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gif2webp: Support a 'min' and 'max' key frame interval

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Change-Id: If910c8849d7210e7227db0f45affa26fce7da102
This commit is contained in:
Urvang Joshi
2013-09-12 13:41:09 -07:00
parent 80b54e1c69
commit d538cea8c2
6 changed files with 633 additions and 256 deletions
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2
examples/Makefile.am
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@ -30,7 +30,7 @@ cwebp_CPPFLAGS = $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE)
cwebp_CPPFLAGS += $(JPEG_INCLUDES) $(PNG_INCLUDES) $(TIFF_INCLUDES)
cwebp_LDADD = ../src/libwebp.la $(JPEG_LIBS) $(PNG_LIBS) $(TIFF_LIBS)
gif2webp_SOURCES = gif2webp.c
gif2webp_SOURCES = gif2webp.c gif2webp_util.c
gif2webp_CPPFLAGS = $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE) $(GIF_INCLUDES)
gif2webp_LDADD = libexampleutil.la ../src/mux/libwebpmux.la ../src/libwebp.la
gif2webp_LDADD += $(GIF_LIBS)

380
examples/gif2webp.c
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@ -14,7 +14,6 @@
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_CONFIG_H
@ -25,78 +24,48 @@
#include "webp/encode.h"
#include "webp/mux.h"
#include "./example_util.h"
#include "./gif2webp_util.h"
#define GIF_TRANSPARENT_MASK 0x01
#define GIF_DISPOSE_MASK 0x07
#define GIF_DISPOSE_SHIFT 2
#define TRANSPARENT_COLOR 0x00ffffff
#define WHITE_COLOR 0xffffffff
#define MAX_CACHE_SIZE 30
//------------------------------------------------------------------------------
// Global variables gathered in a struct.
static struct {
int transparent_index; // Index of transparent color in the color map.
int is_first_frame;
size_t count_since_key_frame; // Frames seen since the last key frame.
size_t key_frame_interval; // Max distance between key frames.
} kParams;
static int transparent_index = -1; // Index of transparent color in the map.
static int is_first_frame = 1; // Whether we are processing the first frame.
static void ClearRectangle(WebPPicture* const picture,
int left, int top, int width, int height) {
int j;
for (j = top; j < top + height; ++j) {
uint32_t* const dst = picture->argb + j * picture->argb_stride;
int i;
for (i = left; i < left + width; ++i) {
dst[i] = TRANSPARENT_COLOR;
}
static void SanitizeKeyFrameIntervals(size_t* const kmin_ptr,
size_t* const kmax_ptr) {
size_t kmin = *kmin_ptr;
size_t kmax = *kmax_ptr;
if (kmin == 0) kmin = ~0; // Disable keyframe insertion.
if (kmax == 0) kmax = ~0;
if (kmin >= kmax) {
kmin = kmax - 1;
fprintf(stderr,
"WARNING: Setting kmin = %zu, so that kmin < kmax.\n", kmin);
} else if (kmin < (kmax / 2 + 1)) {
// This ensures that cache.keyframe + kmin >= kmax is always true. So, we
// can flush all the frames in the ‘count_since_key_frame == kmax’ case.
kmin = (kmax / 2 + 1);
fprintf(stderr,
"WARNING: Setting kmin = %zu, so that kmin >= kmax / 2 + 1.\n",
kmin);
}
}
typedef struct WebPFrameRect {
int x_offset, y_offset, width, height;
} WebPFrameRect;
// Clear pixels in 'picture' within given 'rect' to transparent color.
static void ClearPicture(WebPPicture* const picture,
const WebPFrameRect* const rect) {
if (rect != NULL) {
ClearRectangle(picture, rect->x_offset, rect->y_offset,
rect->width, rect->height);
} else {
ClearRectangle(picture, 0, 0, picture->width, picture->height);
}
}
// TODO: Also used in picture.c. Move to a common location.
static void CopyPlane(const uint8_t* src, int src_stride,
uint8_t* dst, int dst_stride, int width, int height) {
while (height-- > 0) {
memcpy(dst, src, width);
src += src_stride;
dst += dst_stride;
}
}
// Given 'curr_frame' and its 'rect', blend it in the 'canvas'.
static void BlendCurrentFrameInCanvas(const WebPPicture* const curr_frame,
const WebPFrameRect* const rect,
WebPPicture* const canvas) {
int j;
assert(canvas->width == curr_frame->width &&
canvas->height == curr_frame->height);
for (j = rect->y_offset; j < rect->y_offset + rect->height; ++j) {
int i;
for (i = rect->x_offset; i < rect->x_offset + rect->width; ++i) {
const uint32_t src =
curr_frame->argb[j * curr_frame->argb_stride + i];
const int src_alpha = src >> 24;
if (src_alpha != 0) {
canvas->argb[j * canvas->argb_stride + i] = src;
}
}
// Limit the max number of frames that are allocated.
