/* * 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 */ /** * @file flashsvenc.c * Flash Screen Video encoder * @author Alex Beregszaszi * @author Benjamin Larsson */ /* Bitstream description * The picture is divided into blocks that are zlib-compressed. * * The decoder is fed complete frames, the frameheader contains: * 4bits of block width * 12bits of frame width * 4bits of block height * 12bits of frame height * * Directly after the header are the compressed blocks. The blocks * have their compressed size represented with 16bits in the beginig. * If the size = 0 then the block is unchanged from the previous frame. * All blocks are decompressed until the buffer is consumed. * * Encoding ideas, a basic encoder would just use a fixed block size. * Block sizes can be multipels of 16, from 16 to 256. The blocks don't * 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. */ /* TODO: * Don't reencode the frame in brute force mode if the frame is a dupe. Speed up. * Make the difference check faster. */ #include <stdio.h> #include <stdlib.h> #include <zlib.h> #include "avcodec.h" #include "bitstream.h" #include "bytestream.h" typedef struct FlashSVContext { AVCodecContext *avctx; uint8_t *previous_frame; AVFrame 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; } FlashSVContext; 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; uint8_t *nsptr; uint8_t *npfptr; int diff = 0; for (i = dx+h; i > dx; i--) { nsptr = sptr+(i*stride)+dy*3; npfptr = pfptr+(i*stride)+dy*3; for (j=0 ; j<w*3 ; j++) { diff |=npfptr[j]^nsptr[j]; dptr[j] = nsptr[j]; } dptr += w*3; } if (diff) return 1; return 0; } static int flashsv_encode_init(AVCodecContext *avctx) { FlashSVContext *s = avctx->priv_data; s->avctx = avctx; if ((avctx->width > 4095) || (avctx->height > 4095)) { av_log(avctx, AV_LOG_ERROR, "Input dimensions too large, input must be max 4096x4096 !\n"); return -1; } if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) { return -1; } // Needed if zlib unused or init aborted before deflateInit memset(&(s->zstream), 0, sizeof(z_stream)); s->last_key_frame=0; s->image_width = avctx->width; s->image_height = avctx->height; s->tmpblock = av_mallocz(3*256*256); s->encbuffer = av_mallocz(s->image_width*s->image_height*3); if (!s->tmpblock || !s->encbuffer) { av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); return -1; } return 0; } static int encode_bitstream(FlashSVContext *s, AVFrame *p, uint8_t *buf, int buf_size, int block_width, int block_height, uint8_t *previous_frame, int* I_frame) { PutBitContext pb; int h_blocks, v_blocks, h_part, v_part, i, j; int buf_pos, res; int pred_blocks = 0; init_put_bits(&pb, buf, buf_size*8); put_bits(&pb, 4, (block_width/16)-1); put_bits(&pb, 12, s->image_width); put_bits(&pb, 4, (block_height/16)-1); put_bits(&pb, 12, s->image_height); flush_put_bits(&pb); buf_pos=4; h_blocks = s->image_width / block_width; h_part = s->image_width % block_width; v_blocks = s->image_height / block_height; v_part = s->image_height % block_height; /* loop over all block columns */ for (j = 0; j < v_blocks + (v_part?1:0); j++) { int hp = j*block_height; // horiz position in frame int hs = (j<v_blocks)?block_height:v_part; // size of block /* loop over all block rows */ for (i = 0; i < h_blocks + (h_part?1:0); i++) { int wp = i*block_width; // vert position in frame int ws = (i<h_blocks)?block_width:h_part; // size of block int ret=Z_OK; uint8_t *ptr; ptr = buf+buf_pos; //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, s->image_height-(hp+hs+1), wp, hs, ws, p->linesize[0], previous_frame); if (res || *I_frame) { unsigned long zsize; zsize = 3*block_width*block_height; ret = compress2(ptr+2, &zsize, s->tmpblock, 3*ws*hs, 9); //ret = deflateReset(&(s->zstream)); if (ret != Z_OK) av_log(s->avctx, AV_LOG_ERROR, "error while compressing block %dx%d\n", i, j); bytestream_put_be16(&ptr,(unsigned int)zsize); buf_pos += zsize+2; //av_log(avctx, AV_LOG_ERROR, "buf_pos = %d\n", buf_pos); } else { pred_blocks++; bytestream_put_be16(&ptr,0); buf_pos += 2; } } } if (pred_blocks) *I_frame = 0; else *I_frame = 1; return buf_pos; } static int flashsv_encode_frame(AVCodecContext *avctx, uint8_t *buf, int buf_size, void *data) { FlashSVContext * const s = avctx->priv_data; AVFrame *pict = data; AVFrame * const p = &s->frame; uint8_t *pfptr; int res; int I_frame = 0; int opt_w, opt_h; *p = *pict; /* First frame needs to be a keyframe */ if (avctx->frame_number == 0) { s->previous_frame = av_mallocz(FFABS(p->linesize[0])*s->image_height); if (!s->previous_frame) { av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); return -1; } I_frame = 1; } if (p->linesize[0] < 0) pfptr = s->previous_frame - ((s->image_height-1) * p->linesize[0]); else pfptr = s->previous_frame; /* Check the placement of keyframes */ if (avctx->gop_size > 0) { if (avctx->frame_number >= s->last_key_frame + avctx->gop_size) { I_frame = 1; } } opt_w=4; opt_h=4; if (buf_size < s->image_width*s->image_height*3) { //Conservative upper bound check for compressed data av_log(avctx, AV_LOG_ERROR, "buf_size %d < %d\n", buf_size, s->image_width*s->image_height*3); return -1; } res = encode_bitstream(s, p, buf, buf_size, opt_w*16, opt_h*16, pfptr, &I_frame); //save the current frame if(p->linesize[0] > 0) memcpy(s->previous_frame, p->data[0], s->image_height*p->linesize[0]); else memcpy(s->previous_frame, p->data[0] + p->linesize[0] * (s->image_height-1), s->image_height*FFABS(p->linesize[0])); //mark the frame type so the muxer can mux it correctly if (I_frame) { p->pict_type = FF_I_TYPE; p->key_frame = 1; s->last_key_frame = avctx->frame_number; av_log(avctx, AV_LOG_DEBUG, "Inserting key frame at frame %d\n",avctx->frame_number); } else { p->pict_type = FF_P_TYPE; p->key_frame = 0; } avctx->coded_frame = p; return res; } static int flashsv_encode_end(AVCodecContext *avctx) { FlashSVContext *s = avctx->priv_data; deflateEnd(&(s->zstream)); av_free(s->encbuffer); av_free(s->previous_frame); av_free(s->tmpblock); return 0; } AVCodec flashsv_encoder = { "flashsv", CODEC_TYPE_VIDEO, CODEC_ID_FLASHSV, sizeof(FlashSVContext), flashsv_encode_init, flashsv_encode_frame, flashsv_encode_end, .pix_fmts = (enum PixelFormat[]){PIX_FMT_BGR24, -1}, };