Date: 2018.5.30

YUV處理實用小工具：

1、隔幀分割：

功能說明：cutYUV.cpp 實現YUV檔案分割為兩個子YUV，隔幀寫入YUV，實現幀率擴倍功能。

/*****************************************************
//Function: split  a yuv file to two sub yuv file, fps 
// increase twice.
//Date: 2018-5-30
//Author: SoaringLee
//Modified:
*****************************************************/
 


#include "stdio.h"
#include "stdlib.h"
#include "string"

int main(int argc, char** argv)
{
	unsigned char* y;
	FILE* fp_input, *fp_out1, *fp_out2;
	int width, height, picturesize, framenum = 0;

	printf("Usage: splitYUV.exe  srcyuv dstyuv1 dstyuv2 width height\n\n");

	if (argc < 5)
	{
		return
 
 -1;
	}


	width = atoi(argv[4]);
	height = atoi(argv[5]);

	fp_input = fopen(argv[1], "rb");
	if (NULL == fp_input)
	{
		printf("open %s fail!\n", argv[1]);
		return -1;
	}

	fp_out1 = fopen(argv[2], "wb");
	if (NULL == fp_out1)
	{
		printf("open %s fail!\n", argv[2]);
		return -1;
	}

	fp_out2 = fopen
 
(argv[3], "wb");
	if (NULL == fp_out2)
	{
		printf("open %s fail!\n", argv[3]);
		return -1;
	}

	picturesize = width*height * 3 / 2;//++YUV420

	y = (unsigned char*)malloc(picturesize*sizeof(unsigned char*));

	while (fread(y, 1, picturesize, fp_input) == picturesize)
	{
		if (framenum % 2 == 0)
		{
			fwrite(y, 1, picturesize, fp_out1);
		}
		else
		{
			fwrite(y, 1, picturesize, fp_out2);
		}
		framenum++;
	}

	printf("[SplitYUV] split %s to %s and %s successfully!!!\n", argv[1], argv[2], argv[3]);

	free(y);
	y = NULL;
	fclose(fp_input);
	fclose(fp_out1);
	fclose(fp_out2);

	return 0;
}

另外，還可以通過ffmpeg實現隔幀分割的功能：

ffmpeg -r 2 -s WxH -i rawbitstream.yuv -filter:v select="mod(n-1\,2)" \
-c:v rawvideo -r 1 -format rawvideo -pix_fmt yuv420p -an odd.yuv

ffmpeg -r 2 -s WxH -i rawbitstream.yuv -filter:v select="not(mod(n-1\,2))" \
-c:v rawvideo -r 1 -format rawvideo -pix_fmt yuv420p -an even.yuv

2、分段分割：

Extract some YUV frames from large yuv File
從第0幀開始擷取30幀：

ffmpeg -s widthxheight -i input.yuv -c:v rawvideo -filter:v select="gt(n\, -1)" -vframes 30 out30.yuv

或者：

ffmpeg -s widthxheight -i input.yuv -c:v rawvideo -filter:v select="between(n\, 0\, 29)" out30.yuv

或者：

ffmpeg -r 1 -ss 0 -i input.yuv -vcodec copy -vframes 30 output.yuv

更多命令使用參考：

THE END!