1/* 2 * Flash Screen Video encoder 3 * Copyright (C) 2004 Alex Beregszaszi 4 * Copyright (C) 2006 Benjamin Larsson 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23/* Encoding development sponsored by http://fh-campuswien.ac.at */ 24 25/** 26 * @file libavcodec/flashsvenc.c 27 * Flash Screen Video encoder 28 * @author Alex Beregszaszi 29 * @author Benjamin Larsson 30 */ 31 32/* Bitstream description 33 * The picture is divided into blocks that are zlib-compressed. 34 * 35 * The decoder is fed complete frames, the frameheader contains: 36 * 4bits of block width 37 * 12bits of frame width 38 * 4bits of block height 39 * 12bits of frame height 40 * 41 * Directly after the header are the compressed blocks. The blocks 42 * have their compressed size represented with 16bits in the beginig. 43 * If the size = 0 then the block is unchanged from the previous frame. 44 * All blocks are decompressed until the buffer is consumed. 45 * 46 * Encoding ideas, a basic encoder would just use a fixed block size. 47 * Block sizes can be multipels of 16, from 16 to 256. The blocks don't 48 * have to be quadratic. A brute force search with a set of different 49 * block sizes should give a better result than to just use a fixed size. 50 */ 51 52/* TODO: 53 * Don't reencode the frame in brute force mode if the frame is a dupe. Speed up. 54 * Make the difference check faster. 55 */ 56 57#include <stdio.h> 58#include <stdlib.h> 59#include <zlib.h> 60 61#include "avcodec.h" 62#include "bitstream.h" 63#include "bytestream.h" 64 65 66typedef struct FlashSVContext { 67 AVCodecContext *avctx; 68 uint8_t *previous_frame; 69 AVFrame frame; 70 int image_width, image_height; 71 int block_width, block_height; 72 uint8_t* tmpblock; 73 uint8_t* encbuffer; 74 int block_size; 75 z_stream zstream; 76 int last_key_frame; 77} FlashSVContext; 78 79static int copy_region_enc(uint8_t *sptr, uint8_t *dptr, 80 int dx, int dy, int h, int w, int stride, uint8_t *pfptr) { 81 int i,j; 82 uint8_t *nsptr; 83 uint8_t *npfptr; 84 int diff = 0; 85 86 for (i = dx+h; i > dx; i--) { 87 nsptr = sptr+(i*stride)+dy*3; 88 npfptr = pfptr+(i*stride)+dy*3; 89 for (j=0 ; j<w*3 ; j++) { 90 diff |=npfptr[j]^nsptr[j]; 91 dptr[j] = nsptr[j]; 92 } 93 dptr += w*3; 94 } 95 if (diff) 96 return 1; 97 return 0; 98} 99 100static av_cold int flashsv_encode_init(AVCodecContext *avctx) 101{ 102 FlashSVContext *s = avctx->priv_data; 103 104 s->avctx = avctx; 105 106 if ((avctx->width > 4095) || (avctx->height > 4095)) { 107 av_log(avctx, AV_LOG_ERROR, "Input dimensions too large, input must be max 4096x4096 !\n"); 108 return -1; 109 } 110 111 if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) { 112 return -1; 113 } 114 115 // Needed if zlib unused or init aborted before deflateInit 116 memset(&(s->zstream), 0, sizeof(z_stream)); 117 118 s->last_key_frame=0; 119 120 s->image_width = avctx->width; 121 s->image_height = avctx->height; 122 123 s->tmpblock = av_mallocz(3*256*256); 124 s->encbuffer = av_mallocz(s->image_width*s->image_height*3); 125 126 if (!s->tmpblock || !s->encbuffer) { 127 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); 128 return -1; 129 } 130 131 return 0; 132} 133 134 135static int encode_bitstream(FlashSVContext *s, AVFrame *p, uint8_t *buf, int buf_size, 136 int block_width, int block_height, uint8_t *previous_frame, int* I_frame) { 137 138 PutBitContext pb; 139 int h_blocks, v_blocks, h_part, v_part, i, j; 140 int buf_pos, res; 141 int pred_blocks = 0; 142 143 init_put_bits(&pb, buf, buf_size*8); 144 145 put_bits(&pb, 4, (block_width/16)-1); 146 put_bits(&pb, 12, s->image_width); 147 put_bits(&pb, 4, (block_height/16)-1); 148 put_bits(&pb, 12, s->image_height); 149 flush_put_bits(&pb); 150 buf_pos=4; 151 152 h_blocks = s->image_width / block_width; 153 h_part = s->image_width % block_width; 154 v_blocks = s->image_height / block_height; 155 v_part = s->image_height % block_height; 156 157 /* loop over