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#include "internal.h" 25 26 27typedef struct { 28 AVFrame *frame; 29} AvsContext; 30 31typedef enum { 32 AVS_VIDEO = 0x01, 33 AVS_AUDIO = 0x02, 34 AVS_PALETTE = 0x03, 35 AVS_GAME_DATA = 0x04, 36} AvsBlockType; 37 38typedef 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 46static int 47avs_decode_frame(AVCodecContext * avctx, 48 void *data, int *got_frame, AVPacket *avpkt) 49{ 50 const uint8_t *buf = avpkt->data; 51 const uint8_t *buf_end = avpkt->data + avpkt->size; 52 int buf_size = avpkt->size; 53 AvsContext *const avs = avctx->priv_data; 54 AVFrame *picture = data; 55 AVFrame *const p = avs->frame; 56 const uint8_t *table, *vect; 57 uint8_t *out; 58 int i, j, x, y, stride, ret, vect_w = 3, vect_h = 3; 59 AvsVideoSubType sub_type; 60 AvsBlockType type; 61 GetBitContext change_map = {0}; //init to silence warning 62 63 if ((ret = ff_reget_buffer(avctx, p)) < 0) 64 return ret; 65 p->pict_type = AV_PICTURE_TYPE_P; 66 p->key_frame = 0; 67 68 out = p->data[0]; 69 stride = p->linesize[0]; 70 71 if (buf_end - buf < 4) 72 return AVERROR_INVALIDDATA; 73 sub_type = buf[0]; 74 type = buf[1]; 75 buf += 4; 76 77 if (type == AVS_PALETTE) { 78 int first, last; 79 uint32_t *pal = (uint32_t *) p->data[1]; 80 81 first = AV_RL16(buf); 82 last = first + AV_RL16(buf + 2); 83 if (first >= 256 || last > 256 || buf_end - buf < 4 + 4 + 3 * (last - first)) 84 return AVERROR_INVALIDDATA; 85 buf += 4; 86 for (i=first; i<last; i++, buf+=3) { 87 pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2); 88 pal[i] |= 0xFFU << 24 | (pal[i] >> 6) & 0x30303; 89 } 90 91 sub_type = buf[0]; 92 type = buf[1]; 93 buf += 4; 94 } 95 96 if (type != AVS_VIDEO) 97 return AVERROR_INVALIDDATA; 98 99 switch (sub_type) { 100 case AVS_I_FRAME: 101 p->pict_type = AV_PICTURE_TYPE_I; 102 p->key_frame = 1; 103 case AVS_P_FRAME_3X3: 104 vect_w = 3; 105 vect_h = 3; 106 break; 107 108 case AVS_P_FRAME_2X2: 109 vect_w = 2; 110 vect_h = 2; 111 break; 112 113 case AVS_P_FRAME_2X3: 114 vect_w = 2; 115 vect_h = 3; 116 break; 117 118 default: 119 return AVERROR_INVALIDDATA; 120 } 121 122 if (buf_end - buf < 256 * vect_w * vect_h) 123 return AVERROR_INVALIDDATA; 124 table = buf + (256 * vect_w * vect_h); 125 if (sub_type != AVS_I_FRAME) { 126 int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h); 127 if (buf_end - table < map_size) 128 return AVERROR_INVALIDDATA; 129 init_get_bits(&change_map, table, map_size * 8); 130 table += map_size; 131 } 132 133 for (y=0; y<198; y+=vect_h) { 134 for (x=0; x<318; x+=vect_w) { 135 if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) { 136 if (buf_end - table < 1) 137 return AVERROR_INVALIDDATA; 138 vect = &buf[*table++ * (vect_w * vect_h)]; 139 for (j=0; j<vect_w; j++) { 140 out[(y + 0) * stride + x + j] = vect[(0 * vect_w) + j]; 141 out[(y + 1) * stride + x + j] = vect[(1 * vect_w) + j]; 142 if (vect_h == 3) 143 out[(y + 2) * stride + x + j] = 144 vect[(2 * vect_w) + j]; 145 } 146 } 147 } 148 if (sub_type != AVS_I_FRAME) 149 align_get_bits(&change_map); 150 } 151 152 if ((ret = av_frame_ref(picture, p)) < 0) 153 return ret; 154 *got_frame = 1; 155 156 return buf_size; 157} 158 159static av_cold int avs_decode_init(AVCodecContext * avctx) 160{ 161 AvsContext *s = avctx->priv_data; 162 163 s->frame = av_frame_alloc(); 164 if (!s->frame) 165 return AVERROR(ENOMEM); 166 167 avctx->pix_fmt = AV_PIX_FMT_PAL8; 168 ff_set_dimensions(avctx, 318, 198); 169 170 return 0; 171} 172 173static av_cold int avs_decode_end(AVCodecContext *avctx) 174{ 175 AvsContext *s = avctx->priv_data; 176 av_frame_free(&s->frame); 177 return 0; 178} 179 180 181AVCodec ff_avs_decoder = { 182 .name = "avs", 183 .long_name = NULL_IF_CONFIG_SMALL("AVS (Audio Video Standard) video"), 184 .type = AVMEDIA_TYPE_VIDEO, 185 .id = AV_CODEC_ID_AVS, 186 .priv_data_size = sizeof(AvsContext), 187 .init = avs_decode_init, 188 .decode = avs_decode_frame, 189 .close = avs_decode_end, 190 .capabilities = CODEC_CAP_DR1, 191}; 192