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 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 "internal.h" 53#include "put_bits.h" 54#include "bytestream.h" 55 56 57typedef struct FlashSVContext { 58 AVCodecContext *avctx; 59 uint8_t *previous_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_end(AVCodecContext *avctx) 92{ 93 FlashSVContext *s = avctx->priv_data; 94 95 deflateEnd(&s->zstream); 96 97 av_free(s->encbuffer); 98 av_free(s->previous_frame); 99 av_free(s->tmpblock); 100 101 av_frame_free(&avctx->coded_frame); 102 103 return 0; 104} 105 106static av_cold int flashsv_encode_init(AVCodecContext *avctx) 107{ 108 FlashSVContext *s = avctx->priv_data; 109 110 s->avctx = avctx; 111 112 if (avctx->width > 4095 || avctx->height > 4095) { 113 av_log(avctx, AV_LOG_ERROR, 114 "Input dimensions too large, input must be max 4096x4096 !\n"); 115 return AVERROR_INVALIDDATA; 116 } 117 118 // Needed if zlib unused or init aborted before deflateInit 119 memset(&s->zstream, 0, sizeof(z_stream)); 120 121 s->last_key_frame = 0; 122 123 s->image_width = avctx->width; 124 s->image_height = avctx->height; 125 126 s->tmpblock = av_mallocz(3 * 256 * 256); 127 s->encbuffer = av_mallocz(s->image_width * s->image_height * 3); 128 129 if (!s->tmpblock || !s->encbuffer) { 130 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); 131 return AVERROR(ENOMEM); 132 } 133 134 avctx->coded_frame = av_frame_alloc(); 135 if (!avctx->coded_frame) { 136 flashsv_encode_end(avctx); 137 return AVERROR(ENOMEM); 138 } 139 140 return 0; 141} 142 143 144static int encode_bitstream(FlashSVContext *s, const AVFrame *p, uint8_t *buf, 145 int buf_size, int block_width, int block_height, 146 uint8_t *previous_frame, int *I_frame) 147{ 148 149 PutBitContext pb; 150 int h_blocks, v_blocks, h_part, v_part, i, j; 151 int buf_pos, res; 152 int pred_blocks = 0; 153 154 init_put_bits(&pb, buf, buf_size * 8); 155 156 put_bits(&pb, 4, block_width / 16 - 1); 157 put_bits(&pb, 12, s->image_width); 158 put_bits(&pb, 4, block_height / 16 - 1); 159 put_bits(&pb, 12, s->image_height); 160 flush_put_bits(&pb); 161 buf_pos = 4; 162 163 h_blocks = s->image_width / block_width; 164 h_part = s->image_width % block_width; 165 v_blocks = s->image_height / block_height; 166 v_part = s->image_height % block_height; 167 168 /* loop over all block columns */ 169 for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) { 170 171 int y_pos = j * block_height; // vertical position in frame 172 int cur_blk_height = (j < v_blocks) ? block_height : v_part; 173 174 /* loop over all block rows */ 175 for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) { 176 int x_pos = i * block_width; // horizontal position in frame 177 int cur_blk_width = (i < h_blocks) ? block_width : h_part; 178 int ret = Z_OK; 179 uint8_t *ptr = buf + buf_pos; 180 181 /* copy the block to the temp buffer before compression 182 * (if it differs from the previous frame's block) */ 183 res = copy_region_enc(p->data[0], s->tmpblock, 184 s->image_height - (y_pos + cur_blk_height + 1), 185 x_pos, cur_blk_height, cur_blk_width, 186 p->linesize[0], previous_frame); 187 188 if (res || *I_frame) { 189 unsigned long zsize = 3 * block_width * block_height; 190 ret = compress2(ptr + 2, &zsize, s->tmpblock, 191 3 * cur_blk_width * cur_blk_height, 9); 192 193 //ret = deflateReset(&s->zstream); 194 if (ret != Z_OK) 195 av_log(s->avctx, AV_LOG_ERROR, 196 "error while compressing block %dx%d\n", i, j); 197 198 bytestream_put_be16(&ptr, zsize); 199 buf_pos += zsize + 2; 200 av_dlog(s->avctx, "buf_pos = %d\n", buf_pos); 201 } else { 202 pred_blocks++; 203 bytestream_put_be16(&ptr, 0); 204 buf_pos += 2; 205 } 206 } 207 } 208 209 if (pred_blocks) 210 *I_frame = 0; 211 else 212 *I_frame = 1; 213 214 return buf_pos; 215} 216 217 218static int flashsv_encode_frame(AVCodecContext *avctx, AVPacket *pkt, 219 const AVFrame *pict, int *got_packet) 220{ 221 FlashSVContext * const s = avctx->priv_data; 222 const AVFrame * const p = pict; 223 uint8_t *pfptr; 224 int res; 225 int I_frame = 0; 226 int opt_w = 4, opt_h = 4; 227 228 /* First frame needs to be a keyframe */ 229 if (avctx->frame_number == 0) { 230 s->previous_frame = av_mallocz(FFABS(p->linesize[0]) * s->image_height); 231 if (!s->previous_frame) { 232 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); 233 return AVERROR(ENOMEM); 234 } 235 I_frame = 1; 236 } 237 238 if (p->linesize[0] < 0) 239 pfptr = s->previous_frame - (s->image_height - 1) * p->linesize[0]; 240 else 241 pfptr = s->previous_frame; 242 243 /* Check the placement of keyframes */ 244 if (avctx->gop_size > 0 && 245 avctx->frame_number >= s->last_key_frame + avctx->gop_size) { 246 I_frame = 1; 247 } 248 249 if ((res = ff_alloc_packet2(avctx, pkt, s->image_width * s->image_height * 3)) < 0) 250 return res; 251 252 pkt->size = encode_bitstream(s, p, pkt->data, pkt->size, opt_w * 16, opt_h * 16, 253 pfptr, &I_frame); 254 255 //save the current frame 256 if (p->linesize[0] > 0) 257 memcpy(s->previous_frame, p->data[0], s->image_height * p->linesize[0]); 258 else 259 memcpy(s->previous_frame, 260 p->data[0] + p->linesize[0] * (s->image_height - 1), 261 s->image_height * FFABS(p->linesize[0])); 262 263 //mark the frame type so the muxer can mux it correctly 264 if (I_frame) { 265 avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I; 266 avctx->coded_frame->key_frame = 1; 267 s->last_key_frame = avctx->frame_number; 268 av_dlog(avctx, "Inserting keyframe at frame %d\n", avctx->frame_number); 269 } else { 270 avctx->coded_frame->pict_type = AV_PICTURE_TYPE_P; 271 avctx->coded_frame->key_frame = 0; 272 } 273 274 if (avctx->coded_frame->key_frame) 275 pkt->flags |= AV_PKT_FLAG_KEY; 276 *got_packet = 1; 277 278 return 0; 279} 280 281AVCodec ff_flashsv_encoder = { 282 .name = "flashsv", 283 .long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video"), 284 .type = AVMEDIA_TYPE_VIDEO, 285 .id = AV_CODEC_ID_FLASHSV, 286 .priv_data_size = sizeof(FlashSVContext), 287 .init = flashsv_encode_init, 288 .encode2 = flashsv_encode_frame, 289 .close = flashsv_encode_end, 290 .pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_BGR24, AV_PIX_FMT_NONE }, 291}; 292