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 "codec_internal.h"
  24 #include "decode.h"
  25 #include "get_bits.h"
  26
  27 typedef struct AvsContext {
  28     AVFrame *frame;
  29 } AvsContext;
  30
  31 typedef enum {
  32     AVS_VIDEO     = 0x01,
  33     AVS_AUDIO     = 0x02,
  34     AVS_PALETTE   = 0x03,
  35     AVS_GAME_DATA = 0x04,
  36 } AvsBlockType;
  37
  38 typedef enum {
  39     AVS_I_FRAME     = 0x00,
  40     AVS_P_FRAME_3X3 = 0x01,
  41     AVS_P_FRAME_2X2 = 0x02,
  42     AVS_P_FRAME_2X3 = 0x03,
  43 } AvsVideoSubType;
  44
  45
  46 static int avs_decode_frame(AVCodecContext * avctx, AVFrame *picture,
  47                             int *got_frame, AVPacket *avpkt)
  48 {
  49     const uint8_t *buf = avpkt->data;
  50     const uint8_t *buf_end = avpkt->data + avpkt->size;
  51     int buf_size = avpkt->size;
  52     AvsContext *const avs = avctx->priv_data;
  53     AVFrame *const p =  avs->frame;
  54     const uint8_t *table, *vect;
  55     uint8_t *out;
  56     int i, j, x, y, stride, ret, vect_w = 3, vect_h = 3;
  57     AvsVideoSubType sub_type;
  58     AvsBlockType type;
  59     GetBitContext change_map = {0}; //init to silence warning
  60
  61     if ((ret = ff_reget_buffer(avctx, p, 0)) < 0)
  62         return ret;
  63     p->pict_type = AV_PICTURE_TYPE_P;
  64     p->flags &= ~AV_FRAME_FLAG_KEY;
  65
  66     out    = p->data[0];
  67     stride = p->linesize[0];
  68
  69     if (buf_end - buf < 4)
  70         return AVERROR_INVALIDDATA;
  71     sub_type = buf[0];
  72     type = buf[1];
  73     buf += 4;
  74
  75     if (type == AVS_PALETTE) {
  76         int first, last;
  77         uint32_t *pal = (uint32_t *) p->data[1];
  78
  79         first = AV_RL16(buf);
  80         last = first + AV_RL16(buf + 2);
  81         if (first >= 256 || last > 256 || buf_end - buf < 4 + 4 + 3 * (last - first))
  82             return AVERROR_INVALIDDATA;
  83         buf += 4;
  84         for (i=first; i<last; i++, buf+=3) {
  85             pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2);
  86             pal[i] |= 0xFFU << 24 | (pal[i] >> 6) & 0x30303;
  87         }
  88
  89         sub_type = buf[0];
  90         type = buf[1];
  91         buf += 4;
  92     }
  93
  94     if (type != AVS_VIDEO)
  95         return AVERROR_INVALIDDATA;
  96
  97     switch (sub_type) {
  98     case AVS_I_FRAME:
  99         p->pict_type = AV_PICTURE_TYPE_I;
 100         p->flags |= AV_FRAME_FLAG_KEY;
 101     case AVS_P_FRAME_3X3:
 102         vect_w = 3;
 103         vect_h = 3;
 104         break;
 105
 106     case AVS_P_FRAME_2X2:
 107         vect_w = 2;
 108         vect_h = 2;
 109         break;
 110
 111     case AVS_P_FRAME_2X3:
 112         vect_w = 2;
 113         vect_h = 3;
 114         break;
 115
 116     default:
 117       return AVERROR_INVALIDDATA;
 118     }
 119
 120     if (buf_end - buf < 256 * vect_w * vect_h)
 121         return AVERROR_INVALIDDATA;
 122     table = buf + (256 * vect_w * vect_h);
 123     if (sub_type != AVS_I_FRAME) {
 124         int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h);
 125         if (buf_end - table < map_size)
 126             return AVERROR_INVALIDDATA;
 127         init_get_bits(&change_map, table, map_size * 8);
 128         table += map_size;
 129     }
 130
 131     for (y=0; y<198; y+=vect_h) {
 132         for (x=0; x<318; x+=vect_w) {
 133             if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) {
 134                 if (buf_end - table < 1)
 135                     return AVERROR_INVALIDDATA;
 136                 vect = &buf[*table++ * (vect_w * vect_h)];
 137                 for (j=0; j<vect_w; j++) {
 138                     out[(y + 0) * stride + x + j] = vect[(0 * vect_w) + j];
 139                     out[(y + 1) * stride + x + j] = vect[(1 * vect_w) + j];
 140                     if (vect_h == 3)
 141                         out[(y + 2) * stride + x + j] =
 142                             vect[(2 * vect_w) + j];
 143                 }
 144             }
 145         }
 146         if (sub_type != AVS_I_FRAME)
 147             align_get_bits(&change_map);
 148     }
 149
 150     if ((ret = av_frame_ref(picture, p)) < 0)
 151         return ret;
 152     *got_frame = 1;
 153
 154     return buf_size;
 155 }
 156
 157 static av_cold int avs_decode_init(AVCodecContext * avctx)
 158 {
 159     AvsContext *s = avctx->priv_data;
 160
 161     s->frame = av_frame_alloc();
 162     if (!s->frame)
 163         return AVERROR(ENOMEM);
 164
 165     avctx->pix_fmt = AV_PIX_FMT_PAL8;
 166
 167     return ff_set_dimensions(avctx, 318, 198);
 168 }
 169
 170 static av_cold int avs_decode_end(AVCodecContext *avctx)
 171 {
 172     AvsContext *s = avctx->priv_data;
 173     av_frame_free(&s->frame);
 174     return 0;
 175 }
 176
 177
 178 const FFCodec ff_avs_decoder = {
 179     .p.name         = "avs",
 180     CODEC_LONG_NAME("AVS (Audio Video Standard) video"),
 181     .p.type         = AVMEDIA_TYPE_VIDEO,
 182     .p.id           = AV_CODEC_ID_AVS,
 183     .priv_data_size = sizeof(AvsContext),
 184     .init           = avs_decode_init,
 185     FF_CODEC_DECODE_CB(avs_decode_frame),
 186     .close          = avs_decode_end,
 187     .p.capabilities = AV_CODEC_CAP_DR1,
 188 };