mirror of
https://gitee.com/openharmony/third_party_ffmpeg
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289 lines
8.8 KiB
C
289 lines
8.8 KiB
C
/*
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* Flash Screen Video encoder
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* Copyright (C) 2004 Alex Beregszaszi
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* Copyright (C) 2006 Benjamin Larsson
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/* Encoding development sponsored by http://fh-campuswien.ac.at */
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/**
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* @file
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* Flash Screen Video encoder
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* @author Alex Beregszaszi
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* @author Benjamin Larsson
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*
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* A description of the bitstream format for Flash Screen Video version 1/2
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* is part of the SWF File Format Specification (version 10), which can be
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* 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.
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* 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
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* block sizes should give a better result than to just use a fixed size.
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*
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* TODO:
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* Don't reencode the frame in brute force mode if the frame is a dupe.
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* Speed up. Make the difference check faster.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <zlib.h>
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#include "avcodec.h"
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#include "put_bits.h"
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#include "bytestream.h"
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typedef struct FlashSVContext {
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AVCodecContext *avctx;
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uint8_t *previous_frame;
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AVFrame frame;
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int image_width, image_height;
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int block_width, block_height;
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uint8_t *tmpblock;
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uint8_t *encbuffer;
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int block_size;
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z_stream zstream;
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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,
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int h, int w, int stride, uint8_t *pfptr)
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{
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int i, j;
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uint8_t *nsptr;
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uint8_t *npfptr;
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int diff = 0;
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for (i = dx + h; i > dx; i--) {
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nsptr = sptr + i * stride + dy * 3;
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npfptr = pfptr + i * stride + dy * 3;
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for (j = 0; j < w * 3; j++) {
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diff |= npfptr[j] ^ nsptr[j];
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dptr[j] = nsptr[j];
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}
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dptr += w * 3;
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}
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if (diff)
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return 1;
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return 0;
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}
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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 4096x4096 !\n");
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return AVERROR_INVALIDDATA;
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}
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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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s->last_key_frame = 0;
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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);
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s->encbuffer = av_mallocz(s->image_width * s->image_height * 3);
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if (!s->tmpblock || !s->encbuffer) {
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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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return 0;
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}
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static int encode_bitstream(FlashSVContext *s, AVFrame *p, uint8_t *buf,
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int buf_size, int block_width, int block_height,
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uint8_t *previous_frame, int *I_frame)
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{
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PutBitContext pb;
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int h_blocks, v_blocks, h_part, v_part, i, j;
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int buf_pos, res;
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int pred_blocks = 0;
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init_put_bits(&pb, buf, buf_size * 8);
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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);
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flush_put_bits(&pb);
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buf_pos = 4;
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h_blocks = s->image_width / block_width;
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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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int y_pos = j * block_height; // vertical position in frame
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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
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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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/* copy the block to the temp buffer before compression
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* (if it differs from the previous frame's block) */
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res = copy_region_enc(p->data[0], s->tmpblock,
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s->image_height - (y_pos + cur_blk_height + 1),
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x_pos, cur_blk_height, cur_blk_width,
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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,
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3 * cur_blk_width * cur_blk_height, 9);
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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,
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"error while compressing block %dx%d\n", i, j);
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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 {
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pred_blocks++;
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bytestream_put_be16(&ptr, 0);
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buf_pos += 2;
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}
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}
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}
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if (pred_blocks)
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*I_frame = 0;
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else
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*I_frame = 1;
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return buf_pos;
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}
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static int flashsv_encode_frame(AVCodecContext *avctx, uint8_t *buf,
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int buf_size, void *data)
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{
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FlashSVContext * const s = avctx->priv_data;
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AVFrame *pict = data;
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AVFrame * const p = &s->frame;
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uint8_t *pfptr;
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int res;
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int I_frame = 0;
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int opt_w = 4, opt_h = 4;
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*p = *pict;
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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) {
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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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I_frame = 1;
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}
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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
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pfptr = s->previous_frame;
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/* Check the placement of keyframes */
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if (avctx->gop_size > 0 &&
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avctx->frame_number >= s->last_key_frame + avctx->gop_size) {
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I_frame = 1;
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}
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if (buf_size < s->image_width * s->image_height * 3) {
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//Conservative upper bound check for compressed data
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av_log(avctx, AV_LOG_ERROR, "buf_size %d < %d\n",
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buf_size, s->image_width * s->image_height * 3);
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return -1;
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}
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res = encode_bitstream(s, p, buf, buf_size, opt_w * 16, opt_h * 16,
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pfptr, &I_frame);
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//save the current frame
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if (p->linesize[0] > 0)
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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,
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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
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if (I_frame) {
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p->pict_type = AV_PICTURE_TYPE_I;
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p->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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p->pict_type = AV_PICTURE_TYPE_P;
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p->key_frame = 0;
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}
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avctx->coded_frame = p;
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return res;
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}
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static av_cold int flashsv_encode_end(AVCodecContext *avctx)
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{
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FlashSVContext *s = avctx->priv_data;
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deflateEnd(&s->zstream);
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av_free(s->encbuffer);
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av_free(s->previous_frame);
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av_free(s->tmpblock);
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return 0;
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}
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AVCodec ff_flashsv_encoder = {
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.name = "flashsv",
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.type = AVMEDIA_TYPE_VIDEO,
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.id = CODEC_ID_FLASHSV,
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.priv_data_size = sizeof(FlashSVContext),
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.init = flashsv_encode_init,
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.encode = flashsv_encode_frame,
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.close = flashsv_encode_end,
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.pix_fmts = (const enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_NONE},
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.long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video"),
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};
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