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AnimEncoder API: Optimize single-frame animated images

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Try converting them to a non-animated image and pick that one if it's smaller
in size.

Change-Id: Ib97438fd2a95b1bfa9b7526a0938a9d85df33a57
This commit is contained in:
Urvang Joshi 2015-01-06 16:37:53 -08:00 committed by Gerrit Code Review
parent abbae27982
commit 9e92b6eac6
1 changed files with 113 additions and 12 deletions
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125
src/mux/anim_encode.c
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@ -14,6 +14,7 @@
#include <stdio.h>
#include "../utils/utils.h"
#include "../webp/decode.h"
#include "../webp/format_constants.h"
#include "../webp/mux.h"
@ -38,7 +39,10 @@ struct WebPAnimEncoder {
const int canvas_height_; // Canvas height.
const WebPAnimEncoderOptions options_; // Global encoding options.
FrameRect prev_webp_rect; // Previous WebP frame rectangle.
FrameRect prev_rect; // Previous WebP frame rectangle.
WebPConfig last_config; // Cached in case a re-encode is needed.
WebPConfig last_config2; // 2nd cached config; only valid if
// 'options_.allow_mixed' is true.
WebPPicture* curr_canvas_; // Only pointer; we don't own memory.
@ -789,7 +793,7 @@ static void PickBestCandidate(WebPAnimEncoder* const enc,
: WEBP_MUX_DISPOSE_BACKGROUND;
SetPreviousDisposeMethod(enc, prev_dispose_method);
}
enc->prev_webp_rect = candidates[i].rect_; // save for next frame.
enc->prev_rect = candidates[i].rect_; // save for next frame.
} else {
WebPMemoryWriterClear(&candidates[i].mem_);
candidates[i].evaluate_ = 0;
@ -833,6 +837,8 @@ static WebPEncodingError SetFrame(WebPAnimEncoder* const enc, int duration,
WebPConfig config_lossy = *config;
config_ll.lossless = 1;
config_lossy.lossless = 0;
enc->last_config = *config;
enc->last_config2 = config->lossless ? config_lossy : config_ll;
if (!WebPPictureInit(&sub_frame_none) || !WebPPictureInit(&sub_frame_bg)) {
return VP8_ENC_ERROR_INVALID_CONFIGURATION;
@ -850,7 +856,7 @@ static WebPEncodingError SetFrame(WebPAnimEncoder* const enc, int duration,
// Change-rectangle assuming previous frame was DISPOSE_BACKGROUND.
WebPPicture* const prev_canvas_disposed = &enc->prev_canvas_disposed_;
CopyPixels(prev_canvas, prev_canvas_disposed);
DisposeFrameRectangle(WEBP_MUX_DISPOSE_BACKGROUND, &enc->prev_webp_rect,
DisposeFrameRectangle(WEBP_MUX_DISPOSE_BACKGROUND, &enc->prev_rect,
prev_canvas_disposed);
GetSubRect(prev_canvas_disposed, curr_canvas, is_key_frame, is_first_frame,
&rect_bg, &sub_frame_bg);
@ -1082,10 +1088,105 @@ int WebPAnimEncoderAdd(WebPAnimEncoder* enc, WebPPicture* frame, int duration,
// -----------------------------------------------------------------------------
// Bitstream assembly.
static WebPMuxError OptimizeSingleFrame(WebPMux* const mux) {
// TODO(urvang): If only one frame, re-encode it as a full frame.
