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 Libav. 7 * 8 * Libav 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 * Libav 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 Libav; 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 27 * Flash Screen Video encoder 28 * @author Alex Beregszaszi 29 * @author Benjamin Larsson 30 * 31 * A description of the bitstream format for Flash Screen Video version 1/2 32 * is part of the SWF File Format Specification (version 10), which can be 33 * downloaded from http://www.adobe.com/devnet/swf.html. 34 */ 35 36/* 37 * Encoding ideas: A basic encoder would just use a fixed block size. 38 * Block sizes can be multiples of 16, from 16 to 256. The blocks don't 39 * have to be quadratic. A brute force search with a set of different 40 * block sizes should give a better result than to just use a fixed size. 41 * 42 * TODO: 43 * Don't reencode the frame in brute force mode if the frame is a dupe. 44 * Speed up. Make the difference check faster. 45 */ 46 47#include <stdio.h> 48#include <stdlib.h> 49#include <zlib.h> 50 51#include "avcodec.h" 52#include "put_bits.h" 53#include "bytestream.h" 54 55 56typedef struct FlashSVContext { 57 AVCodecContext *avctx; 58 uint8_t *previous_frame; 59 AVFrame frame; 60 int image_width, image_height; 61 int block_width, block_height; 62 uint8_t *tmpblock; 63 uint8_t *encbuffer; 64 int block_size; 65 z_stream zstream; 66 int last_key_frame; 67} FlashSVContext; 68 69static int copy_region_enc(uint8_t *sptr, uint8_t *dptr, int dx, int dy, 70 int h, int w, int stride, uint8_t *pfptr) 71{ 72 int i, j; 73 uint8_t *nsptr; 74 uint8_t *npfptr; 75 int diff = 0; 76 77 for (i = dx + h; i > dx; i--) { 78 nsptr = sptr + i * stride + dy * 3; 79 npfptr = pfptr + i * stride + dy * 3; 80 for (j = 0; j < w * 3; j++) { 81 diff |= npfptr[j] ^ nsptr[j]; 82 dptr[j] = nsptr[j]; 83 } 84 dptr += w * 3; 85 } 86 if (diff) 87 return 1; 88 return 0; 89} 90 91static av_cold int flashsv_encode_init(AVCodecContext *avctx) 92{ 93 FlashSVContext *s = avctx->priv_data; 94 95 s->avctx = avctx; 96 97 if (avctx->width > 4095 || avctx->height > 4095) { 98 av_log(avctx, AV_LOG_ERROR, 99 "Input dimensions too large, input must be max 4096x4096 !\n"); 100 return AVERROR_INVALIDDATA; 101 } 102 103 // Needed if zlib unused or init aborted before deflateInit 104 memset(&s->zstream, 0, sizeof(z_stream)); 105 106 s->last_key_frame = 0; 107 108 s->image_width = avctx->width; 109 s->image_height = avctx->height; 110 111 s->tmpblock = av_mallocz(3 * 256 * 256); 112 s->encbuffer = av_mallocz(s->image_width * s->image_height * 3); 113 114 if (!s->tmpblock || !s->encbuffer) { 115 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); 116 return AVERROR(ENOMEM); 117 } 118 119 return 0; 120} 121 122 123static int encode_bitstream(FlashSVContext *s, AVFrame *p, uint8_t *buf, 124 int buf_size, int block_width, int block_height, 125 uint8_t *previous_frame, int *I_frame) 126{ 127 128 PutBitContext pb; 129 int h_blocks, v_blocks, h_part, v_part, i, j; 130 int buf_pos, res; 131 int pred_blocks = 0; 132 133 init_put_bits(&pb, buf, buf_size * 8); 134 135 put_bits(&pb, 4, block_width / 16 - 1); 136 put_bits(&pb, 12, s->image_width); 137 put_bits(&pb, 4, block_height / 16 - 1); 138 put_bits(&pb, 12, s->image_height); 139 flush_put_bits(&pb); 140 buf_pos = 4; 141 142 h_blocks = s->image_width / block_width; 143 h_part = s->image_width % block_width; 144 v_blocks = s->image_height / block_height; 145 v_part = s->image_height % block_height; 146 147 /* loop over all block columns */ 148 for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) { 149 150 int y_pos = j * block_height; // vertical position in frame 151 int cur_blk_height = (j < v_blocks) ? block_height : v_part; 152 153 /* loop over all block rows */ 154 for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) { 