if (kmax - kmin > MAX_CACHE_SIZE) {
fprintf(stderr,
"WARNING: Setting kmin = %zu, so that kmax - kmin <= 30.\n", kmin);
kmin = kmax - MAX_CACHE_SIZE;
}
*kmin_ptr = kmin;
*kmax_ptr = kmax;
}
static void Remap(const uint8_t* const src, const GifFileType* const gif,
@ -110,87 +79,11 @@ static void Remap(const uint8_t* const src, const GifFileType* const gif,
for (i = 0; i < len; ++i) {
const GifColorType c = colors[src[i]];
dst[i] = (src[i] == kParams.transparent_index) ? TRANSPARENT_COLOR
dst[i] = (src[i] == transparent_index) ? TRANSPARENT_COLOR
: c.Blue | (c.Green << 8) | (c.Red << 16) | (0xff << 24);
}
}
// Returns true if 'curr' frame is a key frame, that is, it can be decoded
// independently of 'prev' canvas.
static int IsKeyFrame(const WebPPicture* const curr,
const WebPFrameRect* const curr_rect,
const WebPPicture* const prev) {
int i, j;
int is_key_frame = 1;
if (kParams.is_first_frame) return 1;
// If previous canvas (with previous frame disposed) is all transparent,
// current frame is a key frame.
for (i = 0; i < prev->width; ++i) {
for (j = 0; j < prev->height; ++j) {
const uint32_t prev_alpha = (prev->argb[j * prev->argb_stride + i]) >> 24;
if (prev_alpha != 0) {
is_key_frame = 0;
break;
}
}
if (!is_key_frame) break;
}
if (is_key_frame) return 1;
// If current frame covers the whole canvas and does not contain any
// transparent pixels that depend on previous canvas, then current frame is
// a key frame.
if (curr_rect->width == curr->width && curr_rect->height == curr->height) {
assert(curr_rect->x_offset == 0 && curr_rect->y_offset == 0);
is_key_frame = 1;
for (j = 0; j < prev->height; ++j) {
for (i = 0; i < prev->width; ++i) {
const uint32_t prev_alpha =
(prev->argb[j * prev->argb_stride + i]) >> 24;
const uint32_t curr_alpha =
(curr->argb[j * curr->argb_stride + i]) >> 24;
if (curr_alpha != 0xff && prev_alpha != 0) {
is_key_frame = 0;
break;
}
}
if (!is_key_frame) break;
}
if (is_key_frame) return 1;
}
return 0;
}
// Convert 'curr' frame to a key frame.
static void ConvertToKeyFrame(WebPPicture* const curr,
const WebPPicture* const prev,
WebPFrameRect* const rect) {
int j;
assert(curr->width == prev->width && curr->height == prev->height);
// Replace transparent pixels of current canvas with those from previous
// canvas (with previous frame disposed).
for (j = 0; j < curr->height; ++j) {
int i;
for (i = 0; i < curr->width; ++i) {
uint32_t* const curr_pixel = curr->argb + j * curr->argb_stride + i;
const int curr_alpha = *curr_pixel >> 24;
if (curr_alpha == 0) {
*curr_pixel = prev->argb[j * prev->argb_stride + i];
}
}
}
// Frame rectangle now covers the whole canvas.
rect->x_offset = 0;
rect->y_offset = 0;
rect->width = curr->width;
rect->height = curr->height;
}
// Read the GIF image frame.
static int ReadFrame(GifFileType* const gif, WebPFrameRect* const gif_rect,
WebPPicture* const sub_image, WebPPicture* const curr) {
@ -242,11 +135,12 @@ static int ReadFrame(GifFileType* const gif, WebPFrameRect* const gif_rect,
return ok;
}
// Optimize the image frame for WebP.
static void OptimizeFrame(const WebPFrameRect* const gif_rect,
WebPPicture* const curr, WebPPicture* const prev,
WebPPicture* const sub_image,
WebPMuxFrameInfo* const info) {
// Optimize the image frame for WebP and encode it.
static int OptimizeAndEncodeFrame(
const WebPConfig* const config, const WebPFrameRect* const gif_rect,
WebPPicture* const curr, WebPPicture* const prev_canvas,
WebPPicture* const curr_canvas, WebPPicture* const sub_image,
WebPMuxFrameInfo* const info, WebPFrameCache* const cache) {
WebPFrameRect rect = *gif_rect;
// Snap to even offsets (and adjust dimensions if needed).
