2 * American Laser Games MM Video Decoder
3 * Copyright (c) 2006,2008 Peter Ross
5 * This file is part of Libav.
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.
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.
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
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 int mm_decode_pal(MmContext *s)
75 bytestream2_skip(&s->gb, 4);
76 for (i = 0; i < 128; i++) {
77 s->palette[i] = bytestream2_get_be24(&s->gb);
78 s->palette[i+128] = s->palette[i]<<2;
85 * @param half_horiz Half horizontal resolution (0 or 1)
86 * @param half_vert Half vertical resolution (0 or 1)
88 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
92 while (bytestream2_get_bytes_left(&s->gb) > 0) {
93 int run_length, color;
95 if (y >= s->avctx->height)
98 color = bytestream2_get_byte(&s->gb);
102 run_length = (color & 0x7f) + 2;
103 color = bytestream2_get_byte(&s->gb);
110 memset(s->frame->data[0] + y*s->frame->linesize[0] + x, color, run_length);
112 memset(s->frame->data[0] + (y+1)*s->frame->linesize[0] + x, color, run_length);
116 if (x >= s->avctx->width) {
126 * @param half_horiz Half horizontal resolution (0 or 1)
127 * @param half_vert Half vertical resolution (0 or 1)
129 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
131 int data_off = bytestream2_get_le16(&s->gb);
133 GetByteContext data_ptr;
135 if (bytestream2_get_bytes_left(&s->gb) < data_off)
136 return AVERROR_INVALIDDATA;
138 bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
139 while (s->gb.buffer < data_ptr.buffer_start) {
141 int length = bytestream2_get_byte(&s->gb);
142 int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
150 if (y + half_vert >= s->avctx->height)
153 for(i=0; i<length; i++) {
154 int replace_array = bytestream2_get_byte(&s->gb);
156 int replace = (replace_array >> (7-j)) & 1;
158 int color = bytestream2_get_byte(&data_ptr);
159 s->frame->data[0][y*s->frame->linesize[0] + x] = color;
161 s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color;
163 s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color;
165 s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color;
178 static int mm_decode_frame(AVCodecContext *avctx,
179 void *data, int *got_frame,
182 const uint8_t *buf = avpkt->data;
183 int buf_size = avpkt->size;
184 MmContext *s = avctx->priv_data;
187 if (buf_size < MM_PREAMBLE_SIZE)
188 return AVERROR_INVALIDDATA;
189 type = AV_RL16(&buf[0]);
190 buf += MM_PREAMBLE_SIZE;
191 buf_size -= MM_PREAMBLE_SIZE;
192 bytestream2_init(&s->gb, buf, buf_size);
194 if ((res = ff_reget_buffer(avctx, s->frame)) < 0) {
195 av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
200 case MM_TYPE_PALETTE : res = mm_decode_pal(s); return buf_size;
201 case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
202 case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
203 case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
204 case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
205 case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
206 case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
208 res = AVERROR_INVALIDDATA;
214 memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);
216 if ((res = av_frame_ref(data, s->frame)) < 0)
224 static av_cold int mm_decode_end(AVCodecContext *avctx)
226 MmContext *s = avctx->priv_data;
228 av_frame_free(&s->frame);
233 AVCodec ff_mmvideo_decoder = {
235 .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
236 .type = AVMEDIA_TYPE_VIDEO,
237 .id = AV_CODEC_ID_MMVIDEO,
238 .priv_data_size = sizeof(MmContext),
239 .init = mm_decode_init,
240 .close = mm_decode_end,
241 .decode = mm_decode_frame,
242 .capabilities = CODEC_CAP_DR1,