1/* 2 * Interplay C93 video decoder 3 * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com> 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#include "avcodec.h" 23#include "bytestream.h" 24#include "codec_internal.h" 25#include "internal.h" 26 27typedef struct C93DecoderContext { 28 AVFrame *pictures[2]; 29 int currentpic; 30} C93DecoderContext; 31 32typedef enum { 33 C93_8X8_FROM_PREV = 0x02, 34 C93_4X4_FROM_PREV = 0x06, 35 C93_4X4_FROM_CURR = 0x07, 36 C93_8X8_2COLOR = 0x08, 37 C93_4X4_2COLOR = 0x0A, 38 C93_4X4_4COLOR_GRP = 0x0B, 39 C93_4X4_4COLOR = 0x0D, 40 C93_NOOP = 0x0E, 41 C93_8X8_INTRA = 0x0F, 42} C93BlockType; 43 44#define WIDTH 320 45#define HEIGHT 192 46 47#define C93_HAS_PALETTE 0x01 48#define C93_FIRST_FRAME 0x02 49 50static av_cold int decode_end(AVCodecContext *avctx) 51{ 52 C93DecoderContext * const c93 = avctx->priv_data; 53 54 av_frame_free(&c93->pictures[0]); 55 av_frame_free(&c93->pictures[1]); 56 57 return 0; 58} 59 60static av_cold int decode_init(AVCodecContext *avctx) 61{ 62 C93DecoderContext *s = avctx->priv_data; 63 avctx->pix_fmt = AV_PIX_FMT_PAL8; 64 65 s->pictures[0] = av_frame_alloc(); 66 s->pictures[1] = av_frame_alloc(); 67 if (!s->pictures[0] || !s->pictures[1]) 68 return AVERROR(ENOMEM); 69 70 return 0; 71} 72 73static inline int copy_block(AVCodecContext *avctx, uint8_t *to, 74 uint8_t *from, int offset, int height, int stride) 75{ 76 int i; 77 int width = height; 78 int from_x = offset % WIDTH; 79 int from_y = offset / WIDTH; 80 int overflow = from_x + width - WIDTH; 81 82 if (!from) { 83 /* silently ignoring predictive blocks in first frame */ 84 return 0; 85 } 86 87 if (from_y + height > HEIGHT) { 88 av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n", 89 offset); 90 return AVERROR_INVALIDDATA; 91 } 92 93 if (overflow > 0) { 94 width -= overflow; 95 for (i = 0; i < height; i++) { 96 memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow); 97 } 98 } 99 100 for (i = 0; i < height; i++) { 101 memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width); 102 } 103 104 return 0; 105} 106 107static inline void draw_n_color(uint8_t *out, int stride, int width, 108 int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col) 109{ 110 int x, y; 111 for (y = 0; y < height; y++) { 112 if (grps) 113 cols[0] = grps[3 * (y >> 1)]; 114 for (x = 0; x < width; x++) { 115 if (grps) 116 cols[1]= grps[(x >> 1) + 1]; 117 out[x + y*stride] = cols[col & ((1 << bpp) - 1)]; 118 col >>= bpp; 119 } 120 } 121} 122 123static int decode_frame(AVCodecContext *avctx, AVFrame *rframe, 124 int *got_frame, AVPacket *avpkt) 125{ 126 const uint8_t *buf = avpkt->data; 127 int buf_size = avpkt->size; 128 C93DecoderContext * const c93 = avctx->priv_data; 129 AVFrame * const newpic = c93->pictures[c93->currentpic]; 130 AVFrame * const oldpic = c93->pictures[c93->currentpic^1]; 131 GetByteContext gb; 132 uint8_t *out; 133 int stride, ret, i, x, y, b, bt = 0; 134 135 if ((ret = ff_set_dimensions(avctx, WIDTH, HEIGHT)) < 0) 136 return ret; 137 138 c93->currentpic ^= 1; 139 140 if ((ret = ff_reget_buffer(avctx, newpic, 0)) < 0) 141 return ret; 142 143 stride = newpic->linesize[0]; 144 145 bytestream2_init(&gb, buf, buf_size); 146 b = bytestream2_get_byte(&gb); 147 if (b & C93_FIRST_FRAME) { 148 newpic->pict_type = AV_PICTURE_TYPE_I; 149 newpic->key_frame = 1; 150 } else { 151 