libavcodec/c93.c

   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 "decode.h"
  26
  27 typedef struct C93DecoderContext {
  28     AVFrame *pictures[2];
  29     int currentpic;
  30 } C93DecoderContext;
  31
  32 typedef 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
  50 static 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
  60 static 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
  73 static 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
 107 static 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
 123 static 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 ret, i, x, y, b, bt = 0;
 134     ptrdiff_t stride;
 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)) < 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->flags |= AV_FRAME_FLAG_KEY;
 151     } else {
 152         newpic->pict_type = AV_PICTURE_TYPE_P;
 153         newpic->flags &= ~AV_FRAME_FLAG_KEY;
 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             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                 int 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
 175             case C93_4X4_FROM_CURR:
 176                 copy_from = newpic->data[0];
 177             case C93_4X4_FROM_PREV:
 178                 for (int 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", 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 (int 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 (int 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 #if FF_API_PALETTE_HAS_CHANGED
 250 FF_DISABLE_DEPRECATION_WARNINGS
 251         newpic->palette_has_changed = 1;
 252 FF_ENABLE_DEPRECATION_WARNINGS
 253 #endif
 254     } else {
 255         if (oldpic->data[1])
 256             memcpy(newpic->data[1], oldpic->data[1], 256 * 4);
 257     }
 258
 259     if ((ret = av_frame_ref(rframe, newpic)) < 0)
 260         return ret;
 261     *got_frame = 1;
 262
 263     return buf_size;
 264 }
 265
 266 const FFCodec ff_c93_decoder = {
 267     .p.name         = "c93",
 268     CODEC_LONG_NAME("Interplay C93"),
 269     .p.type         = AVMEDIA_TYPE_VIDEO,
 270     .p.id           = AV_CODEC_ID_C93,
 271     .priv_data_size = sizeof(C93DecoderContext),
 272     .init           = decode_init,
 273     .close          = decode_end,
 274     FF_CODEC_DECODE_CB(decode_frame),
 275     .p.capabilities = AV_CODEC_CAP_DR1,
 276     .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
 277 };