libavcodec/avs.c

   1 /*
   2  * AVS video decoder.
   3  * Copyright (c) 2006  Aurelien Jacobs <aurel@gnuage.org>
   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 "bitstream.h"
  24
  25
  26 typedef struct {
  27     AVFrame picture;
  28 } avs_context_t;
  29
  30 typedef enum {
  31     AVS_VIDEO     = 0x01,
  32     AVS_AUDIO     = 0x02,
  33     AVS_PALETTE   = 0x03,
  34     AVS_GAME_DATA = 0x04,
  35 } avs_block_type_t;
  36
  37 typedef enum {
  38     AVS_I_FRAME     = 0x00,
  39     AVS_P_FRAME_3X3 = 0x01,
  40     AVS_P_FRAME_2X2 = 0x02,
  41     AVS_P_FRAME_2X3 = 0x03,
  42 } avs_video_sub_type_t;
  43
  44
  45 static int
  46 avs_decode_frame(AVCodecContext * avctx,
  47                  void *data, int *data_size, uint8_t * buf, int buf_size)
  48 {
  49     avs_context_t *const avs = avctx->priv_data;
  50     AVFrame *picture = data;
  51     AVFrame *const p = (AVFrame *) & avs->picture;
  52     uint8_t *table, *vect, *out;
  53     int i, j, x, y, stride, vect_w = 3, vect_h = 3;
  54     int sub_type;
  55     avs_block_type_t type;
  56     GetBitContext change_map;
  57
  58     if (avctx->reget_buffer(avctx, p)) {
  59         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  60         return -1;
  61     }
  62     p->reference = 1;
  63     p->pict_type = FF_P_TYPE;
  64     p->key_frame = 0;
  65
  66     out = avs->picture.data[0];
  67     stride = avs->picture.linesize[0];
  68
  69     sub_type = buf[0];
  70     type = buf[1];
  71     buf += 4;
  72
  73     if (type == AVS_PALETTE) {
  74         int first, last;
  75         uint32_t *pal = (uint32_t *) avs->picture.data[1];
  76
  77         first = AV_RL16(buf);
  78         last = first + AV_RL16(buf + 2);
  79         buf += 4;
  80         for (i=first; i<last; i++, buf+=3)
  81             pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2);
  82
  83         sub_type = buf[0];
  84         type = buf[1];
  85         buf += 4;
  86     }
  87
  88     if (type != AVS_VIDEO)
  89         return -1;
  90
  91     switch (sub_type) {
  92     case AVS_I_FRAME:
  93         p->pict_type = FF_I_TYPE;
  94         p->key_frame = 1;
  95     case AVS_P_FRAME_3X3:
  96         vect_w = 3;
  97         vect_h = 3;
  98         break;
  99
 100     case AVS_P_FRAME_2X2:
 101         vect_w = 2;
 102         vect_h = 2;
 103         break;
 104
 105     case AVS_P_FRAME_2X3:
 106         vect_w = 2;
 107         vect_h = 3;
 108         break;
 109
 110     default:
 111       return -1;
 112     }
 113
 114     table = buf + (256 * vect_w * vect_h);
 115     if (sub_type != AVS_I_FRAME) {
 116         int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h);
 117         init_get_bits(&change_map, table, map_size);
 118         table += map_size;
 119     }
 120
 121     for (y=0; y<198; y+=vect_h) {
 122         for (x=0; x<318; x+=vect_w) {
 123             if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) {
 124                 vect = &buf[*table++ * (vect_w * vect_h)];
 125                 for (j=0; j<vect_w; j++) {
 126                     out[(y + 0) * stride + x + j] = vect[(0 * vect_w) + j];
 127                     out[(y + 1) * stride + x + j] = vect[(1 * vect_w) + j];
 128                     if (vect_h == 3)
 129                         out[(y + 2) * stride + x + j] =
 130                             vect[(2 * vect_w) + j];
 131                 }
 132             }
 133         }
 134         if (sub_type != AVS_I_FRAME)
 135             align_get_bits(&change_map);
 136     }
 137
 138     *picture = *(AVFrame *) & avs->picture;
 139     *data_size = sizeof(AVPicture);
 140
 141     return buf_size;
 142 }
 143
 144 static int avs_decode_init(AVCodecContext * avctx)
 145 {
 146     avctx->pix_fmt = PIX_FMT_PAL8;
 147     return 0;
 148 }
 149
 150 AVCodec avs_decoder = {
 151     "avs",
 152     CODEC_TYPE_VIDEO,
 153     CODEC_ID_AVS,
 154     sizeof(avs_context_t),
 155     avs_decode_init,
 156     NULL,
 157     NULL,
 158     avs_decode_frame,
 159     CODEC_CAP_DR1,
 160 };