1/*
2 * American Laser Games MM Video Decoder
3 * Copyright (c) 2006,2008 Peter Ross
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/**
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
49typedef struct MmContext {
50    AVCodecContext *avctx;
51    AVFrame *frame;
52    int palette[AVPALETTE_COUNT];
53    GetByteContext gb;
54} MmContext;
55
56static 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    s->frame = av_frame_alloc();
65    if (!s->frame)
66        return AVERROR(ENOMEM);
67
68    return 0;
69}
70
71static int mm_decode_pal(MmContext *s)
72{
73    int i;
74
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;
79    }
80
81    return 0;
82}
83
84/**
85 * @param half_horiz Half horizontal resolution (0 or 1)
86 * @param half_vert Half vertical resolution (0 or 1)
87 */
88static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
89{
90    int x = 0, y = 0;
91
92    while (bytestream2_get_bytes_left(&s->gb) > 0) {
93        int run_length, color;
94
95        if (y >= s->avctx->height)
96            return 0;
97
98        color = bytestream2_get_byte(&s->gb);
99        if (color & 0x80) {
100            run_length = 1;
101        }else{
102            run_length = (color & 0x7f) + 2;
103            color = bytestream2_get_byte(&s->gb);
104        }
105
106        if (half_horiz)
107            run_length *=2;
108
109        if (run_length > s->avctx->width - x)
110            return AVERROR_INVALIDDATA;
111
112        if (color) {
113            memset(s->frame->data[0] + y*s->frame->linesize[0] + x, color, run_length);
114            if (half_vert)
115                memset(s->frame->data[0] + (y+1)*s->frame->linesize[0] + x, color, run_length);
116        }
117        x+= run_length;
118
119        if (x >= s->avctx->width) {
120            x=0;
121            y += 1 + half_vert;
122        }
123    }
124
125    return 0;
126}
127
128/**
129 * @param half_horiz Half horizontal resolution (0 or 1)
130 * @param half_vert Half vertical resolution (0 or 1)
131 */
132static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
133{
134    int data_off = bytestream2_get_le16(&s->gb);
135    int y = 0;
136    GetByteContext data_ptr;
137
138    if (bytestream2_get_bytes_left(&s->gb) < data_off)
139        return AVERROR_INVALIDDATA;
140
141    bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
142    while (s->gb.buffer < data_ptr.buffer_start) {
143        int i, j;
144        int length = bytestream2_get_byte(&s->gb);
145        int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
146        length &= 0x7F;
147
148        if (length==0) {
149            y += x;
150            continue;
151        }
152
153        if (y + half_vert >= s->avctx->height)
154            return 0;
155
156        for(i=0; i<length; i++) {
157            int replace_array = bytestream2_get_byte(&s->gb);
158            for(j=0; j<8; j++) {
159                int replace = (replace_array >> (7-j)) & 1;
160                if (x + half_horiz >= s->avctx->width)
161                    return AVERROR_INVALIDDATA;
162                if (replace) {
163                    int color = bytestream2_get_byte(&data_ptr);
164                    s->frame->data[0][y*s->frame->linesize[0] + x] = color;
165                    if (half_horiz)
166                        s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color;
167                    if (half_vert) {
168                        s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color;
169                        if (half_horiz)
170                            s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color;
171                    }
172                }
173                x += 1 + half_horiz;
174            }
175        }
176
177        y += 1 + half_vert;
178    }
179
180    return 0;
181}
182
183static int mm_decode_frame(AVCodecContext *avctx,
184                            void *data, int *got_frame,
185                            AVPacket *avpkt)
186{
187    const uint8_t *buf = avpkt->data;
188    int buf_size = avpkt->size;
189    MmContext *s = avctx->priv_data;
190    int type, res;
191
192    if (buf_size < MM_PREAMBLE_SIZE)
193        return AVERROR_INVALIDDATA;
194    type = AV_RL16(&buf[0]);
195    buf += MM_PREAMBLE_SIZE;
196    buf_size -= MM_PREAMBLE_SIZE;
197    bytestream2_init(&s->gb, buf, buf_size);
198
199    if ((res = ff_reget_buffer(avctx, s->frame)) < 0)
200        return res;
201
202    switch(type) {
203    case MM_TYPE_PALETTE   : res = mm_decode_pal(s); return avpkt->size;
204    case MM_TYPE_INTRA     : res = mm_decode_intra(s, 0, 0); break;
205    case MM_TYPE_INTRA_HH  : res = mm_decode_intra(s, 1, 0); break;
206    case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
207    case MM_TYPE_INTER     : res = mm_decode_inter(s, 0, 0); break;
208    case MM_TYPE_INTER_HH  : res = mm_decode_inter(s, 1, 0); break;
209    case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
210    default:
211        res = AVERROR_INVALIDDATA;
212        break;
213    }
214    if (res < 0)
215        return res;
216
217    memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);
218
219    if ((res = av_frame_ref(data, s->frame)) < 0)
220        return res;
221
222    *got_frame      = 1;
223
224    return avpkt->size;
225}
226
227static av_cold int mm_decode_end(AVCodecContext *avctx)
228{
229    MmContext *s = avctx->priv_data;
230
231    av_frame_free(&s->frame);
232
233    return 0;
234}
235
236AVCodec ff_mmvideo_decoder = {
237    .name           = "mmvideo",
238    .long_name      = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
239    .type           = AVMEDIA_TYPE_VIDEO,
240    .id             = AV_CODEC_ID_MMVIDEO,
241    .priv_data_size = sizeof(MmContext),
242    .init           = mm_decode_init,
243    .close          = mm_decode_end,
244    .decode         = mm_decode_frame,
245    .capabilities   = CODEC_CAP_DR1,
246};
247