@ -255,82 +149,69 @@ static void OptimizeFrame(const WebPFrameRect* const gif_rect,
rect.x_offset &= ~1;
rect.y_offset &= ~1;
// Make this a key frame if needed.
if (IsKeyFrame(curr, &rect, prev)) {
kParams.count_since_key_frame = 0;
} else {
++kParams.count_since_key_frame;
if (kParams.count_since_key_frame > kParams.key_frame_interval) {
ConvertToKeyFrame(curr, prev, &rect);
kParams.count_since_key_frame = 0;
}
if (!WebPPictureView(curr, rect.x_offset, rect.y_offset,
rect.width, rect.height, sub_image)) {
return 0;
}
if (kParams.count_since_key_frame == 0) {
info->blend_method = WEBP_MUX_NO_BLEND; // Key frame, so no need to blend.
} else {
info->blend_method = WEBP_MUX_BLEND; // The blending method in GIF.
}
// Update the canvas so that it can be used to check for and/or create an
// key frame in the next iterations.
if (info->blend_method == WEBP_MUX_NO_BLEND) {
CopyPlane((uint8_t*)curr->argb, 4 * curr->argb_stride, (uint8_t*)prev->argb,
4 * prev->argb_stride, 4 * curr->width, curr->height);
} else {
BlendCurrentFrameInCanvas(curr, gif_rect, prev);
}
WebPPictureView(curr, rect.x_offset, rect.y_offset, rect.width, rect.height,
sub_image);
info->x_offset = rect.x_offset;
info->y_offset = rect.y_offset;
}
static int EncodeFrame(const WebPConfig* const config,
WebPPicture* const sub_image,
WebPData* const encoded_data) {
int ok = 0;
WebPMemoryWriter memory;
if (!config->lossless) {
// We need to call BGRA variant because of the way we do Remap(). Note
// that 'sub_image' will no longer be a view and own some memory.
if (!WebPPictureImportBGRA(
sub_image, (uint8_t*)sub_image->argb,
sub_image->argb_stride * sizeof(*sub_image->argb))) {
goto End;
if (is_first_frame || WebPUtilIsKeyFrame(curr, &rect, prev_canvas)) {
// Add this as a key frame.
if (!WebPFrameCacheAddFrame(cache, config, NULL, NULL, info, sub_image)) {
return 0;
}
sub_image->use_argb = 0;
// Update prev_canvas by simply copying from 'curr'.
WebPUtilCopyPixels(curr, prev_canvas);
} else {
sub_image->use_argb = 1;
if (!WebPFrameCacheShouldTryKeyFrame(cache)) {
// Add this as a frame rectangle.
if (!WebPFrameCacheAddFrame(cache, config, info, sub_image, NULL, NULL)) {
return 0;
}
// Update prev_canvas by blending 'curr' into it.
WebPUtilBlendPixels(curr, gif_rect, prev_canvas);
} else {
WebPPicture full_image;
WebPMuxFrameInfo full_image_info;
int ok;
// Convert to a key frame.
WebPUtilCopyPixels(curr, curr_canvas);
WebPUtilConvertToKeyFrame(prev_canvas, &rect, curr_canvas);
if (!WebPPictureView(curr_canvas, rect.x_offset, rect.y_offset,
rect.width, rect.height, &full_image)) {
return 0;
}
full_image_info = *info;
full_image_info.x_offset = rect.x_offset;
full_image_info.y_offset = rect.y_offset;
// Add both variants to cache: frame rectangle and key frame.
ok = WebPFrameCacheAddFrame(cache, config, info, sub_image,
&full_image_info, &full_image);
WebPPictureFree(&full_image);
if (!ok) return 0;
// Update prev_canvas by simply copying from 'curr_canvas'.
WebPUtilCopyPixels(curr_canvas, prev_canvas);
}
}
sub_image->writer = WebPMemoryWrite;
sub_image->custom_ptr = &memory;
WebPMemoryWriterInit(&memory);
if (!WebPEncode(config, sub_image)) goto End;
encoded_data->bytes = memory.mem;
encoded_data->size = memory.size;
ok = 1;
End:
return ok;
return 1;
}
static void DisposeFrame(WebPMuxAnimDispose dispose_method,
const WebPFrameRect* const gif_rect,
WebPPicture* const frame, WebPPicture* const canvas) {
if (dispose_method == WEBP_MUX_DISPOSE_BACKGROUND) {
ClearPicture(frame, NULL);
ClearPicture(canvas, gif_rect);
WebPUtilClearPic(frame, NULL);
WebPUtilClearPic(canvas, gif_rect);
}
}
static int GetBackgroundColor(const ColorMapObject* const color_map,
GifWord bgcolor_idx, uint32_t* const bgcolor) {
if (kParams.transparent_index != -1 &&
bgcolor_idx == kParams.transparent_index) {
if (transparent_index != -1 && bgcolor_idx == transparent_index) {
*bgcolor = TRANSPARENT_COLOR; // Special case.
