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gif2webp: Support GIF_DISPOSE_RESTORE_PREVIOUS

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Tweaked the gif2webp_util API to support this.

Requested in: https://code.google.com/p/webp/issues/detail?id=144

Change-Id: I0e8c4edc39227355cd8d3acc55795186e25d0c3a
This commit is contained in:
Urvang Joshi 2014-10-22 17:02:07 -07:00
parent e4c829efe9
commit 65e5eb8a62
3 changed files with 125 additions and 106 deletions
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52
examples/gif2webp.c
View File

@ -46,18 +46,7 @@
//------------------------------------------------------------------------------
static int transparent_index; // Index of transparent color in the map.
static void ResetFrameInfo(WebPMuxFrameInfo* const info) {
WebPDataInit(&info->bitstream);
info->x_offset = 0;
info->y_offset = 0;
info->duration = 0;
info->id = WEBP_CHUNK_ANMF;
info->dispose_method = WEBP_MUX_DISPOSE_NONE;
info->blend_method = WEBP_MUX_BLEND;
transparent_index = -1; // Opaque frame by default.
}
static int transparent_index = -1; // Opaque frame by default.
static void SanitizeKeyFrameIntervals(size_t* const kmin_ptr,
size_t* const kmax_ptr) {
@ -270,7 +259,8 @@ int main(int argc, const char *argv[]) {
GifFileType* gif = NULL;
WebPConfig config;
WebPPicture frame;
WebPMuxFrameInfo info;
int duration = 0;
FrameDisposeMethod orig_dispose = FRAME_DISPOSE_NONE;
WebPMuxAnimParams anim = { WHITE_COLOR, 0 };
WebPFrameCache* cache = NULL;
@ -290,8 +280,6 @@ int main(int argc, const char *argv[]) {
size_t kmax = 0;
int allow_mixed = 0; // If true, each frame can be lossy or lossless.
ResetFrameInfo(&info);
if (!WebPConfigInit(&config) || !WebPPictureInit(&frame)) {
fprintf(stderr, "Error! Version mismatch!\n");
return -1;
@ -497,7 +485,8 @@ int main(int argc, const char *argv[]) {
goto End;
}
if (!WebPFrameCacheAddFrame(cache, &config, &gif_rect, &frame, &info)) {
if (!WebPFrameCacheAddFrame(cache, &config, &gif_rect, orig_dispose,
duration, &frame)) {
fprintf(stderr, "Error! Cannot encode frame as WebP\n");
fprintf(stderr, "Error code: %d\n", frame.error_code);
}
@ -513,7 +502,9 @@ int main(int argc, const char *argv[]) {
// In GIF, graphic control extensions are optional for a frame, so we
// may not get one before reading the next frame. To handle this case,
// we reset frame properties to reasonable defaults for the next frame.
ResetFrameInfo(&info);
orig_dispose = FRAME_DISPOSE_NONE;
duration = 0;
transparent_index = -1; // Opaque frame by default.
break;
}
case EXTENSION_RECORD_TYPE: {
@ -531,20 +522,19 @@ int main(int argc, const char *argv[]) {
const int dispose = (flags >> GIF_DISPOSE_SHIFT) & GIF_DISPOSE_MASK;
const int delay = data[2] | (data[3] << 8); // In 10 ms units.
if (data[0] != 4) goto End;
info.duration = delay * 10; // Duration is in 1 ms units for WebP.
if (dispose == 3) {
static int warning_printed = 0;
if (!warning_printed) {
fprintf(stderr, "WARNING: GIF_DISPOSE_RESTORE unsupported.\n");
warning_printed = 1;
}
// failsafe. TODO(urvang): emulate the correct behaviour by
// recoding the whole frame.
info.dispose_method = WEBP_MUX_DISPOSE_BACKGROUND;
} else {
info.dispose_method =
(dispose == 2) ? WEBP_MUX_DISPOSE_BACKGROUND
: WEBP_MUX_DISPOSE_NONE;
duration = delay * 10; // Duration is in 1 ms units for WebP.
