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"
37 #include "codec_internal.h"
40 #define MM_PREAMBLE_SIZE 6
42 #define MM_TYPE_INTER 0x5
43 #define MM_TYPE_INTRA 0x8
44 #define MM_TYPE_INTRA_HH 0xc
45 #define MM_TYPE_INTER_HH 0xd
46 #define MM_TYPE_INTRA_HHV 0xe
47 #define MM_TYPE_INTER_HHV 0xf
48 #define MM_TYPE_PALETTE 0x31
50 typedef struct MmContext {
51 AVCodecContext *avctx;
53 unsigned int palette[AVPALETTE_COUNT];
57 static av_cold int mm_decode_init(AVCodecContext *avctx)
59 MmContext *s = avctx->priv_data;
63 avctx->pix_fmt = AV_PIX_FMT_PAL8;
65 if (!avctx->width || !avctx->height ||
66 (avctx->width & 1) || (avctx->height & 1)) {
67 av_log(avctx, AV_LOG_ERROR, "Invalid video dimensions: %dx%d\n",
68 avctx->width, avctx->height);
69 return AVERROR(EINVAL);
72 s->frame = av_frame_alloc();
74 return AVERROR(ENOMEM);
79 static void mm_decode_pal(MmContext *s)
83 bytestream2_skip(&s->gb, 4);
84 for (i = 0; i < 128; i++) {
85 s->palette[i] = 0xFFU << 24 | bytestream2_get_be24(&s->gb);
86 s->palette[i+128] = s->palette[i]<<2;
91 * @param half_horiz Half horizontal resolution (0 or 1)
92 * @param half_vert Half vertical resolution (0 or 1)
94 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
98 while (bytestream2_get_bytes_left(&s->gb) > 0) {
99 int run_length, color;
101 if (y >= s->avctx->height)
104 color = bytestream2_get_byte(&s->gb);
108 run_length = (color & 0x7f) + 2;
109 color = bytestream2_get_byte(&s->gb);
115 if (run_length > s->avctx->width - x)
116 return AVERROR_INVALIDDATA;
119 memset(s->frame->data[0] + y*s->frame->linesize[0] + x, color, run_length);
120 if (half_vert && y + half_vert < s->avctx->height)
121 memset(s->frame->data[0] + (y+1)*s->frame->linesize[0] + x, color, run_length);
125 if (x >= s->avctx->width) {
135 * @param half_horiz Half horizontal resolution (0 or 1)
136 * @param half_vert Half vertical resolution (0 or 1)
138 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
140 int data_off = bytestream2_get_le16(&s->gb);
142 GetByteContext data_ptr;
144 if (bytestream2_get_bytes_left(&s->gb) < data_off)
145 return AVERROR_INVALIDDATA;
147 bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
148 while (s->gb.buffer < data_ptr.buffer_start) {
150 int length = bytestream2_get_byte(&s->gb);
151 int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
159 if (y + half_vert >= s->avctx->height)
162 for(i=0; i<length; i++) {
163 int replace_array = bytestream2_get_byte(&s->gb);
165 int replace = (replace_array >> (7-j)) & 1;
166 if (x + half_horiz >= s->avctx->width)
167 return AVERROR_INVALIDDATA;
169 int color = bytestream2_get_byte(&data_ptr);
170 s->frame->data[0][y*s->frame->linesize[0] + x] = color;
172 s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color;
174 s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color;
176 s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color;
189 static int mm_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
190 int *got_frame, AVPacket *avpkt)
192 const uint8_t *buf = avpkt->data;
193 int buf_size = avpkt->size;
194 MmContext *s = avctx->priv_data;
197 if (buf_size < MM_PREAMBLE_SIZE)
198 return AVERROR_INVALIDDATA;
199 type = AV_RL16(&buf[0]);
200 buf += MM_PREAMBLE_SIZE;
201 buf_size -= MM_PREAMBLE_SIZE;
202 bytestream2_init(&s->gb, buf, buf_size);
204 if ((res = ff_reget_buffer(avctx, s->frame, 0)) < 0)
208 case MM_TYPE_PALETTE : mm_decode_pal(s); return avpkt->size;
209 case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
210 case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
211 case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
212 case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
213 case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
214 case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
216 res = AVERROR_INVALIDDATA;
222 memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);
224 if ((res = av_frame_ref(rframe, s->frame)) < 0)
232 static av_cold int mm_decode_end(AVCodecContext *avctx)
234 MmContext *s = avctx->priv_data;
236 av_frame_free(&s->frame);
241 const FFCodec ff_mmvideo_decoder = {
243 CODEC_LONG_NAME("American Laser Games MM Video"),
244 .p.type = AVMEDIA_TYPE_VIDEO,
245 .p.id = AV_CODEC_ID_MMVIDEO,
246 .priv_data_size = sizeof(MmContext),
247 .init = mm_decode_init,
248 .close = mm_decode_end,
249 FF_CODEC_DECODE_CB(mm_decode_frame),
250 .p.capabilities = AV_CODEC_CAP_DR1,