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 typedef struct AvsContext {
27 AVFrame *frame;
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
avs_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)46 avs_decode_frame(AVCodecContext * avctx,
47 void *data, 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 *picture = data;
54 AVFrame *const p = avs->frame;
55 const uint8_t *table, *vect;
56 uint8_t *out;
57 int i, j, x, y, stride, ret, vect_w = 3, vect_h = 3;
58 AvsVideoSubType sub_type;
59 AvsBlockType type;
60 GetBitContext change_map = {0}; //init to silence warning
61
62 if ((ret = ff_reget_buffer(avctx, p, 0)) < 0)
63 return ret;
64 p->pict_type = AV_PICTURE_TYPE_P;
65 p->key_frame = 0;
66
67 out = p->data[0];
68 stride = p->linesize[0];
69
70 if (buf_end - buf < 4)
71 return AVERROR_INVALIDDATA;
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 *) p->data[1];
79
80 first = AV_RL16(buf);
81 last = first + AV_RL16(buf + 2);
82 if (first >= 256 || last > 256 || buf_end - buf < 4 + 4 + 3 * (last - first))
83 return AVERROR_INVALIDDATA;
84 buf += 4;
85 for (i=first; i<last; i++, buf+=3) {
86 pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2);
87 pal[i] |= 0xFFU << 24 | (pal[i] >> 6) & 0x30303;
88 }
89
90 sub_type = buf[0];
91 type = buf[1];
92 buf += 4;
93 }
94
95 if (type != AVS_VIDEO)
96 return AVERROR_INVALIDDATA;
97
98 switch (sub_type) {
99 case AVS_I_FRAME:
100 p->pict_type = AV_PICTURE_TYPE_I;
101 p->key_frame = 1;
102 case AVS_P_FRAME_3X3:
103 vect_w = 3;
104 vect_h = 3;
105 break;
106
107 case AVS_P_FRAME_2X2:
108 vect_w = 2;
109 vect_h = 2;
110 break;
111
112 case AVS_P_FRAME_2X3:
113 vect_w = 2;
114 vect_h = 3;
115 break;
116
117 default:
118 return AVERROR_INVALIDDATA;
119 }
120
121 if (buf_end - buf < 256 * vect_w * vect_h)
122 return AVERROR_INVALIDDATA;
123 table = buf + (256 * vect_w * vect_h);
124 if (sub_type != AVS_I_FRAME) {
125 int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h);
126 if (buf_end - table < map_size)
127 return AVERROR_INVALIDDATA;
128 init_get_bits(&change_map, table, map_size * 8);
129 table += map_size;
130 }
131
132 for (y=0; y<198; y+=vect_h) {
133 for (x=0; x<318; x+=vect_w) {
134 if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) {
135 if (buf_end - table < 1)
136 return AVERROR_INVALIDDATA;
137 vect = &buf[*table++ * (vect_w * vect_h)];
138 for (j=0; j<vect_w; j++) {
139 out[(y + 0) * stride + x + j] = vect[(0 * vect_w) + j];
140 out[(y + 1) * stride + x + j] = vect[(1 * vect_w) + j];
141 if (vect_h == 3)
142 out[(y + 2) * stride + x + j] =
143 vect[(2 * vect_w) + j];
144 }
145 }
146 }
147 if (sub_type != AVS_I_FRAME)
148 align_get_bits(&change_map);
149 }
150
151 if ((ret = av_frame_ref(picture, p)) < 0)
152 return ret;
153 *got_frame = 1;
154
155 return buf_size;
156 }
157
avs_decode_init(AVCodecContext * avctx)158 static av_cold int avs_decode_init(AVCodecContext * avctx)
159 {
160 AvsContext *s = avctx->priv_data;
161
162 s->frame = av_frame_alloc();
163 if (!s->frame)
164 return AVERROR(ENOMEM);
165
166 avctx->pix_fmt = AV_PIX_FMT_PAL8;
167
168 return ff_set_dimensions(avctx, 318, 198);
169 }
170
avs_decode_end(AVCodecContext * avctx)171 static av_cold int avs_decode_end(AVCodecContext *avctx)
172 {
173 AvsContext *s = avctx->priv_data;
174 av_frame_free(&s->frame);
175 return 0;
176 }
177
178
179 AVCodec ff_avs_decoder = {
180 .name = "avs",
181 .long_name = NULL_IF_CONFIG_SMALL("AVS (Audio Video Standard) video"),
182 .type = AVMEDIA_TYPE_VIDEO,
183 .id = AV_CODEC_ID_AVS,
184 .priv_data_size = sizeof(AvsContext),
185 .init = avs_decode_init,
186 .decode = avs_decode_frame,
187 .close = avs_decode_end,
188 .capabilities = AV_CODEC_CAP_DR1,
189 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
190 };
191