switch (dispose) {
case 3:
orig_dispose = FRAME_DISPOSE_RESTORE_PREVIOUS;
break;
case 2:
orig_dispose = FRAME_DISPOSE_BACKGROUND;
break;
case 1:
case 0:
default:
orig_dispose = FRAME_DISPOSE_NONE;
break;
}
transparent_index = (flags & GIF_TRANSPARENT_MASK) ? data[4] : -1;
break;

160
examples/gif2webp_util.c
View File

@ -13,6 +13,7 @@
#include <assert.h>
#include <stdio.h>
#include "utils/utils.h"
#include "webp/encode.h"
#include "./gif2webp_util.h"
@ -293,14 +294,17 @@ struct WebPFrameCache {
WebPFrameRect prev_orig_rect; // Previous input (e.g. GIF) frame rectangle.
WebPFrameRect prev_webp_rect; // Previous WebP frame rectangle.
WebPMuxAnimDispose prev_orig_dispose; // Previous input dispose method.
FrameDisposeMethod prev_orig_dispose; // Previous input dispose method.
int prev_candidate_undecided; // True if sub-frame vs keyframe decision
// hasn't been made for the previous frame yet.
WebPPicture prev_canvas; // Previous canvas (NOT disposed).
WebPPicture curr_canvas; // Current canvas (NOT disposed).
WebPPicture curr_canvas; // Current canvas (NOT disposed).
WebPPicture curr_canvas_tmp; // Temporary storage for current canvas.
WebPPicture prev_canvas; // Previous canvas (NOT disposed).
WebPPicture prev_canvas_disposed; // Previous canvas disposed to background.
WebPPicture curr_canvas_tmp; // Temporary storage for current canvas.
WebPPicture prev_to_prev_canvas_disposed; // Previous to previous canvas
// (disposed as per its original
// dispose method).
int is_first_frame; // True if no frames have been added to the cache
// since WebPFrameCacheNew().
};
@ -317,7 +321,7 @@ static void CacheReset(WebPFrameCache* const cache) {
WebPFrameCache* WebPFrameCacheNew(int width, int height,
size_t kmin, size_t kmax, int allow_mixed) {
WebPFrameCache* cache = (WebPFrameCache*)malloc(sizeof(*cache));
WebPFrameCache* cache = (WebPFrameCache*)WebPSafeCalloc(1, sizeof(*cache));
if (cache == NULL) return NULL;
CacheReset(cache);
// sanity init, so we can call WebPFrameCacheDelete():
@ -327,22 +331,27 @@ WebPFrameCache* WebPFrameCacheNew(int width, int height,
cache->is_first_frame = 1;
// Picture buffers.
if (!WebPPictureInit(&cache->prev_canvas) ||
!WebPPictureInit(&cache->curr_canvas) ||
if (!WebPPictureInit(&cache->curr_canvas) ||
!WebPPictureInit(&cache->curr_canvas_tmp) ||
!WebPPictureInit(&cache->prev_canvas) ||
!WebPPictureInit(&cache->prev_canvas_disposed) ||
!WebPPictureInit(&cache->curr_canvas_tmp)) {
!WebPPictureInit(&cache->prev_to_prev_canvas_disposed)) {
return NULL;
}
cache->prev_canvas.width = width;
cache->prev_canvas.height = height;
cache->prev_canvas.use_argb = 1;
if (!WebPPictureAlloc(&cache->prev_canvas) ||
!WebPPictureCopy(&cache->prev_canvas, &cache->curr_canvas) ||
!WebPPictureCopy(&cache->prev_canvas, &cache->prev_canvas_disposed) ||
!WebPPictureCopy(&cache->prev_canvas, &cache->curr_canvas_tmp)) {
cache->curr_canvas.width = width;
cache->curr_canvas.height = height;
cache->curr_canvas.use_argb = 1;
if (!WebPPictureAlloc(&cache->curr_canvas) ||
!WebPPictureCopy(&cache->curr_canvas, &cache->curr_canvas_tmp) ||
!WebPPictureCopy(&cache->curr_canvas, &cache->prev_canvas) ||
!WebPPictureCopy(&cache->curr_canvas, &cache->prev_canvas_disposed) ||
!WebPPictureCopy(&cache->curr_canvas,
&cache->prev_to_prev_canvas_disposed)) {
goto Err;
}
WebPUtilClearPic(&cache->prev_canvas, NULL);
WebPUtilClearPic(&cache->prev_canvas_disposed, NULL);
WebPUtilClearPic(&cache->prev_to_prev_canvas_disposed, NULL);
// Cache data.