return 1;
} else if (color_map == NULL || color_map->Colors == NULL
@ -389,6 +270,7 @@ static void Help(void) {
printf(" -lossy ................. Encode image using lossy compression.\n");
printf(" -q <float> ............. quality factor (0:small..100:big)\n");
printf(" -m <int> ............... compression method (0=fast, 6=slowest)\n");
printf(" -kmin <int> ............ Min distance between key frames\n");
printf(" -kmax <int> ............ Max distance between key frames\n");
printf(" -f <int> ............... filter strength (0=off..100)\n");
printf("\n");
@ -408,33 +290,31 @@ int main(int argc, const char *argv[]) {
const char *in_file = NULL, *out_file = NULL;
FILE* out = NULL;
GifFileType* gif = NULL;
WebPPicture current;
WebPPicture previous;
WebPConfig config;
WebPPicture curr_frame;
WebPPicture prev_canvas;
WebPPicture curr_canvas;
WebPMuxFrameInfo frame;
WebPMuxAnimParams anim = { WHITE_COLOR, 0 };
WebPFrameCache* cache = NULL;
int done;
int c;
int quiet = 0;
WebPConfig config;
WebPMux* mux = NULL;
WebPData webp_data = { NULL, 0 };
int stored_icc = 0; // Whether we have already stored an ICC profile.
int stored_xmp = 0;
// Initialize global variables.
kParams.transparent_index = -1; // No transparency by default.
kParams.is_first_frame = 1;
kParams.key_frame_interval = 9;
kParams.count_since_key_frame = 0;
size_t kmin = 9;
size_t kmax = 17;
memset(&frame, 0, sizeof(frame));
frame.id = WEBP_CHUNK_ANMF;
frame.dispose_method = WEBP_MUX_DISPOSE_BACKGROUND;
frame.blend_method = WEBP_MUX_BLEND;
if (!WebPConfigInit(&config) ||
!WebPPictureInit(&current) || !WebPPictureInit(&previous)) {
if (!WebPConfigInit(&config) || !WebPPictureInit(&curr_frame) ||
!WebPPictureInit(&prev_canvas) || !WebPPictureInit(&curr_canvas)) {
fprintf(stderr, "Error! Version mismatch!\n");
return -1;
}
@ -458,8 +338,9 @@ int main(int argc, const char *argv[]) {
} else if (!strcmp(argv[c], "-m") && c < argc - 1) {
config.method = strtol(argv[++c], NULL, 0);
} else if (!strcmp(argv[c], "-kmax") && c < argc - 1) {
kParams.key_frame_interval = strtoul(argv[++c], NULL, 0);
if (kParams.key_frame_interval == 0) kParams.key_frame_interval = ~0;
kmax = strtoul(argv[++c], NULL, 0);
} else if (!strcmp(argv[c], "-kmin") && c < argc - 1) {
kmin = strtoul(argv[++c], NULL, 0);
} else if (!strcmp(argv[c], "-f") && c < argc - 1) {
config.filter_strength = strtol(argv[++c], NULL, 0);
} else if (!strcmp(argv[c], "-version")) {
@ -482,6 +363,12 @@ int main(int argc, const char *argv[]) {
in_file = argv[c];
}
}
SanitizeKeyFrameIntervals(&kmin, &kmax);
cache = WebPFrameCacheNew(kmin, kmax);
if (cache == NULL) goto End;
if (!WebPValidateConfig(&config)) {
fprintf(stderr, "Error! Invalid configuration.\n");
goto End;
@ -503,11 +390,12 @@ int main(int argc, const char *argv[]) {
if (gif == NULL) goto End;
// Allocate current buffer
current.width = gif->SWidth;
current.height = gif->SHeight;
current.use_argb = 1;
if (!WebPPictureAlloc(&current)) goto End;
if (!WebPPictureCopy(&current, &previous)) goto End;
curr_frame.width = gif->SWidth;
curr_frame.height = gif->SHeight;
curr_frame.use_argb = 1;
if (!WebPPictureAlloc(&curr_frame)) goto End;
if (!WebPPictureCopy(&curr_frame, &prev_canvas)) goto End;
if (!WebPPictureCopy(&curr_frame, &curr_canvas)) goto End;
mux = WebPMuxNew();
if (mux == NULL) {
@ -527,41 +415,28 @@ int main(int argc, const char *argv[]) {
WebPFrameRect gif_rect;
if (!DGifGetImageDesc(gif)) goto End;
if (!ReadFrame(gif, &gif_rect, &sub_image, &current)) {
if (!ReadFrame(gif, &gif_rect, &sub_image, &curr_frame)) {
goto End;
}
OptimizeFrame(&gif_rect, &current, &previous, &sub_image, &frame);
if (!EncodeFrame(&config, &sub_image, &frame.bitstream)) {
if (!OptimizeAndEncodeFrame(&config, &gif_rect, &curr_frame,
&prev_canvas, &curr_canvas, &sub_image,
&frame, cache)) {
fprintf(stderr, "Error! Cannot encode frame as WebP\n");
fprintf(stderr, "Error code: %d\n", sub_image.error_code);
goto End;
}
WebPPictureFree(&sub_image);
// Now we have all the info about the frame, as a Graphic Control
// Extension Block always appears before the Image Descriptor Block.
