ppm-reader.c

ppm-reader.c

#include <netpbm/pam.h>
#include <stdbool.h>
#include <stdint.h>

int main(int argc, char **argv){
  int c;
  while((c = getc(stdin)) != EOF){
    ungetc(c, stdin);
    struct pam inpam;
    tuple *tuplerow;
    unsigned int row;

    pm_init(argv[0], 0);

    pnm_readpaminit(stdin, &inpam, PAM_STRUCT_SIZE(tuple_type));

    tuplerow = pnm_allocpamrow(&inpam);

    for(row = 0; row < inpam.height; row++){
      unsigned int column;
      pnm_readpamrow(&inpam, tuplerow);
      for(column = 0; column < inpam.width; ++column){
        // Process pixels in here however you want.
        // This is a pointer to inpam.depth many long values
        // inpam.depth seems to always be 3 for ffmpeg output, but I wouldn't swear that's always true
        unsigned long *pixel = tuplerow[column];
      }
    }
    pnm_freepamrow(tuplerow);
  }
}

video-processor

ffmpeg -i $1 -f image2pipe -vcodec ppm pipe:1 | ppm-reader