155 int x_pos = i * block_width; // horizontal position in frame 156 int cur_blk_width = (i < h_blocks) ? block_width : h_part; 157 int ret = Z_OK; 158 uint8_t *ptr = buf + buf_pos; 159 160 /* copy the block to the temp buffer before compression 161 * (if it differs from the previous frame's block) */ 162 res = copy_region_enc(p->data[0], s->tmpblock, 163 s->image_height - (y_pos + cur_blk_height + 1), 164 x_pos, cur_blk_height, cur_blk_width, 165 p->linesize[0], previous_frame); 166 167 if (res || *I_frame) { 168 unsigned long zsize = 3 * block_width * block_height; 169 ret = compress2(ptr + 2, &zsize, s->tmpblock, 170 3 * cur_blk_width * cur_blk_height, 9); 171 172 //ret = deflateReset(&s->zstream); 173 if (ret != Z_OK) 174 av_log(s->avctx, AV_LOG_ERROR, 175 "error while compressing block %dx%d\n", i, j); 176 177 bytestream_put_be16(&ptr, zsize); 178 buf_pos += zsize + 2; 179 av_dlog(s->avctx, "buf_pos = %d\n", buf_pos); 180 } else { 181 pred_blocks++; 182 bytestream_put_be16(&ptr, 0); 183 buf_pos += 2; 184 } 185 } 186 } 187 188 if (pred_blocks) 189 *I_frame = 0; 190 else 191 *I_frame = 1; 192 193 return buf_pos; 194} 195 196 197static int flashsv_encode_frame(AVCodecContext *avctx, uint8_t *buf, 198 int buf_size, void *data) 199{ 200 FlashSVContext * const s = avctx->priv_data; 201 AVFrame *pict = data; 202 AVFrame * const p = &s->frame; 203 uint8_t *pfptr; 204 int res; 205 int I_frame = 0; 206 int opt_w = 4, opt_h = 4; 207 208 *p = *pict; 209 210 /* First frame needs to be a keyframe */ 211 if (avctx->frame_number == 0) { 212 s->previous_frame = av_mallocz(FFABS(p->linesize[0]) * s->image_height); 213 if (!s->previous_frame) { 214 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); 215 return AVERROR(ENOMEM); 216 } 217 I_frame = 1; 218 } 219 220 if (p->linesize[0] < 0) 221 pfptr = s->previous_frame - (s->image_height - 1) * p->linesize[0]; 222 else 223 pfptr = s->previous_frame; 224 225 /* Check the placement of keyframes */ 226 if (avctx->gop_size > 0 && 227 avctx->frame_number >= s->last_key_frame + avctx->gop_size) { 228 I_frame = 1; 229 } 230 231 if (buf_size < s->image_width * s->image_height * 3) { 232 //Conservative upper bound check for compressed data 233 av_log(avctx, AV_LOG_ERROR, "buf_size %d < %d\n", 234 buf_size, s->image_width * s->image_height * 3); 235 return -1; 236 } 237 238 res = encode_bitstream(s, p, buf, buf_size, opt_w * 16, opt_h * 16, 239 pfptr, &I_frame); 240 241 //save the current frame 242 if (p->linesize[0] > 0) 243 memcpy(s->previous_frame, p->data[0], s->image_height * p->linesize[0]); 244 else 245 memcpy(s->previous_frame, 246 p->data[0] + p->linesize[0] * (s->image_height - 1), 247 s->image_height * FFABS(p->linesize[0])); 248 249 //mark the frame type so the muxer can mux it correctly 250 if (I_frame) { 251 p->pict_type = AV_PICTURE_TYPE_I; 252 p->key_frame = 1; 253 s->last_key_frame = avctx->frame_number; 254 av_dlog(avctx, "Inserting keyframe at frame %d\n", avctx->frame_number); 255 } else { 256 p->pict_type = AV_PICTURE_TYPE_P; 257 p->key_frame = 0; 258 } 259 260 avctx->coded_frame = p; 261 262 return res; 263} 264 265static av_cold int flashsv_encode_end(AVCodecContext *avctx) 266{ 267 FlashSVContext *s = avctx->priv_data; 268 269 deflateEnd(&s->zstream); 270 271 av_free(s->encbuffer); 272 av_free(s->previous_frame); 273 av_free(s->tmpblock); 274 275 return 0; 276} 277 278AVCodec ff_flashsv_encoder = { 279 .name = "flashsv", 280 .type = AVMEDIA_TYPE_VIDEO, 281 .id = CODEC_ID_FLASHSV, 282 .priv_data_size = sizeof(FlashSVContext), 283 .init = flashsv_encode_init, 284 .encode = flashsv_encode_frame, 285 .close = flashsv_encode_end, 286 .pix_fmts = (const enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_NONE}, 287 .long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video"), 288}; 289 290