// So add the frame to mux.
err = WebPMuxPushFrame(mux, &frame, 1);
err = WebPFrameCacheFlush(cache, verbose, mux);
if (err != WEBP_MUX_OK) {
fprintf(stderr, "ERROR (%s): Could not add animation frame.\n",
ErrorString(err));
goto End;
}
if (verbose) {
printf("Added frame %dx%d (offset:%d,%d duration:%d) ",
sub_image.width, sub_image.height,
frame.x_offset, frame.y_offset,
frame.duration);
printf("dispose:%d blend:%d transparent index:%d\n",
frame.dispose_method, frame.blend_method,
kParams.transparent_index);
}
WebPDataClear(&frame.bitstream);
WebPPictureFree(&sub_image);
kParams.is_first_frame = 0;
DisposeFrame(frame.dispose_method, &gif_rect, &current, &previous);
DisposeFrame(frame.dispose_method, &gif_rect,
&curr_frame, &prev_canvas);
is_first_frame = 0;
break;
}
case EXTENSION_RECORD_TYPE: {
@ -590,16 +465,15 @@ int main(int argc, const char *argv[]) {
(dispose == 2) ? WEBP_MUX_DISPOSE_BACKGROUND
: WEBP_MUX_DISPOSE_NONE;
}
kParams.transparent_index =
(flags & GIF_TRANSPARENT_MASK) ? data[4] : -1;
if (kParams.is_first_frame) {
transparent_index = (flags & GIF_TRANSPARENT_MASK) ? data[4] : -1;
if (is_first_frame) {
if (!GetBackgroundColor(gif->SColorMap, gif->SBackGroundColor,
&anim.bgcolor)) {
fprintf(stderr, "GIF decode warning: invalid background color "
"index. Assuming white background.\n");
}
ClearPicture(&current, NULL);
ClearPicture(&previous, NULL);
WebPUtilClearPic(&curr_frame, NULL);
WebPUtilClearPic(&prev_canvas, NULL);
}
break;
}
@ -704,6 +578,14 @@ int main(int argc, const char *argv[]) {
}
} while (!done);
// Flush any pending frames.
err = WebPFrameCacheFlushAll(cache, verbose, mux);
if (err != WEBP_MUX_OK) {
fprintf(stderr, "ERROR (%s): Could not add animation frame.\n",
ErrorString(err));
goto End;
}
// Finish muxing
err = WebPMuxSetAnimationParams(mux, &anim);
if (err != WEBP_MUX_OK) {
@ -738,8 +620,10 @@ int main(int argc, const char *argv[]) {
End:
WebPDataClear(&webp_data);
WebPMuxDelete(mux);
WebPPictureFree(&current);
WebPPictureFree(&previous);
WebPPictureFree(&curr_frame);
WebPPictureFree(&prev_canvas);
WebPPictureFree(&curr_canvas);
WebPFrameCacheDelete(cache);
if (out != NULL && out_file != NULL) fclose(out);
if (gif_error != GIF_OK) {

360
examples/gif2webp_util.c Normal file
View File

@ -0,0 +1,360 @@
// Copyright 2013 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Helper structs and methods for gif2webp tool.
//
#include <assert.h>
#include <stdio.h>
#include "webp/encode.h"
#include "./gif2webp_util.h"
#define DELTA_INFINITY 1ULL << 32
#define KEYFRAME_NONE -1
//------------------------------------------------------------------------------
// Encoded frame.
// Used to store two candidates of encoded data for an animation frame. One of
// the two will be chosen later.
typedef struct {
WebPMuxFrameInfo sub_frame; // Encoded frame rectangle.
WebPMuxFrameInfo key_frame; // Encoded frame if it was converted to keyframe.
} EncodedFrame;
// Release the data contained by 'encoded_frame'.
static void FrameRelease(EncodedFrame* const encoded_frame) {
WebPDataClear(&encoded_frame->sub_frame.bitstream);
WebPDataClear(&encoded_frame->key_frame.bitstream);
memset(encoded_frame, 0, sizeof(*encoded_frame));
}
//------------------------------------------------------------------------------
// Frame cache.
// Used to store encoded frames that haven't been output yet.
struct WebPFrameCache {
EncodedFrame* encoded_frames; // Array of encoded frames.
size_t size; // Number of allocated data elements.
size_t start; // Start index.
size_t count; // Number of valid data elements.
int flush_count; // If >0, ‘flush_count’ frames starting from
// 'start' are ready to be added to mux.
int64_t best_delta; // min(canvas size - frame size) over the frames.
// Can be negative in certain cases due to
// transparent pixels in a frame.
int keyframe; // Index of selected keyframe relative to 'start'.
size_t kmin; // Min distance between key frames.
size_t kmax; // Max distance between key frames.
size_t count_since_key_frame; // Frames seen since the last key frame.