all block columns */ 158 for (j = 0; j < v_blocks + (v_part?1:0); j++) 159 { 160 161 int hp = j*block_height; // horiz position in frame 162 int hs = (j<v_blocks)?block_height:v_part; // size of block 163 164 /* loop over all block rows */ 165 for (i = 0; i < h_blocks + (h_part?1:0); i++) 166 { 167 int wp = i*block_width; // vert position in frame 168 int ws = (i<h_blocks)?block_width:h_part; // size of block 169 int ret=Z_OK; 170 uint8_t *ptr; 171 172 ptr = buf+buf_pos; 173 174 //copy the block to the temp buffer before compression (if it differs from the previous frame's block) 175 res = copy_region_enc(p->data[0], s->tmpblock, s->image_height-(hp+hs+1), wp, hs, ws, p->linesize[0], previous_frame); 176 177 if (res || *I_frame) { 178 unsigned long zsize; 179 zsize = 3*block_width*block_height; 180 ret = compress2(ptr+2, &zsize, s->tmpblock, 3*ws*hs, 9); 181 182 183 //ret = deflateReset(&(s->zstream)); 184 if (ret != Z_OK) 185 av_log(s->avctx, AV_LOG_ERROR, "error while compressing block %dx%d\n", i, j); 186 187 bytestream_put_be16(&ptr,(unsigned int)zsize); 188 buf_pos += zsize+2; 189 //av_log(avctx, AV_LOG_ERROR, "buf_pos = %d\n", buf_pos); 190 } else { 191 pred_blocks++; 192 bytestream_put_be16(&ptr,0); 193 buf_pos += 2; 194 } 195 } 196 } 197 198 if (pred_blocks) 199 *I_frame = 0; 200 else 201 *I_frame = 1; 202 203 return buf_pos; 204} 205 206 207static int flashsv_encode_frame(AVCodecContext *avctx, uint8_t *buf, int buf_size, void *data) 208{ 209 FlashSVContext * const s = avctx->priv_data; 210 AVFrame *pict = data; 211 AVFrame * const p = &s->frame; 212 uint8_t *pfptr; 213 int res; 214 int I_frame = 0; 215 int opt_w, opt_h; 216 217 *p = *pict; 218 219 /* First frame needs to be a keyframe */ 220 if (avctx->frame_number == 0) { 221 s->previous_frame = av_mallocz(FFABS(p->linesize[0])*s->image_height); 222 if (!s->previous_frame) { 223 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); 224 return -1; 225 } 226 I_frame = 1; 227 } 228 229 if (p->linesize[0] < 0) 230 pfptr = s->previous_frame - ((s->image_height-1) * p->linesize[0]); 231 else 232 pfptr = s->previous_frame; 233 234 /* Check the placement of keyframes */ 235 if (avctx->gop_size > 0) { 236 if (avctx->frame_number >= s->last_key_frame + avctx->gop_size) { 237 I_frame = 1; 238 } 239 } 240 241 opt_w=4; 242 opt_h=4; 243 244 if (buf_size < s->image_width*s->image_height*3) { 245 //Conservative upper bound check for compressed data 246 av_log(avctx, AV_LOG_ERROR, "buf_size %d < %d\n", buf_size, s->image_width*s->image_height*3); 247 return -1; 248 } 249 250 res = encode_bitstream(s, p, buf, buf_size, opt_w*16, opt_h*16, pfptr, &I_frame); 251 252 //save the current frame 253 if(p->linesize[0] > 0) 254 memcpy(s->previous_frame, p->data[0], s->image_height*p->linesize[0]); 255 else 256 memcpy(s->previous_frame, p->data[0] + p->linesize[0] * (s->image_height-1), s->image_height*FFABS(p->linesize[0])); 257 258 //mark the frame type so the muxer can mux it correctly 259 if (I_frame) { 260 p->pict_type = FF_I_TYPE; 261 p->key_frame = 1; 262 s->last_key_frame = avctx->frame_number; 263 av_log(avctx, AV_LOG_DEBUG, "Inserting key frame at frame %d\n",avctx->frame_number); 264 } else { 265 p->pict_type = FF_P_TYPE; 266 p->key_frame = 0; 267 } 268 269 avctx->coded_frame = p; 270 271 return res; 272} 273 274static av_cold int flashsv_encode_end(AVCodecContext *avctx) 275{ 276 FlashSVContext *s = avctx->priv_data; 277 278 deflateEnd(&(s->zstream)); 279 280 av_free(s->encbuffer); 281 av_free(s->previous_frame); 282 av_free(s->tmpblock); 283 284 return 0; 285} 286 287AVCodec flashsv_encoder = { 288 "flashsv", 289 CODEC_TYPE_VIDEO, 290 CODEC_ID_FLASHSV, 291 sizeof(FlashSVContext), 292 flashsv_encode_init, 293 flashsv_encode_frame, 294 flashsv_encode_end, 295 .pix_fmts = (enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_NONE}, 296 .long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video"), 297}; 298 299