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 "get_bits.h"
25 #include "internal.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
avs_decode_frame(AVCodecContext * avctx,AVFrame * picture,int * got_frame,AVPacket * avpkt)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->key_frame = 0;
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->key_frame = 1;
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
avs_decode_init(AVCodecContext * avctx)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
avs_decode_end(AVCodecContext * avctx)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 .p.long_name = NULL_IF_CONFIG_SMALL("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 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
189 };
190