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