};
// Reset the counters in the cache struct. Doesn't touch 'cache->encoded_frames'
// and 'cache->size'.
static void CacheReset(WebPFrameCache* const cache) {
cache->start = 0;
cache->count = 0;
cache->flush_count = 0;
cache->best_delta = DELTA_INFINITY;
cache->keyframe = KEYFRAME_NONE;
}
WebPFrameCache* WebPFrameCacheNew(size_t kmin, size_t kmax) {
WebPFrameCache* cache = (WebPFrameCache*)malloc(sizeof(*cache));
if (cache == NULL) return NULL;
CacheReset(cache);
cache->kmin = kmin;
cache->kmax = kmax;
cache->count_since_key_frame = 0;
cache->size = kmax - kmin;
cache->encoded_frames =
(EncodedFrame*)calloc(cache->size, sizeof(*cache->encoded_frames));
if (cache->encoded_frames == NULL) return 0;
return cache;
}
void WebPFrameCacheDelete(WebPFrameCache* const cache) {
if (cache != NULL) {
size_t i;
for (i = 0; i < cache->size; ++i) {
FrameRelease(&cache->encoded_frames[i]);
}
free(cache->encoded_frames);
free(cache);
}
}
static int EncodeFrame(const WebPConfig* const config, WebPPicture* const pic,
WebPData* const encoded_data) {
WebPMemoryWriter memory;
pic->use_argb = 1;
pic->writer = WebPMemoryWrite;
pic->custom_ptr = &memory;
WebPMemoryWriterInit(&memory);
if (!WebPEncode(config, pic)) {
return 0;
}
encoded_data->bytes = memory.mem;
encoded_data->size = memory.size;
return 1;
}
// Returns cached frame at given 'index'.
static EncodedFrame* CacheGetFrame(const WebPFrameCache* const cache,
size_t index) {
assert(cache->start + index < cache->size);
return &cache->encoded_frames[cache->start + index];
}
// Calculate the penalty incurred if we encode given frame as a key frame
// instead of a sub-frame.
static int64_t KeyFramePenalty(const EncodedFrame* const encoded_frame) {
return ((int64_t)encoded_frame->key_frame.bitstream.size -
encoded_frame->sub_frame.bitstream.size);
}
static int SetFrame(const WebPConfig* const config,
const WebPMuxFrameInfo* const info, WebPPicture* const pic,
WebPMuxFrameInfo* const dst) {
*dst = *info;
if (!EncodeFrame(config, pic, &dst->bitstream)) {
return 0;
}
return 1;
}
int WebPFrameCacheAddFrame(WebPFrameCache* const cache,
const WebPConfig* const config,
const WebPMuxFrameInfo* const sub_frame_info,
WebPPicture* const sub_frame_pic,
const WebPMuxFrameInfo* const key_frame_info,
WebPPicture* const key_frame_pic) {
const size_t index = cache->count;
EncodedFrame* const encoded_frame = CacheGetFrame(cache, index);
assert(index < cache->size);
assert(sub_frame_pic != NULL || key_frame_pic != NULL);
if (sub_frame_pic != NULL && !SetFrame(config, sub_frame_info, sub_frame_pic,
&encoded_frame->sub_frame)) {
return 0;
}
if (key_frame_pic != NULL && !SetFrame(config, key_frame_info, key_frame_pic,
&encoded_frame->key_frame)) {
return 0;
}
++cache->count;
if (sub_frame_pic == NULL && key_frame_pic != NULL) { // Keyframe.
cache->keyframe = index;
cache->flush_count = cache->count;
cache->count_since_key_frame = 0;
} else {
++cache->count_since_key_frame;
if (sub_frame_pic != NULL && key_frame_pic == NULL) { // Non-keyframe.
assert(cache->count_since_key_frame < cache->kmax);
cache->flush_count = cache->count;
} else { // Analyze size difference of the two variants.
const int64_t curr_delta = KeyFramePenalty(encoded_frame);
if (curr_delta <= cache->best_delta) { // Pick this as keyframe.
cache->keyframe = index;
cache->best_delta = curr_delta;
cache->flush_count = cache->count - 1; // We can flush previous frames.
