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/*
* Flash Screen Video encoder
* Copyright (C) 2004 Alex Beregszaszi
* Copyright (C) 2006 Benjamin Larsson
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* Encoding development sponsored by http://fh-campuswien.ac.at */
/** |
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* @file |
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* Flash Screen Video encoder
* @author Alex Beregszaszi
* @author Benjamin Larsson |
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*
* A description of the bitstream format for Flash Screen Video version 1/2
* is part of the SWF File Format Specification (version 10), which can be
* downloaded from http://www.adobe.com/devnet/swf.html. |
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*/
|
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/* |
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* Encoding ideas: A basic encoder would just use a fixed block size.
* Block sizes can be multiples of 16, from 16 to 256. The blocks don't |
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* have to be quadratic. A brute force search with a set of different
* block sizes should give a better result than to just use a fixed size. |
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*
* TODO:
* Don't reencode the frame in brute force mode if the frame is a dupe.
* Speed up. Make the difference check faster. |
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*/
#include <stdio.h>
#include <stdlib.h>
#include <zlib.h>
#include "avcodec.h" |
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#include "internal.h" |
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#include "put_bits.h" |
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#include "bytestream.h"
typedef struct FlashSVContext {
AVCodecContext *avctx; |
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uint8_t *previous_frame;
int image_width, image_height;
int block_width, block_height;
uint8_t *tmpblock;
uint8_t *encbuffer;
int block_size;
z_stream zstream;
int last_key_frame; |
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} FlashSVContext;
|
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static int copy_region_enc(uint8_t *sptr, uint8_t *dptr, int dx, int dy,
int h, int w, int stride, uint8_t *pfptr)
{
int i, j; |
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uint8_t *nsptr;
uint8_t *npfptr;
int diff = 0;
|
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for (i = dx + h; i > dx; i--) { |
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nsptr = sptr + i * stride + dy * 3;
npfptr = pfptr + i * stride + dy * 3; |
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for (j = 0; j < w * 3; j++) {
diff |= npfptr[j] ^ nsptr[j];
dptr[j] = nsptr[j]; |
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} |
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dptr += w * 3; |
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}
if (diff)
return 1;
return 0;
}
|
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static av_cold int flashsv_encode_end(AVCodecContext *avctx)
{
FlashSVContext *s = avctx->priv_data;
deflateEnd(&s->zstream);
|
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av_freep(&s->encbuffer);
av_freep(&s->previous_frame);
av_freep(&s->tmpblock); |
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av_frame_free(&avctx->coded_frame);
return 0;
}
|
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static av_cold int flashsv_encode_init(AVCodecContext *avctx) |
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{ |
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FlashSVContext *s = avctx->priv_data; |
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s->avctx = avctx;
|
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if (avctx->width > 4095 || avctx->height > 4095) { |
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av_log(avctx, AV_LOG_ERROR, |
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"Input dimensions too large, input must be max 4095x4095 !\n"); |
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return AVERROR_INVALIDDATA; |
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}
// Needed if zlib unused or init aborted before deflateInit |
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memset(&s->zstream, 0, sizeof(z_stream)); |
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|
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s->last_key_frame = 0; |
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|
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s->image_width = avctx->width; |
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s->image_height = avctx->height;
|
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s->tmpblock = av_mallocz(3 * 256 * 256);
s->encbuffer = av_mallocz(s->image_width * s->image_height * 3); |
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if (!s->tmpblock || !s->encbuffer) {
av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); |
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return AVERROR(ENOMEM); |
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}
|
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avctx->coded_frame = av_frame_alloc();
if (!avctx->coded_frame) {
flashsv_encode_end(avctx);
return AVERROR(ENOMEM);
}
|
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return 0;
}
|
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static int encode_bitstream(FlashSVContext *s, const AVFrame *p, uint8_t *buf, |
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int buf_size, int block_width, int block_height,
uint8_t *previous_frame, int *I_frame)
{ |
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PutBitContext pb;
int h_blocks, v_blocks, h_part, v_part, i, j;
int buf_pos, res;
int pred_blocks = 0;
|
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init_put_bits(&pb, buf, buf_size); |
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|
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put_bits(&pb, 4, block_width / 16 - 1); |
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put_bits(&pb, 12, s->image_width); |
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put_bits(&pb, 4, block_height / 16 - 1); |
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put_bits(&pb, 12, s->image_height);
flush_put_bits(&pb); |
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buf_pos = 4; |
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|
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h_blocks = s->image_width / block_width;
h_part = s->image_width % block_width; |
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v_blocks = s->image_height / block_height; |
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v_part = s->image_height % block_height; |
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/* loop over all block columns */ |
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for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) { |
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|
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int y_pos = j * block_height; // vertical position in frame
