C++ 在C/C+中写入YUV图像帧的问题+;
我正在尝试将取自OpenGL glReadPixels()的RGB帧转换为YUV帧,并将YUV帧写入文件(.YUV)。稍后,我想将其写入命名的_管道作为FFMPEG的输入,但现在我只想将其写入文件,并使用YUV图像查看器查看图像结果。因此,暂时不要理会“向管道写入”的问题 运行代码后,我遇到以下错误:C++ 在C/C+中写入YUV图像帧的问题+;,c++,image-processing,file-io,rgb,yuv,C++,Image Processing,File Io,Rgb,Yuv,我正在尝试将取自OpenGL glReadPixels()的RGB帧转换为YUV帧,并将YUV帧写入文件(.YUV)。稍后,我想将其写入命名的_管道作为FFMPEG的输入,但现在我只想将其写入文件,并使用YUV图像查看器查看图像结果。因此,暂时不要理会“向管道写入”的问题 运行代码后,我遇到以下错误: YUV Image Viewer软件中显示的帧数始终是我在程序中声明的帧数的1/3。当我将fps声明为10时,我只能查看3帧。当我声明fps为30时,我只能查看10帧。但是,当我在文本编辑器中查看
int frameCounter = 1;
int windowWidth = 0, windowHeight = 0;
unsigned char *yuvBuffer;
unsigned long bufferLength = 0;
unsigned long frameLength = 0;
int fps = 10;
void display(void) {
/* clear the color buffers */
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
/* DRAW some OPENGL animation, i.e. cube, sphere, etc
.......
.......
*/
glutSwapBuffers();
if ((frameCounter % fps) == 1){
bufferLength = 0;
windowWidth = glutGet(GLUT_WINDOW_WIDTH);
windowHeight = glutGet (GLUT_WINDOW_HEIGHT);
frameLength = (long) (windowWidth * windowHeight * 1.5 * fps) + 100; // YUV 420 length (width*height*1.5) + header length
yuvBuffer = new unsigned char[frameLength];
write_yuv_frame_header();
}
write_yuv_frame();
frameCounter = (frameCounter % fps) + 1;
if ( (frameCounter % fps) == 1){
snprintf(filename, 100, "out/image-%d.yuv", seq_num);
ofstream out(filename, ios::out | ios::binary);
if(!out) {
cout << "Cannot open file.\n";
}
out.write (reinterpret_cast<char*> (yuvBuffer), bufferLength);
out.close();
bufferLength = 0;
delete[] yuvBuffer;
}
}
void write_yuv_frame_header (){
char *yuvHeader = new char[100];
sprintf (yuvHeader, "YUV4MPEG2 W%d H%d F%d:1 Ip A0:0 C420mpeg2 XYSCSS=420MPEG2\n", windowWidth, windowHeight, fps);
memcpy ((char*)yuvBuffer + bufferLength, yuvHeader, strlen(yuvHeader));
bufferLength += strlen (yuvHeader);
delete (yuvHeader);
}
void write_yuv_frame() {
int width = glutGet(GLUT_WINDOW_WIDTH);
int height = glutGet(GLUT_WINDOW_HEIGHT);
memcpy ((void*) (yuvBuffer+bufferLength), (void*) "FRAME\n", 6);
bufferLength +=6;
long length = windowWidth * windowHeight;
long yuv420FrameLength = (float)length * 1.5;
long lengthRGB = length * 3;
unsigned char *rgb = (unsigned char *) malloc(lengthRGB * sizeof(unsigned char));
unsigned char *yuvdest = (unsigned char *) malloc(yuv420FrameLength * sizeof(unsigned char));