(void)mux;
return WEBP_MUX_OK;
static int DecodeFrameOntoCanvas(const WebPMuxFrameInfo* const frame,
WebPPicture* const canvas) {
const WebPData* const image = &frame->bitstream;
WebPPicture sub_image;
WebPDecoderConfig config;
WebPInitDecoderConfig(&config);
WebPUtilClearPic(canvas, NULL);
if (WebPGetFeatures(image->bytes, image->size, &config.input) !=
VP8_STATUS_OK) {
return 0;
}
if (!WebPPictureView(canvas, frame->x_offset, frame->y_offset,
config.input.width, config.input.height, &sub_image)) {
return 0;
}
config.output.is_external_memory = 1;
config.output.colorspace = MODE_BGRA;
config.output.u.RGBA.rgba = (uint8_t*)sub_image.argb;
config.output.u.RGBA.stride = sub_image.argb_stride * 4;
config.output.u.RGBA.size = config.output.u.RGBA.stride * sub_image.height;
if (WebPDecode(image->bytes, image->size, &config) != VP8_STATUS_OK) {
return 0;
}
return 1;
}
static int FrameToFullCanvas(WebPAnimEncoder* const enc,
const WebPMuxFrameInfo* const frame,
WebPData* const full_image) {
WebPPicture* const canvas_buf = &enc->curr_canvas_copy_;
WebPMemoryWriter mem1, mem2;
WebPMemoryWriterInit(&mem1);
WebPMemoryWriterInit(&mem2);
if (!DecodeFrameOntoCanvas(frame, canvas_buf)) goto Err;
if (!EncodeFrame(&enc->last_config, canvas_buf, &mem1)) goto Err;
GetEncodedData(&mem1, full_image);
if (enc->options_.allow_mixed) {
if (!EncodeFrame(&enc->last_config, canvas_buf, &mem2)) goto Err;
if (mem2.size < mem1.size) {
GetEncodedData(&mem2, full_image);
WebPMemoryWriterClear(&mem1);
} else {
WebPMemoryWriterClear(&mem2);
}
}
return 1;
Err:
WebPMemoryWriterClear(&mem1);
WebPMemoryWriterClear(&mem2);
return 0;
}
// Convert a single-frame animation to a non-animated image if appropriate.
// TODO(urvang): Can we pick one of the two heuristically (based on frame
// rectangle and/or presence of alpha)?
static WebPMuxError OptimizeSingleFrame(WebPAnimEncoder* const enc,
WebPData* const webp_data) {
WebPMuxError err = WEBP_MUX_OK;
int canvas_width, canvas_height;
WebPMuxFrameInfo frame;
WebPData full_image;
WebPData webp_data2;
WebPMux* const mux = WebPMuxCreate(webp_data, 0);
if (mux == NULL) return WEBP_MUX_BAD_DATA;
assert(enc->frame_count_ == 1);
WebPDataInit(&frame.bitstream);
WebPDataInit(&full_image);
WebPDataInit(&webp_data2);
err = WebPMuxGetFrame(mux, 1, &frame);
if (err != WEBP_MUX_OK) goto End;
if (frame.id != WEBP_CHUNK_ANMF) goto End; // Non-animation: nothing to do.
err = WebPMuxGetCanvasSize(mux, &canvas_width, &canvas_height);
if (err != WEBP_MUX_OK) goto End;
if (!FrameToFullCanvas(enc, &frame, &full_image)) {
err = WEBP_MUX_BAD_DATA;
goto End;
}
err = WebPMuxSetImage(mux, &full_image, 1);
if (err != WEBP_MUX_OK) goto End;
err = WebPMuxAssemble(mux, &webp_data2);
if (err != WEBP_MUX_OK) goto End;
if (webp_data2.size < webp_data->size) { // Pick 'webp_data2' if smaller.
WebPDataClear(webp_data);
*webp_data = webp_data2;
WebPDataInit(&webp_data2);
}
End:
WebPDataClear(&frame.bitstream);
WebPDataClear(&full_image);
WebPMuxDelete(mux);
WebPDataClear(&webp_data2);
return err;
}
int WebPAnimEncoderAssemble(WebPAnimEncoder* enc, WebPData* webp_data) {
@ -1116,15 +1217,15 @@ int WebPAnimEncoderAssemble(WebPAnimEncoder* enc, WebPData* webp_data) {
err = WebPMuxSetAnimationParams(mux, &enc->options_.anim_params);
if (err != WEBP_MUX_OK) goto Err;
if (enc->frame_count_ == 1) {
err = OptimizeSingleFrame(mux);
if (err != WEBP_MUX_OK) goto Err;
}
// Assemble into a WebP bitstream.
err = WebPMuxAssemble(mux, webp_data);
if (err != WEBP_MUX_OK) goto Err;
if (enc->frame_count_ == 1) {
err = OptimizeSingleFrame(enc, webp_data);
if (err != WEBP_MUX_OK) goto Err;
}
return 1;
Err: