| 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 "internal.h" |
| 25 | |
| 26 | typedef struct { |
| 27 | AVFrame *pictures[2]; |
| 28 | int currentpic; |
| 29 | } C93DecoderContext; |
| 30 | |
| 31 | typedef enum { |
| 32 | C93_8X8_FROM_PREV = 0x02, |
| 33 | C93_4X4_FROM_PREV = 0x06, |
| 34 | C93_4X4_FROM_CURR = 0x07, |
| 35 | C93_8X8_2COLOR = 0x08, |
| 36 | C93_4X4_2COLOR = 0x0A, |
| 37 | C93_4X4_4COLOR_GRP = 0x0B, |
| 38 | C93_4X4_4COLOR = 0x0D, |
| 39 | C93_NOOP = 0x0E, |
| 40 | C93_8X8_INTRA = 0x0F, |
| 41 | } C93BlockType; |
| 42 | |
| 43 | #define WIDTH 320 |
| 44 | #define HEIGHT 192 |
| 45 | |
| 46 | #define C93_HAS_PALETTE 0x01 |
| 47 | #define C93_FIRST_FRAME 0x02 |
| 48 | |
| 49 | static av_cold int decode_end(AVCodecContext *avctx) |
| 50 | { |
| 51 | C93DecoderContext * const c93 = avctx->priv_data; |
| 52 | |
| 53 | av_frame_free(&c93->pictures[0]); |
| 54 | av_frame_free(&c93->pictures[1]); |
| 55 | |
| 56 | return 0; |
| 57 | } |
| 58 | |
| 59 | static av_cold int decode_init(AVCodecContext *avctx) |
| 60 | { |
| 61 | C93DecoderContext *s = avctx->priv_data; |
| 62 | avctx->pix_fmt = AV_PIX_FMT_PAL8; |
| 63 | |
| 64 | s->pictures[0] = av_frame_alloc(); |
| 65 | s->pictures[1] = av_frame_alloc(); |
| 66 | if (!s->pictures[0] || !s->pictures[1]) { |
| 67 | decode_end(avctx); |
| 68 | return AVERROR(ENOMEM); |
| 69 | } |
| 70 | |
| 71 | return 0; |
| 72 | } |
| 73 | |
| 74 | static inline int copy_block(AVCodecContext *avctx, uint8_t *to, |
| 75 | uint8_t *from, int offset, int height, int stride) |
| 76 | { |
| 77 | int i; |
| 78 | int width = height; |
| 79 | int from_x = offset % WIDTH; |
| 80 | int from_y = offset / WIDTH; |
| 81 | int overflow = from_x + width - WIDTH; |
| 82 | |
| 83 | if (!from) { |
| 84 | /* silently ignoring predictive blocks in first frame */ |
| 85 | return 0; |
| 86 | } |
| 87 | |
| 88 | if (from_y + height > HEIGHT) { |
| 89 | av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n", |
| 90 | offset); |
| 91 | return AVERROR_INVALIDDATA; |
| 92 | } |
| 93 | |
| 94 | if (overflow > 0) { |
| 95 | width -= overflow; |
| 96 | for (i = 0; i < height; i++) { |
| 97 | memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow); |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | for (i = 0; i < height; i++) { |
| 102 | memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width); |
| 103 | } |
| 104 | |
| 105 | return 0; |
| 106 | } |
| 107 | |
| 108 | static inline void draw_n_color(uint8_t *out, int stride, int width, |
| 109 | int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col) |
| 110 | { |
| 111 | int x, y; |
| 112 | for (y = 0; y < height; y++) { |
| 113 | if (grps) |
| 114 | cols[0] = grps[3 * (y >> 1)]; |
| 115 | for (x = 0; x < width; x++) { |
| 116 | if (grps) |
| 117 | cols[1]= grps[(x >> 1) + 1]; |
| 118 | out[x + y*stride] = cols[col & ((1 << bpp) - 1)]; |
| 119 | col >>= bpp; |
| 120 | } |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | static int decode_frame(AVCodecContext *avctx, void *data, |
| 125 | int *got_frame, AVPacket *avpkt) |
| 126 | { |
| 127 | const uint8_t *buf = avpkt->data; |
| 128 | int buf_size = avpkt->size; |
| 129 | C93DecoderContext * const c93 = avctx->priv_data; |
| 130 | AVFrame * const newpic = c93->pictures[c93->currentpic]; |
| 131 | AVFrame * const oldpic = c93->pictures[c93->currentpic^1]; |
| 132 | GetByteContext gb; |
| 133 | uint8_t *out; |
| 134 | int stride, ret, i, x, y, b, bt = 0; |
| 135 | |
| 136 | if ((ret = ff_set_dimensions(avctx, WIDTH, HEIGHT)) < 0) |
| 137 | return ret; |
| 138 | |
| 139 | c93->currentpic ^= 1; |
| 140 | |
| 141 | if ((ret = ff_reget_buffer(avctx, newpic)) < 0) |
| 142 | return ret; |
| 143 | |
| 144 | stride = newpic->linesize[0]; |
| 145 | |
| 146 | bytestream2_init(&gb, buf, buf_size); |
| 147 | b = bytestream2_get_byte(&gb); |
| 148 | if (b & C93_FIRST_FRAME) { |
| 149 | newpic->pict_type = AV_PICTURE_TYPE_I; |
| 150 | newpic->key_frame = 1; |
| 151 | } else { |
| 152 | newpic->pict_type = AV_PICTURE_TYPE_P; |
| 153 | newpic->key_frame = 0; |
| 154 | } |
| 155 | |
| 156 | for (y = 0; y < HEIGHT; y += 8) { |
| 157 | out = newpic->data[0] + y * stride; |
| 158 | for (x = 0; x < WIDTH; x += 8) { |
| 159 | uint8_t *copy_from = oldpic->data[0]; |
| 160 | unsigned int offset, j; |
| 161 | uint8_t cols[4], grps[4]; |
| 162 | C93BlockType block_type; |
| 163 | |
| 164 | if (!bt) |
| 165 | bt = bytestream2_get_byte(&gb); |
| 166 | |
| 167 | block_type= bt & 0x0F; |
| 168 | switch (block_type) { |
| 169 | case C93_8X8_FROM_PREV: |
| 170 | offset = bytestream2_get_le16(&gb); |
| 171 | if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0) |
| 172 | return ret; |
| 173 | break; |
| 174 | |
| 175 | case C93_4X4_FROM_CURR: |
| 176 | copy_from = newpic->data[0]; |
| 177 | case C93_4X4_FROM_PREV: |
| 178 | for (j = 0; j < 8; j += 4) { |
| 179 | for (i = 0; i < 8; i += 4) { |
| 180 | int offset = bytestream2_get_le16(&gb); |
| 181 | int from_x = offset % WIDTH; |
| 182 | int from_y = offset / WIDTH; |
| 183 | if (block_type == C93_4X4_FROM_CURR && from_y == y+j && |
| 184 | (FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) { |
| 185 | avpriv_request_sample(avctx, "block overlap %d %d %d %d\n", from_x, x+i, from_y, y+j); |
| 186 | return AVERROR_INVALIDDATA; |
| 187 | } |
| 188 | if ((ret = copy_block(avctx, &out[j*stride+i], |
| 189 | copy_from, offset, 4, stride)) < 0) |
| 190 | return ret; |
| 191 | } |
| 192 | } |
| 193 | break; |
| 194 | |
| 195 | case C93_8X8_2COLOR: |
| 196 | bytestream2_get_buffer(&gb, cols, 2); |
| 197 | for (i = 0; i < 8; i++) { |
| 198 | draw_n_color(out + i*stride, stride, 8, 1, 1, cols, |
| 199 | NULL, bytestream2_get_byte(&gb)); |
| 200 | } |
| 201 | |
| 202 | break; |
| 203 | |
| 204 | case C93_4X4_2COLOR: |
| 205 | case C93_4X4_4COLOR: |
| 206 | case C93_4X4_4COLOR_GRP: |
| 207 | for (j = 0; j < 8; j += 4) { |
| 208 | for (i = 0; i < 8; i += 4) { |
| 209 | if (block_type == C93_4X4_2COLOR) { |
| 210 | bytestream2_get_buffer(&gb, cols, 2); |
| 211 | draw_n_color(out + i + j*stride, stride, 4, 4, |
| 212 | 1, cols, NULL, bytestream2_get_le16(&gb)); |
| 213 | } else if (block_type == C93_4X4_4COLOR) { |
| 214 | bytestream2_get_buffer(&gb, cols, 4); |
| 215 | draw_n_color(out + i + j*stride, stride, 4, 4, |
| 216 | 2, cols, NULL, bytestream2_get_le32(&gb)); |
| 217 | } else { |
| 218 | bytestream2_get_buffer(&gb, grps, 4); |
| 219 | draw_n_color(out + i + j*stride, stride, 4, 4, |
| 220 | 1, cols, grps, bytestream2_get_le16(&gb)); |
| 221 | } |
| 222 | } |
| 223 | } |
| 224 | break; |
| 225 | |
| 226 | case C93_NOOP: |
| 227 | break; |
| 228 | |
| 229 | case C93_8X8_INTRA: |
| 230 | for (j = 0; j < 8; j++) |
| 231 | bytestream2_get_buffer(&gb, out + j*stride, 8); |
| 232 | break; |
| 233 | |
| 234 | default: |
| 235 | av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n", |
| 236 | block_type, x, y); |
| 237 | return AVERROR_INVALIDDATA; |
| 238 | } |
| 239 | bt >>= 4; |
| 240 | out += 8; |
| 241 | } |
| 242 | } |
| 243 | |
| 244 | if (b & C93_HAS_PALETTE) { |
| 245 | uint32_t *palette = (uint32_t *) newpic->data[1]; |
| 246 | for (i = 0; i < 256; i++) { |
| 247 | palette[i] = 0xFFU << 24 | bytestream2_get_be24(&gb); |
| 248 | } |
| 249 | newpic->palette_has_changed = 1; |
| 250 | } else { |
| 251 | if (oldpic->data[1]) |
| 252 | memcpy(newpic->data[1], oldpic->data[1], 256 * 4); |
| 253 | } |
| 254 | |
| 255 | if ((ret = av_frame_ref(data, newpic)) < 0) |
| 256 | return ret; |
| 257 | *got_frame = 1; |
| 258 | |
| 259 | return buf_size; |
| 260 | } |
| 261 | |
| 262 | AVCodec ff_c93_decoder = { |
| 263 | .name = "c93", |
| 264 | .long_name = NULL_IF_CONFIG_SMALL("Interplay C93"), |
| 265 | .type = AVMEDIA_TYPE_VIDEO, |
| 266 | .id = AV_CODEC_ID_C93, |
| 267 | .priv_data_size = sizeof(C93DecoderContext), |
| 268 | .init = decode_init, |
| 269 | .close = decode_end, |
| 270 | .decode = decode_frame, |
| 271 | .capabilities = CODEC_CAP_DR1, |
| 272 | }; |