cache->allow_mixed = allow_mixed;
@ -351,8 +360,8 @@ WebPFrameCache* WebPFrameCacheNew(int width, int height,
cache->count_since_key_frame = 0;
assert(kmax > kmin);
cache->size = kmax - kmin + 1; // One extra storage for previous frame.
cache->encoded_frames =
(EncodedFrame*)calloc(cache->size, sizeof(*cache->encoded_frames));
cache->encoded_frames = (EncodedFrame*)WebPSafeCalloc(
cache->size, sizeof(*cache->encoded_frames));
if (cache->encoded_frames == NULL) goto Err;
return cache; // All OK.
@ -369,13 +378,14 @@ void WebPFrameCacheDelete(WebPFrameCache* const cache) {
for (i = 0; i < cache->size; ++i) {
FrameRelease(&cache->encoded_frames[i]);
}
free(cache->encoded_frames);
WebPSafeFree(cache->encoded_frames);
}
WebPPictureFree(&cache->prev_canvas);
WebPPictureFree(&cache->curr_canvas);
WebPPictureFree(&cache->prev_canvas_disposed);
WebPPictureFree(&cache->curr_canvas_tmp);
free(cache);
WebPPictureFree(&cache->prev_canvas);
WebPPictureFree(&cache->prev_canvas_disposed);
WebPPictureFree(&cache->prev_to_prev_canvas_disposed);
WebPSafeFree(cache);
}
}
@ -451,18 +461,23 @@ static int GetColorCount(const WebPPicture* const pic) {
#undef HASH_SIZE
#undef HASH_RIGHT_SHIFT
static void DisposeFullFrame(WebPMuxAnimDispose dispose_method,
WebPPicture* const frame) {
if (dispose_method == WEBP_MUX_DISPOSE_BACKGROUND) {
WebPUtilClearPic(frame, NULL);
}
}
static void DisposeFrameRectangle(WebPMuxAnimDispose dispose_method,
const WebPFrameRect* const gif_rect,
WebPPicture* const frame) {
if (dispose_method == WEBP_MUX_DISPOSE_BACKGROUND) {
WebPUtilClearPic(frame, gif_rect);
static void DisposeFrameRectangle(int dispose_method,
const WebPFrameRect* const rect,
const WebPPicture* const prev_canvas,
WebPPicture* const curr_canvas) {
assert(rect != NULL);
if (dispose_method == FRAME_DISPOSE_BACKGROUND) {
WebPUtilClearPic(curr_canvas, rect);
} else if (dispose_method == FRAME_DISPOSE_RESTORE_PREVIOUS) {
const int src_stride = prev_canvas->argb_stride;
const uint32_t* const src =
prev_canvas->argb + rect->x_offset + rect->y_offset * src_stride;
const int dst_stride = curr_canvas->argb_stride;
uint32_t* const dst =
curr_canvas->argb + rect->x_offset + rect->y_offset * dst_stride;
assert(prev_canvas != NULL);
CopyPlane((uint8_t*)src, 4 * src_stride, (uint8_t*)dst, 4 * dst_stride,
4 * rect->width, rect->height);
}
}
@ -536,9 +551,8 @@ typedef struct {
// Generates a candidate encoded frame given a picture and metadata.
static WebPEncodingError EncodeCandidate(WebPPicture* const sub_frame,
const WebPFrameRect* const rect,
const WebPMuxFrameInfo* const info,
const WebPConfig* const config,
int use_blending,
int use_blending, int duration,
Candidate* const candidate) {
WebPEncodingError error_code = VP8_ENC_OK;
assert(candidate != NULL);
@ -546,11 +560,13 @@ static WebPEncodingError EncodeCandidate(WebPPicture* const sub_frame,
// Set frame rect and info.
candidate->rect = *rect;
candidate->info = *info;
candidate->info.id = WEBP_CHUNK_ANMF;
candidate->info.x_offset = rect->x_offset;
candidate->info.y_offset = rect->y_offset;
candidate->info.dispose_method = WEBP_MUX_DISPOSE_NONE; // Set later.
candidate->info.blend_method =
use_blending ? WEBP_MUX_BLEND : WEBP_MUX_NO_BLEND;
candidate->info.duration = duration;
// Encode picture.
WebPMemoryWriterInit(&candidate->mem);
@ -607,8 +623,7 @@ enum {
static WebPEncodingError GenerateCandidates(
WebPFrameCache* const cache, Candidate candidates[CANDIDATE_COUNT],
WebPMuxAnimDispose dispose_method, int is_lossless, int is_key_frame,
const WebPFrameRect* const rect, WebPPicture* sub_frame,
const WebPMuxFrameInfo* const info,
const WebPFrameRect* const rect, WebPPicture* sub_frame, int duration,
const WebPConfig* const config_ll, const WebPConfig* const config_lossy) {
WebPEncodingError error_code = VP8_ENC_OK;
const int is_dispose_none = (dispose_method == WEBP_MUX_DISPOSE_NONE);
@ -617,10 +632,10 @@ static WebPEncodingError GenerateCandidates(
Candidate* const candidate_lossy = is_dispose_none
? &candidates[LOSSY_DISP_NONE]
: &candidates[LOSSY_DISP_BG];
const WebPPicture* const prev_canvas =
is_dispose_none ? &cache->prev_canvas : &cache->prev_canvas_disposed;
WebPPicture* const curr_canvas = &cache->curr_canvas;
WebPPicture* const curr_canvas_tmp = &cache->curr_canvas_tmp;
const WebPPicture* const prev_canvas =
is_dispose_none ? &cache->prev_canvas : &cache->prev_canvas_disposed;
const int use_blending =
!is_key_frame &&
IsBlendingPossible(prev_canvas, curr_canvas, rect);
@ -643,8 +658,8 @@ static WebPEncodingError GenerateCandidates(
curr_canvas_saved = 1;
IncreaseTransparency(prev_canvas, rect, curr_canvas);
}
error_code = EncodeCandidate(sub_frame, rect, info, config_ll, use_blending,
candidate_ll);
error_code = EncodeCandidate(sub_frame, rect, config_ll, use_blending,
duration, candidate_ll);
if (error_code != VP8_ENC_OK) return error_code;
if (use_blending) {
CopyPixels(curr_canvas_tmp, curr_canvas); // restore
@ -661,8 +676,8 @@ static WebPEncodingError GenerateCandidates(
}
FlattenSimilarBlocks(prev_canvas, rect, curr_canvas);
}
error_code = EncodeCandidate(sub_frame, rect, info, config_lossy,
use_blending, candidate_lossy);
error_code = EncodeCandidate(sub_frame, rect, config_lossy, use_blending,
duration, candidate_lossy);
if (error_code != VP8_ENC_OK) return error_code;
if (!is_key_frame) {
CopyPixels(curr_canvas_tmp, curr_canvas); // restore
@ -722,16 +737,15 @@ static void PickBestCandidate(WebPFrameCache* const cache,
// (lossy/lossless), dispose methods, blending methods etc to encode the current
// frame and outputs the best one in 'encoded_frame'.
static WebPEncodingError SetFrame(WebPFrameCache* const cache,
const WebPConfig* const config,
const WebPMuxFrameInfo* const info,
const WebPConfig* const config, int duration,
const WebPFrameRect* const orig_rect,
int is_key_frame,
EncodedFrame* const encoded_frame) {
int i;
WebPEncodingError error_code = VP8_ENC_OK;
WebPPicture* const curr_canvas = &cache->curr_canvas;
const WebPPicture* const prev_canvas = &cache->prev_canvas;
WebPPicture* const prev_canvas_disposed = &cache->prev_canvas_disposed;
WebPPicture* const curr_canvas = &cache->curr_canvas;
Candidate candidates[CANDIDATE_COUNT];
const int is_lossless = config->lossless;
@ -772,7 +786,7 @@ static WebPEncodingError SetFrame(WebPFrameCache* const cache,
// Change-rectangle assuming previous frame was DISPOSE_BACKGROUND.
