emote2ss

commit d6d66ace68800dfd7cc40a42b41c8e0642cfc178
parent 0b1662e3fee888fddaa09c8fb362f05de9b5108e
Author: bsandro <email@bsandro.tech>
Date:   Thu,  4 May 2023 00:13:31 +0300

Decoding frames of an animation

Diffstat:
M
src/main.c
 | 
89
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--------------------

1 file changed, 67 insertions(+), 22 deletions(-)
diff --git a/src/main.c b/src/main.c
@@ -1,8 +1,15 @@
+/**
+ * Based on the libwebp example program "anim_dump"
+ */
+
 #include <stdio.h>
 #include "webp/decode.h"
 #include "webp/demux.h"
 #include <stdbool.h>
 #include <stdlib.h>
+#include <assert.h>
+
+#define NUM_CHANNELS 4
 
 static void print_webp_version() {
 	int dec_ver = WebPGetDecoderVersion();
@@ -21,30 +28,52 @@ typedef struct {
 typedef struct {
 	int width, height, bgcolor, loop_count;
 	DecodedFrame *frames;
-	uint32_t frames_count;
+	uint32_t frame_count;
 	void *raw_mem;
 } AnimatedImage;
 
+void alloc_image(AnimatedImage *img, uint32_t frame_count) {
+	uint8_t *mem = NULL;
+	DecodedFrame *frames = NULL;
+	const uint64_t rgba_size = img->width * img->height * NUM_CHANNELS;
+	const uint64_t img_size = frame_count * rgba_size * sizeof(uint8_t);
+	const uint64_t frames_size = frame_count * sizeof(DecodedFrame);
+
+	assert(img_size == (size_t)img_size);
+	assert(frames_size == (size_t)frames_size);
+
+	printf("img mem: %lu\nframes mem: %lu\n", img_size, frames_size);
+
+	mem = malloc(img_size);
+	frames = malloc(frames_size);
+	assert(mem != NULL);
+	assert(frames != NULL);
+
+	for (uint32_t i=0; i<frame_count; ++i) {
+		frames[i].rgba = mem+i*rgba_size;
+		frames[i].duration = 0;
+		frames[i].is_key = false;
+	}
+	img->frame_count = frame_count;
+	img->frames = frames;
+	img->raw_mem = mem;
+}
+
 int read_file(const char *fname, const uint8_t **data, size_t *size) {
-	if (data == NULL || size == NULL) return -1;
+	assert(data != NULL);
+	assert(size != NULL);
+
 	*data = NULL;
 	*size = 0;
 	FILE *infile = fopen(fname, "rb");
-	if (infile == NULL) {
-		fprintf(stderr, "cannot open file %s\n", fname);
-		return -1;
-	}
+	assert(infile != NULL);
 	fseek(infile, 0, SEEK_END);
 	size_t fsize = ftell(infile);
 	printf("%s: %zu bytes\n", fname, fsize);
 	fseek(infile, 0, SEEK_SET);
 
 	uint8_t *fdata = malloc(fsize+1);
-	if (fdata == NULL) {
-		fclose(infile);
-		fprintf(stderr, "malloc failed\n");
-		return -1;
-	}
+	assert(fdata != NULL);
 	fdata[fsize] = '\0';
 	int ok = (fread(fdata, fsize, 1, infile)==1);
 	fclose(infile);
@@ -54,10 +83,8 @@ int read_file(const char *fname, const uint8_t **data, size_t *size) {
 		free(fdata);
 		return -1;
 	}
-
 	*data = fdata;
 	*size = fsize;
-
 	return 0;
 }
 
@@ -79,11 +106,7 @@ int read_webp(const char *fname, AnimatedImage *anim) {
 	}
 
 	WebPAnimDecoder *dec = WebPAnimDecoderNew(&webp_data, NULL);
-	if (dec == NULL) {
-		fprintf(stderr, "decoder error\n");
-		// @todo cleanup
-		return -1;
-	}
+	assert(dec != NULL);
 
 	WebPAnimInfo anim_info;
 	if (!WebPAnimDecoderGetInfo(dec, &anim_info)) {
@@ -91,13 +114,35 @@ int read_webp(const char *fname, AnimatedImage *anim) {
 		// @todo cleanup
 		return -1;
 	}
-	anim->frames_count = anim_info.frame_count;
+
+	alloc_image(anim, anim_info.frame_count);
 	anim->width = anim_info.canvas_width;
 	anim->height = anim_info.canvas_height;
 	anim->loop_count = anim_info.loop_count;
 	anim->bgcolor = anim_info.bgcolor;
 
+	uint32_t frame_index = 0;
+	int prev_ts = 0;
+	while (WebPAnimDecoderHasMoreFrames(dec)) {
+		DecodedFrame *frame;
+		uint8_t *curr_rgba, *frame_rgba;
+		int ts;
+		if (!WebPAnimDecoderGetNext(dec, &frame_rgba, &ts)) {
+			fprintf(stderr, "error decoding frame %d\n", frame_index);
+			return -1;
+		}
+		assert(frame_index < anim_info.frame_count);
+		frame = &anim->frames[frame_index];
+		curr_rgba = frame->rgba;
+		frame->duration = ts - prev_ts;
+		memcpy(curr_rgba, frame_rgba, anim->width * anim->height * NUM_CHANNELS);
+		// ...
+		++frame_index;
+		prev_ts = ts;
+	}
+
 	WebPDataClear(&webp_data);
+	WebPAnimDecoderDelete(dec);
 	return 0;
 }
 
@@ -106,9 +151,9 @@ int main(int argc, const char **argv) {
 
 	if (argc >= 1) {
 		for (int i=1; i<argc; ++i) {
-			AnimatedImage anim = {0};
-			read_webp(argv[i], &anim);
-			printf("dimensions: %dx%d\nframes: %d\n", anim.width, anim.height, anim.frames_count);
+			AnimatedImage img = {0};
+			assert(read_webp(argv[i], &img) == 0);
+			printf("dimensions: %dx%d\nframes: %d\n", img.width, img.height, img.frame_count);
 		}
 	}