glReadPixels(0, 0, windowWidth, windowHeight, GL_RGB, GL_UNSIGNED_BYTE, rgb);
int r, g, b, y, u, v, ypos, upos, vpos;
for (int j = 0; j < windowHeight; ++j){
for (int i = 0; i < windowWidth; ++i){
r = (int)rgb[(j * windowWidth + i) * 3 + 0];
g = (int)rgb[(j * windowWidth + i) * 3 + 1];
b = (int)rgb[(j * windowWidth + i) * 3 + 2];
y = (int)(r * 0.257 + g * 0.504 + b * 0.098) + 16;
u = (int)(r * 0.439 + g * -0.368 + b * -0.071) + 128;
v = (int)(r * -0.148 + g * -0.291 + b * 0.439 + 128);
ypos = j * windowWidth + i;
upos = (j/2) * (windowWidth/2) + i/2 + length;
vpos = (j/2) * (windowWidth/2) + i/2 + length + length/4;
yuvdest[ypos] = y;
yuvdest[upos] = u;
yuvdest[vpos] = v;
}
}
memcpy ((void*) (yuvBuffer + bufferLength), (void*)yuvdest, yuv420FrameLength);
bufferLength += yuv420FrameLength;
free (yuvdest);
free (rgb);
}
int frameCounter=1;
int windowWidth=0,windowHeight=0;
未签名字符*yuvBuffer;
无符号长缓冲区长度=0;
无符号长帧长度=0;
int fps=10;
作废显示(作废){
/*清除颜色缓冲区*/
glClear(GL_颜色_缓冲_位| GL_深度_缓冲_位);
/*绘制一些OPENGL动画,例如立方体、球体等
.......
.......
*/
glutSwapBuffers();
如果((帧计数器%fps)==1){
缓冲长度=0;
windowWidth=glutGet(GLUT\u窗口\u宽度);
窗口高度=glutGet(GLUT\U窗口高度);
frameLength=(长)(窗宽*窗高*1.5*fps)+100;//YUV 420长度(宽*高*1.5)+页眉长度
yuvBuffer=新的无符号字符[frameLength];
写入帧头();
}
写下你的框架();
帧计数器=(帧计数器%fps)+1;
如果((帧计数器%fps)==1){
snprintf(文件名,100,“输出/图像-%d.yuv”,序号);
输出流(文件名,ios::out | ios::binary);
如果(!out){
cout在我看来,对于4:2:0数据,每帧的字节数太多。根据链接到的规范,200x200像素4:2:0帧的字节数应该是200*200*3/2=60000。但是您有大约90000个字节。查看您的代码,我看不到从4:4:4转换到4:2:0的位置。因此,您有两个选择—设置标头设置为4:4:4,或者在写入之前将YCbCr数据转换为4:2:0。我编译了您的代码,在计算upos和vpos值时肯定会出现问题。
对我来说,这很有效(RGB到YUV NV12):
我已经将字节数设置为200*200*3/2(在yuv420FrameLength中)。因此,对于200*200像素的图像,yuv缓冲区的大小为60000。我还将帧长度设置为width*height*1.5*fps。此外,以下代码以4:2:0格式定位数据:ypos=j*windowWidth+I;upos=(j/2)*(windowWidth/2)+i/2+length;vpos=(j/2)*(windowWidth/2)+i/2+length+length/4;yuvdest[ypos]=y;yuvdest[upos]=u;yuvdest[vpos]=v;啊,对不起。我下载了你的输出文件,在文本编辑器中查看时,第一个“帧”和第二个“帧”之间大约有90000字节,但事实证明,这是因为它被文本编辑器转换为UTF8。在十六进制编辑器中查看它,只有60000字节,这似乎是正确的。你能发布前后的图片吗?这可能会让事情变得更加明显。此外,如果你写出4:4:4的数据(使用正确的标题),会发生什么?那么你得到所有的帧了吗?还有一件事-我注意到维基百科的链接提到标题以“YUVMPEG4”(结尾有一个空格)开头,所有字段都以一个空格开头。YUV标记和宽度标记之间需要2个空格吗?(我在维基百科上不清楚是否如此。)你能在写数据的地方发布代码吗?另外,你能在调试器中验证当你将u和v从有符号整数转换为无符号字符时,你得到了正确的位模式吗?你解决了这个问题吗?
vpos = length + (windowWidth * (j/2)) + (i/2)*2;
upos = vpos + 1;