CopyPixels(prev_canvas, prev_canvas_disposed);
DisposeFrameRectangle(WEBP_MUX_DISPOSE_BACKGROUND, &cache->prev_webp_rect,
prev_canvas_disposed);
NULL, prev_canvas_disposed);
GetSubRect(prev_canvas_disposed, curr_canvas, orig_rect, is_key_frame,
&rect_bg, &sub_frame_bg);
@ -785,16 +799,17 @@ static WebPEncodingError SetFrame(WebPFrameCache* const cache,
if (try_dispose_none) {
error_code = GenerateCandidates(
cache, candidates, WEBP_MUX_DISPOSE_NONE, is_lossless, is_key_frame,
&rect_none, &sub_frame_none, info, &config_ll, &config_lossy);
&rect_none, &sub_frame_none, duration, &config_ll, &config_lossy);
if (error_code != VP8_ENC_OK) goto Err;
}
if (try_dispose_bg) {
assert(!cache->is_first_frame);
assert(dispose_bg_possible);
error_code = GenerateCandidates(
cache, candidates, WEBP_MUX_DISPOSE_BACKGROUND, is_lossless,
is_key_frame, &rect_bg, &sub_frame_bg, info, &config_ll, &config_lossy);
error_code =
GenerateCandidates(cache, candidates, WEBP_MUX_DISPOSE_BACKGROUND,
is_lossless, is_key_frame, &rect_bg, &sub_frame_bg,
duration, &config_ll, &config_lossy);
if (error_code != VP8_ENC_OK) goto Err;
}
@ -828,19 +843,22 @@ static int64_t KeyFramePenalty(const EncodedFrame* const encoded_frame) {
int WebPFrameCacheAddFrame(WebPFrameCache* const cache,
const WebPConfig* const config,
const WebPFrameRect* const orig_rect_ptr,
WebPPicture* const frame,
WebPMuxFrameInfo* const info) {
FrameDisposeMethod orig_dispose_method,
int duration, WebPPicture* const frame) {
// Initialize.
int ok = 0;
WebPEncodingError error_code = VP8_ENC_OK;
WebPPicture* const prev_canvas = &cache->prev_canvas;
WebPPicture* const curr_canvas = &cache->curr_canvas;
WebPPicture* const prev_canvas = &cache->prev_canvas;
WebPPicture* const prev_to_prev_canvas_disposed =
&cache->prev_to_prev_canvas_disposed;
WebPPicture* const prev_canvas_disposed = &cache->prev_canvas_disposed;
const size_t position = cache->count;
EncodedFrame* const encoded_frame = CacheGetFrame(cache, position);
WebPFrameRect orig_rect;
assert(position < cache->size);
if (frame == NULL || info == NULL) {
if (frame == NULL) {
return 0;
}
@ -867,7 +885,8 @@ int WebPFrameCacheAddFrame(WebPFrameCache* const cache,
CopyPixels(frame, curr_canvas);
// Add this as a key frame.
// Note: we use original rectangle as-is for the first frame.
error_code = SetFrame(cache, config, info, &orig_rect, 1, encoded_frame);
error_code =
SetFrame(cache, config, duration, &orig_rect, 1, encoded_frame);
if (error_code != VP8_ENC_OK) {
goto End;
}
@ -877,19 +896,21 @@ int WebPFrameCacheAddFrame(WebPFrameCache* const cache,
cache->count_since_key_frame = 0;
cache->prev_candidate_undecided = 0;
} else {
// Store previous canvas.
// Store previous to previous and previous canvases.
CopyPixels(prev_canvas_disposed, prev_to_prev_canvas_disposed);
CopyPixels(curr_canvas, prev_canvas);
// Create curr_canvas:
// * Start with disposed previous canvas.
// * Then blend 'frame' onto it.