int cur_blk_height = (j < v_blocks) ? block_height : v_part; |
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/* loop over all block rows */ |
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for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) { |
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int x_pos = i * block_width; // horizontal position in frame
int cur_blk_width = (i < h_blocks) ? block_width : h_part; |
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int ret = Z_OK; |
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uint8_t *ptr = buf + buf_pos; |
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|
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/* copy the block to the temp buffer before compression
* (if it differs from the previous frame's block) */
res = copy_region_enc(p->data[0], s->tmpblock, |
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s->image_height - (y_pos + cur_blk_height + 1),
x_pos, cur_blk_height, cur_blk_width,
p->linesize[0], previous_frame); |
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if (res || *I_frame) { |
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unsigned long zsize = 3 * block_width * block_height; |
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ret = compress2(ptr + 2, &zsize, s->tmpblock,
3 * cur_blk_width * cur_blk_height, 9); |
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|
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//ret = deflateReset(&s->zstream); |
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if (ret != Z_OK) |
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av_log(s->avctx, AV_LOG_ERROR,
"error while compressing block %dx%d\n", i, j); |
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|
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bytestream_put_be16(&ptr, zsize); |
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buf_pos += zsize + 2; |
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av_dlog(s->avctx, "buf_pos = %d\n", buf_pos); |
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} else {
pred_blocks++; |
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bytestream_put_be16(&ptr, 0); |
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buf_pos += 2; |
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}
}
}
if (pred_blocks)
*I_frame = 0;
else
*I_frame = 1;
return buf_pos;
}
|
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static int flashsv_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
const AVFrame *pict, int *got_packet) |
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{ |
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FlashSVContext * const s = avctx->priv_data; |
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const AVFrame * const p = pict; |
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uint8_t *pfptr; |
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int res;
int I_frame = 0; |
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int opt_w = 4, opt_h = 4; |
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|
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/* First frame needs to be a keyframe */ |
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if (avctx->frame_number == 0) { |
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s->previous_frame = av_mallocz(FFABS(p->linesize[0]) * s->image_height); |
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if (!s->previous_frame) {
av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); |
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return AVERROR(ENOMEM); |
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}
I_frame = 1;
}
|
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if (p->linesize[0] < 0) |
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pfptr = s->previous_frame - (s->image_height - 1) * p->linesize[0]; |
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else
pfptr = s->previous_frame;
|
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/* Check the placement of keyframes */ |
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if (avctx->gop_size > 0 &&
avctx->frame_number >= s->last_key_frame + avctx->gop_size) {
I_frame = 1; |
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}
|
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if ((res = ff_alloc_packet2(avctx, pkt, s->image_width * s->image_height * 3)) < 0) |
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return res; |
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|
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pkt->size = encode_bitstream(s, p, pkt->data, pkt->size, opt_w * 16, opt_h * 16,
pfptr, &I_frame); |
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|
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//save the current frame |
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if (p->linesize[0] > 0)
memcpy(s->previous_frame, p->data[0], s->image_height * p->linesize[0]); |
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else |
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memcpy(s->previous_frame,
p->data[0] + p->linesize[0] * (s->image_height - 1), |
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s->image_height * FFABS(p->linesize[0])); |
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//mark the frame type so the muxer can mux it correctly
if (I_frame) { |
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avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
avctx->coded_frame->key_frame = 1; |
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s->last_key_frame = avctx->frame_number; |
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av_dlog(avctx, "Inserting keyframe at frame %d\n", avctx->frame_number); |
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} else { |
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avctx->coded_frame->pict_type = AV_PICTURE_TYPE_P;
avctx->coded_frame->key_frame = 0; |
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}
|
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if (avctx->coded_frame->key_frame) |
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pkt->flags |= AV_PKT_FLAG_KEY;
*got_packet = 1;
return 0; |
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}
|
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AVCodec ff_flashsv_encoder = { |
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.name = "flashsv", |
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.long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video"), |
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.type = AVMEDIA_TYPE_VIDEO, |
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.id = AV_CODEC_ID_FLASHSV, |
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.priv_data_size = sizeof(FlashSVContext),
.init = flashsv_encode_init, |
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.encode2 = flashsv_encode_frame, |
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.close = flashsv_encode_end, |
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.pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_BGR24, AV_PIX_FMT_NONE }, |
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}; |