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libavcodec/avs.c

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00001 /*
00002  * AVS video decoder.
00003  * Copyright (c) 2006  Aurelien Jacobs <aurel@gnuage.org>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "avcodec.h"
00023 #include "bitstream.h"
00024 
00025 
00026 typedef struct {
00027     AVFrame picture;
00028 } AvsContext;
00029 
00030 typedef enum {
00031     AVS_VIDEO     = 0x01,
00032     AVS_AUDIO     = 0x02,
00033     AVS_PALETTE   = 0x03,
00034     AVS_GAME_DATA = 0x04,
00035 } AvsBlockType;
00036 
00037 typedef enum {
00038     AVS_I_FRAME     = 0x00,
00039     AVS_P_FRAME_3X3 = 0x01,
00040     AVS_P_FRAME_2X2 = 0x02,
00041     AVS_P_FRAME_2X3 = 0x03,
00042 } AvsVideoSubType;
00043 
00044 
00045 static int
00046 avs_decode_frame(AVCodecContext * avctx,
00047                  void *data, int *data_size, const uint8_t * buf, int buf_size)
00048 {
00049     AvsContext *const avs = avctx->priv_data;
00050     AVFrame *picture = data;
00051     AVFrame *const p = (AVFrame *) & avs->picture;
00052     const uint8_t *table, *vect;
00053     uint8_t *out;
00054     int i, j, x, y, stride, vect_w = 3, vect_h = 3;
00055     AvsVideoSubType sub_type;
00056     AvsBlockType type;
00057     GetBitContext change_map;
00058 
00059     if (avctx->reget_buffer(avctx, p)) {
00060         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
00061         return -1;
00062     }
00063     p->reference = 1;
00064     p->pict_type = FF_P_TYPE;
00065     p->key_frame = 0;
00066 
00067     out = avs->picture.data[0];
00068     stride = avs->picture.linesize[0];
00069 
00070     sub_type = buf[0];
00071     type = buf[1];
00072     buf += 4;
00073 
00074     if (type == AVS_PALETTE) {
00075         int first, last;
00076         uint32_t *pal = (uint32_t *) avs->picture.data[1];
00077 
00078         first = AV_RL16(buf);
00079         last = first + AV_RL16(buf + 2);
00080         buf += 4;
00081         for (i=first; i<last; i++, buf+=3)
00082             pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2);
00083 
00084         sub_type = buf[0];
00085         type = buf[1];
00086         buf += 4;
00087     }
00088 
00089     if (type != AVS_VIDEO)
00090         return -1;
00091 
00092     switch (sub_type) {
00093     case AVS_I_FRAME:
00094         p->pict_type = FF_I_TYPE;
00095         p->key_frame = 1;
00096     case AVS_P_FRAME_3X3:
00097         vect_w = 3;
00098         vect_h = 3;
00099         break;
00100 
00101     case AVS_P_FRAME_2X2:
00102         vect_w = 2;
00103         vect_h = 2;
00104         break;
00105 
00106     case AVS_P_FRAME_2X3:
00107         vect_w = 2;
00108         vect_h = 3;
00109         break;
00110 
00111     default:
00112       return -1;
00113     }
00114 
00115     table = buf + (256 * vect_w * vect_h);
00116     if (sub_type != AVS_I_FRAME) {
00117         int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h);
00118         init_get_bits(&change_map, table, map_size);
00119         table += map_size;
00120     }
00121 
00122     for (y=0; y<198; y+=vect_h) {
00123         for (x=0; x<318; x+=vect_w) {
00124             if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) {
00125                 vect = &buf[*table++ * (vect_w * vect_h)];
00126                 for (j=0; j<vect_w; j++) {
00127                     out[(y + 0) * stride + x + j] = vect[(0 * vect_w) + j];
00128                     out[(y + 1) * stride + x + j] = vect[(1 * vect_w) + j];
00129                     if (vect_h == 3)
00130                         out[(y + 2) * stride + x + j] =
00131                             vect[(2 * vect_w) + j];
00132                 }
00133             }
00134         }
00135         if (sub_type != AVS_I_FRAME)
00136             align_get_bits(&change_map);
00137     }
00138 
00139     *picture = *(AVFrame *) & avs->picture;
00140     *data_size = sizeof(AVPicture);
00141 
00142     return buf_size;
00143 }
00144 
00145 static av_cold int avs_decode_init(AVCodecContext * avctx)
00146 {
00147     avctx->pix_fmt = PIX_FMT_PAL8;
00148     avcodec_set_dimensions(avctx, 318, 198);
00149     return 0;
00150 }
00151 
00152 AVCodec avs_decoder = {
00153     "avs",
00154     CODEC_TYPE_VIDEO,
00155     CODEC_ID_AVS,
00156     sizeof(AvsContext),
00157     avs_decode_init,
00158     NULL,
00159     NULL,
00160     avs_decode_frame,
00161     CODEC_CAP_DR1,
00162     .long_name = NULL_IF_CONFIG_SMALL("AVS (Audio Video Standard) video"),
00163 };

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