newpic->pict_type = AV_PICTURE_TYPE_P; 152 newpic->key_frame = 0; 153 } 154 155 for (y = 0; y < HEIGHT; y += 8) { 156 out = newpic->data[0] + y * stride; 157 for (x = 0; x < WIDTH; x += 8) { 158 uint8_t *copy_from = oldpic->data[0]; 159 unsigned int offset, j; 160 uint8_t cols[4], grps[4]; 161 C93BlockType block_type; 162 163 if (!bt) 164 bt = bytestream2_get_byte(&gb); 165 166 block_type= bt & 0x0F; 167 switch (block_type) { 168 case C93_8X8_FROM_PREV: 169 offset = bytestream2_get_le16(&gb); 170 if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0) 171 return ret; 172 break; 173 174 case C93_4X4_FROM_CURR: 175 copy_from = newpic->data[0]; 176 case C93_4X4_FROM_PREV: 177 for (j = 0; j < 8; j += 4) { 178 for (i = 0; i < 8; i += 4) { 179 int offset = bytestream2_get_le16(&gb); 180 int from_x = offset % WIDTH; 181 int from_y = offset / WIDTH; 182 if (block_type == C93_4X4_FROM_CURR && from_y == y+j && 183 (FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) { 184 avpriv_request_sample(avctx, "block overlap %d %d %d %d", from_x, x+i, from_y, y+j); 185 return AVERROR_INVALIDDATA; 186 } 187 if ((ret = copy_block(avctx, &out[j*stride+i], 188 copy_from, offset, 4, stride)) < 0) 189 return ret; 190 } 191 } 192 break; 193 194 case C93_8X8_2COLOR: 195 bytestream2_get_buffer(&gb, cols, 2); 196 for (i = 0; i < 8; i++) { 197 draw_n_color(out + i*stride, stride, 8, 1, 1, cols, 198 NULL, bytestream2_get_byte(&gb)); 199 } 200 201 break; 202 203 case C93_4X4_2COLOR: 204 case C93_4X4_4COLOR: 205 case C93_4X4_4COLOR_GRP: 206 for (j = 0; j < 8; j += 4) { 207 for (i = 0; i < 8; i += 4) { 208 if (block_type == C93_4X4_2COLOR) { 209 bytestream2_get_buffer(&gb, cols, 2); 210 draw_n_color(out + i + j*stride, stride, 4, 4, 211 1, cols, NULL, bytestream2_get_le16(&gb)); 212 } else if (block_type == C93_4X4_4COLOR) { 213 bytestream2_get_buffer(&gb, cols, 4); 214 draw_n_color(out + i + j*stride, stride, 4, 4, 215 2, cols, NULL, bytestream2_get_le32(&gb)); 216 } else { 217 bytestream2_get_buffer(&gb, grps, 4); 218 draw_n_color(out + i + j*stride, stride, 4, 4, 219 1, cols, grps, bytestream2_get_le16(&gb)); 220 } 221 } 222 } 223 break; 224 225 case C93_NOOP: 226 break; 227 228 case C93_8X8_INTRA: 229 for (j = 0; j < 8; j++) 230 bytestream2_get_buffer(&gb, out + j*stride, 8); 231 break; 232 233 default: 234 av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n", 235 block_type, x, y); 236 return AVERROR_INVALIDDATA; 237 } 238 bt >>= 4; 239 out += 8; 240 } 241 } 242 243 if (b & C93_HAS_PALETTE) { 244 uint32_t *palette = (uint32_t *) newpic->data[1]; 245 for (i = 0; i < 256; i++) { 246 palette[i] = 0xFFU << 24 | bytestream2_get_be24(&gb); 247 } 248 newpic->palette_has_changed = 1; 249 } else { 250 if (oldpic->data[1]) 251 memcpy(newpic->data[1], oldpic->data[1], 256 * 4); 252 } 253 254 if ((ret = av_frame_ref(rframe, newpic)) < 0) 255 return ret; 256 *got_frame = 1; 257 258 return buf_size; 259} 260 261const FFCodec ff_c93_decoder = { 262 .p.name = "c93", 263 .p.long_name = NULL_IF_CONFIG_SMALL("Interplay C93"), 264 .p.type = AVMEDIA_TYPE_VIDEO, 265 .p.id = AV_CODEC_ID_C93, 266 .priv_data_size = sizeof(C93DecoderContext), 267 .init = decode_init, 268 .close = decode_end, 269 FF_CODEC_DECODE_CB(decode_frame), 270 .p.capabilities = AV_CODEC_CAP_DR1, 271 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP, 272}; 273