}
if (cache->count_since_key_frame == cache->kmax) {
cache->flush_count = cache->count;
cache->count_since_key_frame = 0;
}
}
}
return 1;
}
WebPMuxError WebPFrameCacheFlush(WebPFrameCache* const cache, int verbose,
WebPMux* const mux) {
while (cache->flush_count > 0) {
WebPMuxFrameInfo* info;
WebPMuxError err;
EncodedFrame* const curr = CacheGetFrame(cache, 0);
// Pick frame or full canvas.
if (cache->keyframe == 0) {
info = &curr->key_frame;
info->blend_method = WEBP_MUX_NO_BLEND;
cache->keyframe = KEYFRAME_NONE;
cache->best_delta = DELTA_INFINITY;
} else {
info = &curr->sub_frame;
info->blend_method = WEBP_MUX_BLEND;
}
// Add to mux.
err = WebPMuxPushFrame(mux, info, 1);
if (err != WEBP_MUX_OK) return err;
if (verbose) {
printf("Added frame. offset:%d,%d duration:%d dispose:%d blend:%d\n",
info->x_offset, info->y_offset, info->duration,
info->dispose_method, info->blend_method);
}
FrameRelease(curr);
++cache->start;
--cache->flush_count;
--cache->count;
if (cache->keyframe != KEYFRAME_NONE) --cache->keyframe;
}
if (cache->count == 0) CacheReset(cache);
return WEBP_MUX_OK;
}
WebPMuxError WebPFrameCacheFlushAll(WebPFrameCache* const cache, int verbose,
WebPMux* const mux) {
cache->flush_count = cache->count; // Force flushing of all frames.
return WebPFrameCacheFlush(cache, verbose, mux);
}
int WebPFrameCacheShouldTryKeyFrame(const WebPFrameCache* const cache) {
return cache->count_since_key_frame >= cache->kmin;
}
//------------------------------------------------------------------------------
// Frame rectangle and related utilities.
static void ClearRectangle(WebPPicture* const picture,
int left, int top, int width, int height) {
int j;
for (j = top; j < top + height; ++j) {
uint32_t* const dst = picture->argb + j * picture->argb_stride;
int i;
for (i = left; i < left + width; ++i) {
dst[i] = TRANSPARENT_COLOR;
}
}
}
// Clear pixels in 'picture' within given 'rect' to transparent color.
void WebPUtilClearPic(WebPPicture* const picture,
const WebPFrameRect* const rect) {
if (rect != NULL) {
ClearRectangle(picture, rect->x_offset, rect->y_offset,
rect->width, rect->height);
} else {
ClearRectangle(picture, 0, 0, picture->width, picture->height);
}
}
// TODO: Also used in picture.c. Move to a common location?
// Copy width x height pixels from 'src' to 'dst' honoring the strides.
static void CopyPlane(const uint8_t* src, int src_stride,
uint8_t* dst, int dst_stride, int width, int height) {
while (height-- > 0) {
memcpy(dst, src, width);
src += src_stride;
dst += dst_stride;
}
}
void WebPUtilCopyPixels(const WebPPicture* const src, WebPPicture* const dst) {
assert(src->width == dst->width && src->height == dst->height);
CopyPlane((uint8_t*)src->argb, 4 * src->argb_stride, (uint8_t*)dst->argb,
4 * dst->argb_stride, 4 * src->width, src->height);
}
void WebPUtilBlendPixels(const WebPPicture* const src,
const WebPFrameRect* const rect,
WebPPicture* const dst) {
int j;
assert(src->width == dst->width && src->height == dst->height);
for (j = rect->y_offset; j < rect->y_offset + rect->height; ++j) {
int i;
for (i = rect->x_offset; i < rect->x_offset + rect->width; ++i) {
const uint32_t src_pixel = src->argb[j * src->argb_stride + i];
const int src_alpha = src_pixel >> 24;
if (src_alpha != 0) {
dst->argb[j * dst->argb_stride + i] = src_pixel;
}
}
}
}
//------------------------------------------------------------------------------
// Key frame related utilities.
int WebPUtilIsKeyFrame(const WebPPicture* const curr,
const WebPFrameRect* const curr_rect,
const WebPPicture* const prev) {
int i, j;
int is_key_frame = 1;
// If previous canvas (with previous frame disposed) is all transparent,
// current frame is a key frame.
for (i = 0; i < prev->width; ++i) {
for (j = 0; j < prev->height; ++j) {
const uint32_t prev_alpha = (prev->argb[j * prev->argb_stride + i]) >> 24;
if (prev_alpha != 0) {
is_key_frame = 0;
break;
}
}
if (!is_key_frame) break;
}
if (is_key_frame) return 1;
// If current frame covers the whole canvas and does not contain any
// transparent pixels that depend on previous canvas, then current frame is
// a key frame.
if (curr_rect->width == curr->width && curr_rect->height == curr->height) {
assert(curr_rect->x_offset == 0 && curr_rect->y_offset == 0);
is_key_frame = 1;
for (j = 0; j < prev->height; ++j) {
for (i = 0; i < prev->width; ++i) {
const uint32_t prev_alpha =
(prev->argb[j * prev->argb_stride + i]) >> 24;
const uint32_t curr_alpha =
(curr->argb[j * curr->argb_stride + i]) >> 24;
if (curr_alpha != 0xff && prev_alpha != 0) {
is_key_frame = 0;
break;
}
}
if (!is_key_frame) break;
}
if (is_key_frame) return 1;
}
return 0;
}
void WebPUtilConvertToKeyFrame(const WebPPicture* const prev,
WebPFrameRect* const rect,
WebPPicture* const curr) {
int j;
assert(curr->width == prev->width && curr->height == prev->height);
// Replace transparent pixels of current canvas with those from previous
// canvas (with previous frame disposed).
