path: root/libavcodec/avs.c (plain)
blob: 66724d47b729cf3526bca606632f5b6e469cfc28

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
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)
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
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
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