YUV420SP to YUV420P

最近做TI DM365的solution, 發現出來的畫面有抖動，於是就想抓RAW data出來看看是sensor有問題還是encode出了問題，sensor出來的資料是RGB的，通過Previewer後就變成了YUV420SP, 抓了RAW data出來之後用YUVtools一看，整個畫面都是灰色的，感覺只有Y值work了，UV都沒了，於是又去網上download其他的YUV tools, 結果還是一樣，後來發現一般的YUV tools只支援普通的YUV420格式，即YUV420P, 於是去找解析YUV420SP的tool, 發現還不太好找，於是就自己寫了一個轉換工具，將YUV420SP的轉成YUV420P的格式，轉了之後用YUV tools 一看，顏色全對了。

 

下面就是源碼：

/*
YYYYYYYYYYYYY                                YYYYYYYYYYYYY
YYYYYYYYYYYYY       -->                      YYYYYYYYYYYYY
YYYYYYYYYYYYY                                YYYYYYYYYYYYY
YYYYYYYYYYYYY                                YYYYYYYYYYYYY
CbCrCbCr                                     CbCbCbCb
CbCrCbCr                                     CrCrCrCr

YYYYYYYY...      -->   YYYYYYYY...
CbCrCbCr....     -->   CbCb.....  CrCr......
*/

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/stat.h>

int main(int argc, char* argv[])
{
 int i;
 int idx;
 int width;
 int height;
 int pixels;
 int frame_no;
 FILE *inputfp = NULL;
 FILE *outputfp = NULL;
 unsigned char *pBuffer;
 struct stat state;

 if (argc != 5)
 {
  fprintf(stderr, "Usage : %s <input file name> <output file name> <width> <height>/n",argv[0]);
  return -1;
 }

 width = atoi(argv[3]);
 height = atoi(argv[4]);

 if(width <= 0 || height <= 0)
 {
  fprintf(stderr, "parameter error [width = %d, height=%d]/n",width, height);
  return -1;
 }

 if (stat(argv[1], &state) < 0)
 {
  fprintf(stderr, "Faile to stat %s/n",argv[1]);
  return -1;
 }
 frame_no = (state.st_size/((width*height/2)*3));

 inputfp = fopen(argv[1], "rb");
 if (!inputfp)
 {
  fprintf(stderr, "fopen failed for input file[%s]/n",argv[1]);
  return -1;
 }

 outputfp = fopen(argv[2], "wb");
 if (!outputfp)
 {
  fprintf(stderr, "fopen failed for output file[%s]/n",argv[2]);
  return -1;
 }

 pixels = width * height;
 pBuffer = (unsigned char *)malloc(pixels);

 for (i=0; i<frame_no; i++)
 {
  // Read Y
  fread (pBuffer, pixels, sizeof(unsigned char), inputfp);

  // Write Y
  fwrite(pBuffer, pixels, sizeof(unsigned char), outputfp);

  // Read Cb Cr
  fread (pBuffer, (pixels/2), sizeof(unsigned char), inputfp);

  // Write Cb
  for(idx = 0; idx <  (pixels/2); idx+=2)
  {
   fwrite((pBuffer + idx), 1, sizeof(unsigned char), outputfp);
  }

  // Write Cr
  for(idx = 1; idx <  (pixels/2); idx+=2)
  {
   fwrite((pBuffer + idx), 1, sizeof(unsigned char), outputfp);
  }
 }
 
 free(pBuffer);
 fclose(inputfp);
 fclose(outputfp);
 return 0;
}