1da104c6709da05c7c7223231c5d394a5e195bf6
[libav.git] / libavcodec / mmvideo.c
1 /*
2 * American Laser Games MM Video Decoder
3 * Copyright (c) 2006,2008 Peter Ross
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * American Laser Games MM Video Decoder
25 * by Peter Ross (pross@xvid.org)
26 *
27 * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
28 * including Mad Dog McCree and Crime Patrol.
29 *
30 * Technical details here:
31 * http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
32 */
33
34 #include "libavutil/intreadwrite.h"
35 #include "avcodec.h"
36 #include "bytestream.h"
37 #include "internal.h"
38
39 #define MM_PREAMBLE_SIZE 6
40
41 #define MM_TYPE_INTER 0x5
42 #define MM_TYPE_INTRA 0x8
43 #define MM_TYPE_INTRA_HH 0xc
44 #define MM_TYPE_INTER_HH 0xd
45 #define MM_TYPE_INTRA_HHV 0xe
46 #define MM_TYPE_INTER_HHV 0xf
47 #define MM_TYPE_PALETTE 0x31
48
49 typedef struct MmContext {
50 AVCodecContext *avctx;
51 AVFrame frame;
52 int palette[AVPALETTE_COUNT];
53 GetByteContext gb;
54 } MmContext;
55
56 static av_cold int mm_decode_init(AVCodecContext *avctx)
57 {
58 MmContext *s = avctx->priv_data;
59
60 s->avctx = avctx;
61
62 avctx->pix_fmt = AV_PIX_FMT_PAL8;
63
64 avcodec_get_frame_defaults(&s->frame);
65
66 return 0;
67 }
68
69 static int mm_decode_pal(MmContext *s)
70 {
71 int i;
72
73 bytestream2_skip(&s->gb, 4);
74 for (i = 0; i < 128; i++) {
75 s->palette[i] = bytestream2_get_be24(&s->gb);
76 s->palette[i+128] = s->palette[i]<<2;
77 }
78
79 return 0;
80 }
81
82 /**
83 * @param half_horiz Half horizontal resolution (0 or 1)
84 * @param half_vert Half vertical resolution (0 or 1)
85 */
86 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
87 {
88 int x = 0, y = 0;
89
90 while (bytestream2_get_bytes_left(&s->gb) > 0) {
91 int run_length, color;
92
93 if (y >= s->avctx->height)
94 return 0;
95
96 color = bytestream2_get_byte(&s->gb);
97 if (color & 0x80) {
98 run_length = 1;
99 }else{
100 run_length = (color & 0x7f) + 2;
101 color = bytestream2_get_byte(&s->gb);
102 }
103
104 if (half_horiz)
105 run_length *=2;
106
107 if (color) {
108 memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
109 if (half_vert)
110 memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
111 }
112 x+= run_length;
113
114 if (x >= s->avctx->width) {
115 x=0;
116 y += 1 + half_vert;
117 }
118 }
119
120 return 0;
121 }
122
123 /*
124 * @param half_horiz Half horizontal resolution (0 or 1)
125 * @param half_vert Half vertical resolution (0 or 1)
126 */
127 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
128 {
129 int data_off = bytestream2_get_le16(&s->gb), y;
130 GetByteContext data_ptr;
131
132 if (bytestream2_get_bytes_left(&s->gb) < data_off)
133 return AVERROR_INVALIDDATA;
134
135 bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
136 while (s->gb.buffer < data_ptr.buffer_start) {
137 int i, j;
138 int length = bytestream2_get_byte(&s->gb);
139 int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
140 length &= 0x7F;
141
142 if (length==0) {
143 y += x;
144 continue;
145 }
146
147 if (y + half_vert >= s->avctx->height)
148 return 0;
149
150 for(i=0; i<length; i++) {
151 int replace_array = bytestream2_get_byte(&s->gb);
152 for(j=0; j<8; j++) {
153 int replace = (replace_array >> (7-j)) & 1;
154 if (replace) {
155 int color = bytestream2_get_byte(&data_ptr);
156 s->frame.data[0][y*s->frame.linesize[0] + x] = color;
157 if (half_horiz)
158 s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
159 if (half_vert) {
160 s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
161 if (half_horiz)
162 s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
163 }
164 }
165 x += 1 + half_horiz;
166 }
167 }
168
169 y += 1 + half_vert;
170 }
171
172 return 0;
173 }
174
175 static int mm_decode_frame(AVCodecContext *avctx,
176 void *data, int *got_frame,
177 AVPacket *avpkt)
178 {
179 const uint8_t *buf = avpkt->data;
180 int buf_size = avpkt->size;
181 MmContext *s = avctx->priv_data;
182 int type, res;
183
184 if (buf_size < MM_PREAMBLE_SIZE)
185 return AVERROR_INVALIDDATA;
186 type = AV_RL16(&buf[0]);
187 buf += MM_PREAMBLE_SIZE;
188 buf_size -= MM_PREAMBLE_SIZE;
189 bytestream2_init(&s->gb, buf, buf_size);
190
191 if ((res = ff_reget_buffer(avctx, &s->frame)) < 0) {
192 av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
193 return res;
194 }
195
196 switch(type) {
197 case MM_TYPE_PALETTE : res = mm_decode_pal(s); return buf_size;
198 case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
199 case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
200 case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
201 case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
202 case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
203 case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
204 default:
205 res = AVERROR_INVALIDDATA;
206 break;
207 }
208 if (res < 0)
209 return res;
210
211 memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
212
213 if ((res = av_frame_ref(data, &s->frame)) < 0)
214 return res;
215
216 *got_frame = 1;
217
218 return buf_size;
219 }
220
221 static av_cold int mm_decode_end(AVCodecContext *avctx)
222 {
223 MmContext *s = avctx->priv_data;
224
225 av_frame_unref(&s->frame);
226
227 return 0;
228 }
229
230 AVCodec ff_mmvideo_decoder = {
231 .name = "mmvideo",
232 .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
233 .type = AVMEDIA_TYPE_VIDEO,
234 .id = AV_CODEC_ID_MMVIDEO,
235 .priv_data_size = sizeof(MmContext),
236 .init = mm_decode_init,
237 .close = mm_decode_end,
238 .decode = mm_decode_frame,
239 .capabilities = CODEC_CAP_DR1,
240 };