2 * American Laser Games MM Video Decoder
3 * Copyright (c) 2006,2008 Peter Ross
5 * This file is part of FFmpeg.
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.
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.
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
24 * American Laser Games MM Video Decoder
25 * by Peter Ross (pross@xvid.org)
27 * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
28 * including Mad Dog McCree and Crime Patrol.
30 * Technical details here:
31 * http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
34 #include "libavutil/intreadwrite.h"
36 #include "bytestream.h"
39 #define MM_PREAMBLE_SIZE 6
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
49 typedef struct MmContext
{
50 AVCodecContext
*avctx
;
52 int palette
[AVPALETTE_COUNT
];
56 static av_cold
int mm_decode_init(AVCodecContext
*avctx
)
58 MmContext
*s
= avctx
->priv_data
;
62 avctx
->pix_fmt
= AV_PIX_FMT_PAL8
;
64 s
->frame
= av_frame_alloc();
66 return AVERROR(ENOMEM
);
71 static void mm_decode_pal(MmContext
*s
)
75 bytestream2_skip(&s
->gb
, 4);
76 for (i
= 0; i
< 128; i
++) {
77 s
->palette
[i
] = 0xFFU
<< 24 | bytestream2_get_be24(&s
->gb
);
78 s
->palette
[i
+128] = s
->palette
[i
]<<2;
83 * @param half_horiz Half horizontal resolution (0 or 1)
84 * @param half_vert Half vertical resolution (0 or 1)
86 static int mm_decode_intra(MmContext
* s
, int half_horiz
, int half_vert
)
90 while (bytestream2_get_bytes_left(&s
->gb
) > 0) {
91 int run_length
, color
;
93 if (y
>= s
->avctx
->height
)
96 color
= bytestream2_get_byte(&s
->gb
);
100 run_length
= (color
& 0x7f) + 2;
101 color
= bytestream2_get_byte(&s
->gb
);
107 if (run_length
> s
->avctx
->width
- x
)
108 return AVERROR_INVALIDDATA
;
111 memset(s
->frame
->data
[0] + y
*s
->frame
->linesize
[0] + x
, color
, run_length
);
112 if (half_vert
&& y
+ half_vert
< s
->avctx
->height
)
113 memset(s
->frame
->data
[0] + (y
+1)*s
->frame
->linesize
[0] + x
, color
, run_length
);
117 if (x
>= s
->avctx
->width
) {
127 * @param half_horiz Half horizontal resolution (0 or 1)
128 * @param half_vert Half vertical resolution (0 or 1)
130 static int mm_decode_inter(MmContext
* s
, int half_horiz
, int half_vert
)
132 int data_off
= bytestream2_get_le16(&s
->gb
);
134 GetByteContext data_ptr
;
136 if (bytestream2_get_bytes_left(&s
->gb
) < data_off
)
137 return AVERROR_INVALIDDATA
;
139 bytestream2_init(&data_ptr
, s
->gb
.buffer
+ data_off
, bytestream2_get_bytes_left(&s
->gb
) - data_off
);
140 while (s
->gb
.buffer
< data_ptr
.buffer_start
) {
142 int length
= bytestream2_get_byte(&s
->gb
);
143 int x
= bytestream2_get_byte(&s
->gb
) + ((length
& 0x80) << 1);
151 if (y
+ half_vert
>= s
->avctx
->height
)
154 for(i
=0; i
<length
; i
++) {
155 int replace_array
= bytestream2_get_byte(&s
->gb
);
157 int replace
= (replace_array
>> (7-j
)) & 1;
158 if (x
+ half_horiz
>= s
->avctx
->width
)
159 return AVERROR_INVALIDDATA
;
161 int color
= bytestream2_get_byte(&data_ptr
);
162 s
->frame
->data
[0][y
*s
->frame
->linesize
[0] + x
] = color
;
164 s
->frame
->data
[0][y
*s
->frame
->linesize
[0] + x
+ 1] = color
;
166 s
->frame
->data
[0][(y
+1)*s
->frame
->linesize
[0] + x
] = color
;
168 s
->frame
->data
[0][(y
+1)*s
->frame
->linesize
[0] + x
+ 1] = color
;
181 static int mm_decode_frame(AVCodecContext
*avctx
,
182 void *data
, int *got_frame
,
185 const uint8_t *buf
= avpkt
->data
;
186 int buf_size
= avpkt
->size
;
187 MmContext
*s
= avctx
->priv_data
;
190 if (buf_size
< MM_PREAMBLE_SIZE
)
191 return AVERROR_INVALIDDATA
;
192 type
= AV_RL16(&buf
[0]);
193 buf
+= MM_PREAMBLE_SIZE
;
194 buf_size
-= MM_PREAMBLE_SIZE
;
195 bytestream2_init(&s
->gb
, buf
, buf_size
);
197 if ((res
= ff_reget_buffer(avctx
, s
->frame
)) < 0)
201 case MM_TYPE_PALETTE
: mm_decode_pal(s
); return avpkt
->size
;
202 case MM_TYPE_INTRA
: res
= mm_decode_intra(s
, 0, 0); break;
203 case MM_TYPE_INTRA_HH
: res
= mm_decode_intra(s
, 1, 0); break;
204 case MM_TYPE_INTRA_HHV
: res
= mm_decode_intra(s
, 1, 1); break;
205 case MM_TYPE_INTER
: res
= mm_decode_inter(s
, 0, 0); break;
206 case MM_TYPE_INTER_HH
: res
= mm_decode_inter(s
, 1, 0); break;
207 case MM_TYPE_INTER_HHV
: res
= mm_decode_inter(s
, 1, 1); break;
209 res
= AVERROR_INVALIDDATA
;
215 memcpy(s
->frame
->data
[1], s
->palette
, AVPALETTE_SIZE
);
217 if ((res
= av_frame_ref(data
, s
->frame
)) < 0)
225 static av_cold
int mm_decode_end(AVCodecContext
*avctx
)
227 MmContext
*s
= avctx
->priv_data
;
229 av_frame_free(&s
->frame
);
234 AVCodec ff_mmvideo_decoder
= {
236 .long_name
= NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
237 .type
= AVMEDIA_TYPE_VIDEO
,
238 .id
= AV_CODEC_ID_MMVIDEO
,
239 .priv_data_size
= sizeof(MmContext
),
240 .init
= mm_decode_init
,
241 .close
= mm_decode_end
,
242 .decode
= mm_decode_frame
,
243 .capabilities
= CODEC_CAP_DR1
,