1 files changed, 71 insertions, 15 deletions

diff --git a/src/advtime.c b/src/advtime.c
index 5dbe6d7..6144cc3 100644
--- a/src/advtime.c
+++ b/src/advtime.c
@@ -1,13 +1,37 @@
+#define _XOPEN_SOURCE 500
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <unistd.h>
 
 #include "video_decode.h"
 
-static int64_t
+static 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);
+}
+
+static double
 frame_average(struct video_frame *frame)
 {
-	int64_t average = 0;
+	double average = 0;
 	uint8_t *row = frame->data;
 	uint8_t *col = NULL;
 
@@ -23,31 +47,63 @@ frame_average(struct video_frame *frame)
 	return average / (frame->width * frame->height);
 }
 
+static void
+usage(void)
+{
+	fprintf(stderr, "advtime [-a] [-d] FILE\n");
+	exit(EXIT_FAILURE);
+}
+
 int
 main(int argc, char **argv)
 {
 	struct video_decode *vd;
-	struct video_frame *frame;
-	int ret;
+	struct video_frame *frame_a;
+	struct video_frame *frame_b;
+	int ret, ch;
+	int diff_flag = 0, average_flag = 0;
 	int64_t timestamp = 0;
 
-	if (argc < 2)
-		return 1;
+	while ((ch = getopt(argc, argv, "ad")) != -1) {
+		switch (ch) {
+		case 'a':
+			average_flag = 1;
+			break;
+		case 'd':
+			diff_flag = 1;
+			break;
+		default:
+			usage();
+			/* NOTREACHED */
+		}
+	}
+	argc -= optind;
+	argv += optind;
+
+	if (argc < 1)
+		usage();
 
-	if (argc == 3 && strtol(argv[2], NULL, 10) > 0)
-		timestamp = strtol(argv[2], NULL, 10);
+	if (argc == 2 && strtol(argv[1], NULL, 10) > 0)
+		timestamp = strtol(argv[1], NULL, 10);
 
-	ret = video_decode_init(&vd, argv[1], timestamp);
+	ret = video_decode_init(&vd, argv[0], timestamp);
 	if (ret < 0)
 		return -ret;
 
-	while (video_decode_get_frame(vd, &frame) == 0) {
-		printf("%ld\n", frame_average(frame));
-		video_decode_free_frame(&frame);
-	}
+	ret = video_decode_get_frame(vd, &frame_a);
+	if (ret < 0)
+		return -ret;
 
-//	pgm_save(frame->data, frame->stride, frame->width, frame->height,
-//		 argv[2]);
+	while (video_decode_get_frame(vd, &frame_b) == 0) {
+		if (average_flag == 1)
+			printf("%f\n", frame_average(frame_a));
+		if (diff_flag == 1)
+			printf("%f\n", frame_diff(frame_a, frame_b));
+		video_decode_free_frame(&frame_a);
+		frame_a = frame_b;
+	}
 
+	video_decode_free_frame(&frame_b);
 	video_decode_uninit(&vd);
+	return EXIT_SUCCESS;
 }