mirror of
https://github.com/webmproject/libwebp.git
synced 2024-11-20 04:18:26 +01:00
361 lines
12 KiB
C
361 lines
12 KiB
C
// 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;
|
||
}
|
||
|
||
//------------------------------------------------------------------------------
|