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 "get_bits.h"
  24
  25
  26 typedef struct {
  27     AVFrame picture;
  28 } AvsContext;
  29
  30 typedef enum {
  31     AVS_VIDEO     = 0x01,
  32     AVS_AUDIO     = 0x02,
  33     AVS_PALETTE   = 0x03,
  34     AVS_GAME_DATA = 0x04,
  35 } AvsBlockType;
  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 } AvsVideoSubType;
  43
  44
  45 static int
  46 avs_decode_frame(AVCodecContext * avctx,
  47                  void *data, int *data_size, AVPacket *avpkt)
  48 {
  49     const uint8_t *buf = avpkt->data;
  50     int buf_size = avpkt->size;
  51     AvsContext *const avs = avctx->priv_data;
  52     AVFrame *picture = data;
  53     AVFrame *const p = (AVFrame *) & avs->picture;
  54     const uint8_t *table, *vect;
  55     uint8_t *out;
  56     int i, j, x, y, stride, vect_w = 3, vect_h = 3;
  57     AvsVideoSubType sub_type;
  58     AvsBlockType type;
  59     GetBitContext change_map;
  60
  61     if (avctx->reget_buffer(avctx, p)) {
  62         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  63         return -1;
  64     }
  65     p->reference = 1;
  66     p->pict_type = FF_P_TYPE;
  67     p->key_frame = 0;
  68
  69     out = avs->picture.data[0];
  70     stride = avs->picture.linesize[0];
  71
  72     sub_type = buf[0];
  73     type = buf[1];
  74     buf += 4;
  75
  76     if (type == AVS_PALETTE) {
  77         int first, last;
  78         uint32_t *pal = (uint32_t *) avs->picture.data[1];
  79
  80         first = AV_RL16(buf);
  81         last = first + AV_RL16(buf + 2);
  82         buf += 4;
  83         for (i=first; i<last; i++, buf+=3)
  84             pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2);
  85
  86         sub_type = buf[0];
  87         type = buf[1];
  88         buf += 4;
  89     }
  90
  91     if (type != AVS_VIDEO)
  92         return -1;
  93
  94     switch (sub_type) {
  95     case AVS_I_FRAME:
  96         p->pict_type = FF_I_TYPE;
  97         p->key_frame = 1;
  98     case AVS_P_FRAME_3X3:
  99         vect_w = 3;
 100         vect_h = 3;
 101         break;
 102
 103     case AVS_P_FRAME_2X2:
 104         vect_w = 2;
 105         vect_h = 2;
 106         break;
 107
 108     case AVS_P_FRAME_2X3:
 109         vect_w = 2;
 110         vect_h = 3;
 111         break;
 112
 113     default:
 114       return -1;
 115     }
 116
 117     table = buf + (256 * vect_w * vect_h);
 118     if (sub_type != AVS_I_FRAME) {
 119         int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h);
 120         init_get_bits(&change_map, table, map_size);
 121         table += map_size;
 122     }
 123
 124     for (y=0; y<198; y+=vect_h) {
 125         for (x=0; x<318; x+=vect_w) {
 126             if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) {
 127                 vect = &buf[*table++ * (vect_w * vect_h)];
 128                 for (j=0; j<vect_w; j++) {
 129                     out[(y + 0) * stride + x + j] = vect[(0 * vect_w) + j];
 130                     out[(y + 1) * stride + x + j] = vect[(1 * vect_w) + j];
 131                     if (vect_h == 3)
 132                         out[(y + 2) * stride + x + j] =
 133                             vect[(2 * vect_w) + j];
 134                 }
 135             }
 136         }
 137         if (sub_type != AVS_I_FRAME)
 138             align_get_bits(&change_map);
 139     }
 140
 141     *picture = *(AVFrame *) & avs->picture;
 142     *data_size = sizeof(AVPicture);
 143
 144     return buf_size;
 145 }
 146
 147 static av_cold int avs_decode_init(AVCodecContext * avctx)
 148 {
 149     avctx->pix_fmt = PIX_FMT_PAL8;
 150     return 0;
 151 }
 152
 153 AVCodec avs_decoder = {
 154     "avs",
 155     CODEC_TYPE_VIDEO,
 156     CODEC_ID_AVS,
 157     sizeof(AvsContext),
 158     avs_decode_init,
 159     NULL,
 160     NULL,
 161     avs_decode_frame,
 162     CODEC_CAP_DR1,
 163     .long_name = NULL_IF_CONFIG_SMALL("AVS (Audio Video Standard) video"),
 164 };