for (j = 0; j < curr->height; ++j) {
int i;
for (i = 0; i < curr->width; ++i) {
uint32_t* const curr_pixel = curr->argb + j * curr->argb_stride + i;
const int curr_alpha = *curr_pixel >> 24;
if (curr_alpha == 0) {
*curr_pixel = prev->argb[j * prev->argb_stride + i];
}
}
}
// Frame rectangle now covers the whole canvas.
rect->x_offset = 0;
rect->y_offset = 0;
rect->width = curr->width;
rect->height = curr->height;
}
//------------------------------------------------------------------------------

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// Copyright 2013 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Helper structs and methods for gif2webp tool.
//
// Author: Urvang (urvang@google.com)
#ifndef WEBP_EXAMPLES_GIF2WEBP_UTIL_H_
#define WEBP_EXAMPLES_GIF2WEBP_UTIL_H_
#include <stdlib.h>
#include "webp/mux.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
//------------------------------------------------------------------------------
// Frame cache.
typedef struct WebPFrameCache WebPFrameCache;
// Given the minimum distance between key frames 'kmin' and maximum distance
// between key frames 'kmax', returns an appropriately allocated cache object.
// Use WebPFrameCacheDelete() to deallocate the 'cache'.
WebPFrameCache* WebPFrameCacheNew(size_t kmin, size_t kmax);
// Release all the frame data from 'cache' and free 'cache'.
void WebPFrameCacheDelete(WebPFrameCache* const cache);
// Add encoded frame in the cache. 'sub_frame_info' and 'sub_frame_pic' are used
// to encode the frame rectangle, while 'key_frame_info' and 'key_frame_pic' are
// used to encode the key frame. Either 'sub_frame_pic' (and 'sub_frame_info')
// or 'key_frame_pic' (and 'key_frame_info') can be NULL; in which case the
// corresponding variant will be omitted.
// Returns true on success.
int WebPFrameCacheAddFrame(WebPFrameCache* const cache,
const WebPConfig* const config,
const WebPMuxFrameInfo* const sub_frame_info,
WebPPicture* const sub_frame_pic,
const WebPMuxFrameInfo* const key_frame_info,
WebPPicture* const key_frame_pic);
// Flush the *ready* frames from cache and add them to 'mux'. If 'verbose' is
// true, prints the information about these frames.
WebPMuxError WebPFrameCacheFlush(WebPFrameCache* const cache, int verbose,
WebPMux* const mux);
// Similar to 'WebPFrameCacheFlushFrames()', but flushes *all* the frames.
WebPMuxError WebPFrameCacheFlushAll(WebPFrameCache* const cache, int verbose,
WebPMux* const mux);
// Returns true if subsequent call to WebPFrameCacheAddFrame() should
// incorporate a potential keyframe.
int WebPFrameCacheShouldTryKeyFrame(const WebPFrameCache* const cache);
//------------------------------------------------------------------------------
// Frame rectangle and related utilities.
#define TRANSPARENT_COLOR 0x00ffffff
typedef struct {
int x_offset, y_offset, width, height;
} WebPFrameRect;
struct WebPPicture;
// Clear pixels in 'picture' within given 'rect' to transparent color.
void WebPUtilClearPic(struct WebPPicture* const picture,
const WebPFrameRect* const rect);
// Copy pixels from 'src' to 'dst' honoring strides. 'src' and 'dst' are assumed
// to be already allocated.
void WebPUtilCopyPixels(const struct WebPPicture* const src,
WebPPicture* const dst);
// Given 'src' picture and its frame rectangle 'rect', blend it into 'dst'.
void WebPUtilBlendPixels(const struct WebPPicture* const src,
const WebPFrameRect* const src_rect,
struct WebPPicture* const dst);
//------------------------------------------------------------------------------
// Key frame related.
// Returns true if 'curr' frame with frame rectangle 'curr_rect' is a key frame,
// that is, it can be decoded independently of 'prev' canvas.
int WebPUtilIsKeyFrame(const WebPPicture* const curr,
const WebPFrameRect* const curr_rect,
const WebPPicture* const prev);
// Given 'prev' frame and current frame rectangle 'rect', convert 'curr' frame
// to a key frame.
void WebPUtilConvertToKeyFrame(const WebPPicture* const prev,
WebPFrameRect* const rect,
WebPPicture* const curr);
//------------------------------------------------------------------------------
#if defined(__cplusplus) || defined(c_plusplus)
} // extern "C"
#endif
#endif // WEBP_EXAMPLES_GIF2WEBP_UTIL_H_