetAvswscalePath("./lib/swscale-5.dll")
genDir := "./out"
_, err := os.Stat(genDir)
if err != nil {
if os.IsNotExist(err) {
os.Mkdir(genDir, 0777) // Everyone can read write and execute
}
}
// go func() {
// time.Sleep(1000)
// exec.Command("./lib/ffplay.exe", "rtmp://localhost/publishlive/livestream").Output()
// if err != nil {
// fmt.Println("play err = ", err)
// }
// }()
main0()
}方法二，用第1个chatgpt生成golang代码：
代码语言：go复制// https://chat.forchange.cn/
// YUV420P像素数据编码为JPEG图片，请用go语言实现。
package main
import (
"bufio"
"fmt"
"image"
"image/color"
"image/jpeg"
"os"
)
func main() {
// 将YUV420P像素数据读入内存
yuvFile, err := os.Open("./out/pic.yuv")
if err != nil {
fmt.Println(err)
return
}
defer yuvFile.Close()
width := 640
height := 360
yuvData := make([]byte, width*height*3/2)
yuvReader := bufio.NewReader(yuvFile)
_, err = yuvReader.Read(yuvData)
if err != nil {
fmt.Println(err)
return
}
// 将YUV420P像素数据转换为RGB格式的图像
img := image.NewRGBA(image.Rect(0, 0, width, height))
for y2 := 0; y2 < height; y2 {
for x := 0; x < width; x {
// 从YUV420P像素数据中获取Y、U、V值
yIndex := y2*width x
uIndex := width*height (y2/2)*(width/2) x/2
vIndex := width*height*5/4 (y2/2)*(width/2) x/2
y3 := float64(yuvData[yIndex])
u := float64(yuvData[uIndex]) - 128.0
v := float64(yuvData[vIndex]) - 128.0
// 将YUV值转换为RGB值
r := y3 1.402*v
g := y3 - 0.344*u - 0.714*v
b := y3 1.772*u
// 将RGB值限制在0-255范围内
r = limit(r, 0, 255)
g = limit(g, 0, 255)
b = limit(b, 0, 255)
// 将RGB值保存到图像中
img.Set(x, y2, color.RGBA{uint8(r), uint8(g), uint8(b), 255})
}
}
// 将图像编码为JPEG图片并保存到文件中
jpegFile, err := os.Create("./out/pic2.jpg")
if err != nil {
fmt.Println(err)
return
}
defer jpegFile.Close()
err = jpeg.Encode(jpegFile, img, nil)
if err != nil {
fmt.Println(err)
return
}
fmt.Println("JPEG image saved to ./out/pic2.jpg")
}
// 将value限制在min和max之间
func limit(value, min, max float64) float64 {
if value < min {
return min
}
if value > max {
return max
}
return value
}方法二，用第2个chatgpt生成golang代码：
代码语言：go复制// https://chatgpt.zcorky.com/ 第一次失败，第二次成功
// YUV420P像素数据编码为JPEG图片，请用go语言实现。不要用第三方库
package main
import (
"bufio"
"bytes"
"fmt"
"image"
"image/color"
"image/jpeg"
"os"
)
func main() {
// 将YUV420P像素数据读入内存
yuvFile, err := os.Open("./out/pic.yuv")
if err != nil {
fmt.Println(err)
return
}
defer yuvFile.Close()
width := 640
height := 360
yuvData := make([]byte, width*height*3/2)
yuvReader := bufio.NewReader(yuvFile)
_, err = yuvReader.Read(yuvData)
if err != nil {
fmt.Println(err)
return
}
// 假设您已经读取了 YUV420P 格式的像素数据，并将其存储在 data 变量中
var yuv []byte = yuvData // YUV420P 数据
// 创建一个新的 RGBA 图像
rgbaImg := image.NewRGBA(image.Rect(0, 0, width, height))
// 将 YUV420P 数据转换为 RGBA 数据
for i := 0; i < width*height; i {
yi := int(yuv[i])
ui := int(yuv[width*height (i/4)])
vi := int(yuv[width*height (width*height/4) (i/4)])
r := float64(yi) 1.4065*(float64(vi)-128)
g := float64(yi) - 0.3455*(float64(ui)-128) - 0.7169*(float64(vi)-128)
b := float64(yi) 1.7790*(float64(ui)-128)
if r < 0 {
r = 0
} else if r > 255 {
r = 255
}
if g < 0 {
g = 0
} else if g > 255 {
g = 255
}
if b < 0 {
b = 0
} else if b > 255 {
b = 255
}
rgbaImg.SetRGBA(i%width, i/width, color.RGBA{
R: uint8(r),
G: uint8(g),
B: uint8(b),
A: 255,
})
}
// 创建 JPEG 图像文件
jpgFile, err := os.Create("./out/pic3.jpg")
if err != nil {
panic(err)
}
defer jpgFile.Close()
// 使用 image/jpeg 包来编码 JPEG 图像
buf := new(bytes.Buffer)
if err := jpeg.Encode(buf, rgbaImg, &jpeg.Options{Quality: 80}); err != nil {
panic(err)
}
_, err = jpgFile.Write(buf.Bytes())
if err != nil {
panic(err)
}
}
