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#define _XOPEN_SOURCE 700
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "video_decode.h"
#include "util.h"
int
pgm_read(char *filename, unsigned char **buf, int *xsize, int *ysize)
{
FILE *f = NULL;
unsigned char *b = NULL;
int width, height;
ssize_t n;
f = fopen(filename, "r");
if (f == NULL)
return -1;
if (fscanf(f, "P5\n%d %d\n255\n", &width, &height) == 0)
return -1;
if (width * height <= 0)
goto fail;
if ((b = malloc(width * height)) == NULL)
goto fail;
if ((n = fread(b, 1, width * height, f)) == 0 || n != width * height)
goto fail;
fclose(f);
*buf = b;
*xsize = width;
*ysize = height;
return 0;
fail:
if (f) fclose(f);
if (b) free(b);
return -1;
}
int
pgm_save(unsigned char *buf, int wrap, int xsize, int ysize, char *filename)
{
FILE *f;
int i;
f = fopen(filename, "w");
if (f == NULL)
return -1;
fprintf(f, "P5\n%d %d\n%d\n", xsize, ysize, 255);
for(i = 0; i < ysize; i++)
fwrite(buf + i * wrap, 1, xsize, f);
fclose(f);
return 0;
}
void
frame_mix(struct video_frame *frame_a, struct video_frame *frame_b)
{
uint8_t *row_a = frame_a->data, *col_a = NULL;
uint8_t *row_b = frame_b->data, *col_b = NULL;
for (int y = 0; y < frame_a->height; ++y) {
col_a = row_a;
col_b = row_b;
for (int x = 0; x < frame_a->width; ++x) {
if (x > frame_a->width / 2)
*col_a = *col_b;
col_a++;
col_b++;
}
row_a += frame_a->stride;
row_b += frame_b->stride;
}
}
double
frame_diff(struct video_frame *frame_a, struct video_frame *frame_b)
{
double average = 0;
uint8_t *row_a = frame_a->data, *col_a = NULL;
uint8_t *row_b = frame_b->data, *col_b = NULL;
for (int y = 0; y < frame_a->height; ++y) {
col_a = row_a;
col_b = row_b;
for (int x = 0; x < frame_a->width; ++x) {
average += abs(*col_a - *col_b);
col_a++;
col_b++;
}
row_a += frame_a->stride;
row_b += frame_b->stride;
}
return average / (frame_a->width * frame_a->height);
}
double
frame_average(struct video_frame *frame)
{
double average = 0;
uint8_t *row = frame->data;
uint8_t *col = NULL;
for (int y = 0; y < frame->height; ++y) {
col = row;
for (int x = 0; x < frame->width; ++x) {
average += *col;
col++;
}
row += frame->stride;
}
return average / (frame->width * frame->height);
}
/* print time in format: "hh:mm:ss.xxx" */
void
print_time(int64_t msec) {
int hh = msec / 1000 / 60 / 60;
msec -= hh * 1000 * 60 * 60;
int mm = msec / 1000 / 60;
msec -= mm * 1000 * 60;
int ss = msec / 1000;
msec -= ss * 1000;
printf("%02d:%02d:%02d.%03jd", hh, mm, ss, msec);
}
int
sobel(struct video_frame *frame, unsigned char **d)
{
unsigned char *data;
unsigned char *p = frame->data;
int x,y;
int Yx, Yy, Y;
data = malloc(frame->width * frame->height);
if (data == NULL)
return -1;
for (y = 1; y < frame->height-1; ++y) {
for (x = 1; x < frame->width-1; ++x) {
Yx = (+1 * p[(y-1) * frame->stride + (x-1)]
-1 * p[(y-1) * frame->stride + (x+1)]
+2 * p[(y ) * frame->stride + (x-1)]
-2 * p[(y ) * frame->stride + (x+1)]
+1 * p[(y+1) * frame->stride + (x-1)]
-1 * p[(y+1) * frame->stride + (x+1)]);
Yx = abs(Yx);
Yy = (+1 * p[(y-1) * frame->stride + (x-1)]
+2 * p[(y-1) * frame->stride + (x )]
+1 * p[(y-1) * frame->stride + (x+1)]
-1 * p[(y+1) * frame->stride + (x-1)]
-2 * p[(y+1) * frame->stride + (x )]
-1 * p[(y+1) * frame->stride + (x+1)]);
Yy = abs(Yy);
Y = (Yx > Yy ? Yx : Yy) / 4;
if (Y > 255) Y = 255;
data[y * frame->width + x] = Y;
}
}
*d = data;
return 0;
}
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