DisposeFrameRectangle(cache->prev_orig_dispose, &cache->prev_orig_rect,
curr_canvas);
prev_to_prev_canvas_disposed, curr_canvas);
CopyPixels(curr_canvas, prev_canvas_disposed);
BlendPixels(frame, &orig_rect, curr_canvas);
++cache->count_since_key_frame;
if (cache->count_since_key_frame <= cache->kmin) {
// Add this as a frame rectangle.
error_code = SetFrame(cache, config, info, NULL, 0, encoded_frame);
error_code = SetFrame(cache, config, duration, NULL, 0, encoded_frame);
if (error_code != VP8_ENC_OK) {
goto End;
}
@ -897,21 +918,16 @@ int WebPFrameCacheAddFrame(WebPFrameCache* const cache,
cache->flush_count = cache->count - 1;
cache->prev_candidate_undecided = 0;
} else {
WebPMuxFrameInfo full_image_info;
int64_t curr_delta;
// Add frame rectangle to cache.
error_code = SetFrame(cache, config, info, NULL, 0, encoded_frame);
error_code = SetFrame(cache, config, duration, NULL, 0, encoded_frame);
if (error_code != VP8_ENC_OK) {
goto End;
}
// Add key frame to cache, too.
full_image_info = *info;
full_image_info.x_offset = 0;
full_image_info.y_offset = 0;
error_code =
SetFrame(cache, config, &full_image_info, NULL, 1, encoded_frame);
error_code = SetFrame(cache, config, duration, NULL, 1, encoded_frame);
if (error_code != VP8_ENC_OK) goto End;
// Analyze size difference of the two variants.
@ -936,12 +952,18 @@ int WebPFrameCacheAddFrame(WebPFrameCache* const cache,
}
cache->prev_candidate_undecided = 1;
}
// Recalculate prev_canvas_disposed (as it might have been modified).
CopyPixels(prev_canvas, prev_canvas_disposed);
DisposeFrameRectangle(cache->prev_orig_dispose, &cache->prev_orig_rect,
prev_to_prev_canvas_disposed, prev_canvas_disposed);
}
DisposeFullFrame(info->dispose_method, frame);
// Dispose the 'frame'.
DisposeFrameRectangle(orig_dispose_method, &orig_rect, prev_canvas_disposed,
frame);
cache->is_first_frame = 0;
cache->prev_orig_dispose = info->dispose_method;
cache->prev_orig_dispose = orig_dispose_method;
cache->prev_orig_rect = orig_rect;
ok = 1;

19
examples/gif2webp_util.h
View File

@ -29,6 +29,13 @@ extern "C" {
struct WebPPicture;
// Includes all disposal methods, even the ones not supported by WebP bitstream.
typedef enum FrameDisposeMethod {
FRAME_DISPOSE_NONE,
FRAME_DISPOSE_BACKGROUND,
FRAME_DISPOSE_RESTORE_PREVIOUS
} FrameDisposeMethod;
typedef struct {
int x_offset, y_offset, width, height;
} WebPFrameRect;
@ -53,15 +60,15 @@ WebPFrameCache* WebPFrameCacheNew(int width, int height,
// Release all the frame data from 'cache' and free 'cache'.
void WebPFrameCacheDelete(WebPFrameCache* const cache);
// Given an image described by 'frame', 'info' and 'orig_rect', optimize it for
// WebP, encode it and add it to 'cache'. 'orig_rect' can be NULL.
// This takes care of frame disposal too, according to 'info->dispose_method'.
// Given an image described by 'frame', 'rect', 'dispose_method' and 'duration',
// optimize it for WebP, encode it and add it to 'cache'. 'rect' can be NULL.
// This takes care of frame disposal too, according to 'dispose_method'.
// Returns false in case of error (and sets frame->error_code accordingly).
int WebPFrameCacheAddFrame(WebPFrameCache* const cache,
const WebPConfig* const config,
const WebPFrameRect* const orig_rect,
WebPPicture* const frame,
WebPMuxFrameInfo* const info);
const WebPFrameRect* const rect,
FrameDisposeMethod dispose_method, int duration,
WebPPicture* const frame);
// Flush the *ready* frames from cache and add them to 'mux'. If 'verbose' is
// true, prints the information about these frames.