xref: /third_party/ffmpeg/libavcodec/mmvideo.c (revision cabdff1a) 
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 "codec_internal.h"
38#include "internal.h"
39
40#define MM_PREAMBLE_SIZE    6
41
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
49
50typedef struct MmContext {
51    AVCodecContext *avctx;
52    AVFrame *frame;
53    unsigned int palette[AVPALETTE_COUNT];
54    GetByteContext gb;
55} MmContext;
56
57static av_cold int mm_decode_init(AVCodecContext *avctx)
58{
59    MmContext *s = avctx->priv_data;
60
61    s->avctx = avctx;
62
63    avctx->pix_fmt = AV_PIX_FMT_PAL8;
64
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);
70    }
71
72    s->frame = av_frame_alloc();
73    if (!s->frame)
74        return AVERROR(ENOMEM);
75
76    return 0;
77}
78
79static void mm_decode_pal(MmContext *s)
80{
81    int i;
82
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;
87    }
88}
89
90/**
91 * @param half_horiz Half horizontal resolution (0 or 1)
92 * @param half_vert Half vertical resolution (0 or 1)
93 */
94static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
95{
96    int x = 0, y = 0;
97
98    while (bytestream2_get_bytes_left(&s->gb) > 0) {
99        int run_length, color;
100
101        if (y >= s->avctx->height)
102            return 0;
103
104        color = bytestream2_get_byte(&s->gb);
105        if (color & 0x80) {
106            run_length = 1;
107        }else{
108            run_length = (color & 0x7f) + 2;
109            color = bytestream2_get_byte(&s->gb);
110        }
111
112        if (half_horiz)
113            run_length *=2;
114
115        if (run_length > s->avctx->width - x)
116            return AVERROR_INVALIDDATA;
117
118        if (color) {
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);
122        }
123        x+= run_length;
124
125        if (x >= s->avctx->width) {
126            x=0;
127            y += 1 + half_vert;
128        }
129    }
130
131    return 0;
132}
133
134/**
135 * @param half_horiz Half horizontal resolution (0 or 1)
136 * @param half_vert Half vertical resolution (0 or 1)
137 */
138static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
139{
140    int data_off = bytestream2_get_le16(&s->gb);
141    int y = 0;
142    GetByteContext data_ptr;
143
144    if (bytestream2_get_bytes_left(&s->gb) < data_off)
145        return AVERROR_INVALIDDATA;
146
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) {
149        int i, j;
150        int length = bytestream2_get_byte(&s->gb);
151        int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
152        length &= 0x7F;
153
154        if (length==0) {
155            y += x;
156            continue;
157        }
158
159        if (y + half_vert >= s->avctx->height)
160            return 0;
161
162        for(i=0; i<length; i++) {
163            int replace_array = bytestream2_get_byte(&s->gb);
164            for(j=0; j<8; j++) {
165                int replace = (replace_array >> (7-j)) & 1;
166                if (x + half_horiz >= s->avctx->width)
167                    return AVERROR_INVALIDDATA;
168                if (replace) {
169                    int color = bytestream2_get_byte(&data_ptr);
170                    s->frame->data[0][y*s->frame->linesize[0] + x] = color;
171                    if (half_horiz)
172                        s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color;
173                    if (half_vert) {
174                        s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color;
175                        if (half_horiz)
176                            s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color;
177                    }
178                }
179                x += 1 + half_horiz;
180            }
181        }
182
183        y += 1 + half_vert;
184    }
185
186    return 0;
187}
188
189static int mm_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
190                           int *got_frame, AVPacket *avpkt)
191{
192    const uint8_t *buf = avpkt->data;
193    int buf_size = avpkt->size;
194    MmContext *s = avctx->priv_data;
195    int type, res;
196
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);
203
204    if ((res = ff_reget_buffer(avctx, s->frame, 0)) < 0)
205        return res;
206
207    switch(type) {
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;
215    default:
216        res = AVERROR_INVALIDDATA;
217        break;
218    }
219    if (res < 0)
220        return res;
221
222    memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);
223
224    if ((res = av_frame_ref(rframe, s->frame)) < 0)
225        return res;
226
227    *got_frame      = 1;
228
229    return avpkt->size;
230}
231
232static av_cold int mm_decode_end(AVCodecContext *avctx)
233{
234    MmContext *s = avctx->priv_data;
235
236    av_frame_free(&s->frame);
237
238    return 0;
239}
240
241const FFCodec ff_mmvideo_decoder = {
242    .p.name         = "mmvideo",
243    .p.long_name    = NULL_IF_CONFIG_SMALL("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,
251    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
252};
253