FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/mmvideo.c
Date: 2026-01-23 14:02:51
Exec Total Coverage
Lines: 56 115 48.7%
Functions: 5 7 71.4%
Branches: 25 73 34.2%
Line Branch Exec Source
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 "decode.h"
39
40 #define MM_PREAMBLE_SIZE 6
41
42 #define MM_TYPE_RAW 0x2
43 #define MM_TYPE_INTER 0x5
44 #define MM_TYPE_INTRA 0x8
45 #define MM_TYPE_INTRA_HH 0xc
46 #define MM_TYPE_INTER_HH 0xd
47 #define MM_TYPE_INTRA_HHV 0xe
48 #define MM_TYPE_INTER_HHV 0xf
49 #define MM_TYPE_PALETTE 0x31
50
51 typedef struct MmContext {
52 AVCodecContext *avctx;
53 AVFrame *frame;
54 unsigned int palette[AVPALETTE_COUNT];
55 GetByteContext gb;
56 } MmContext;
57
58 2 static av_cold int mm_decode_init(AVCodecContext *avctx)
59 {
60 2 MmContext *s = avctx->priv_data;
61
62 2 s->avctx = avctx;
63
64 2 avctx->pix_fmt = AV_PIX_FMT_PAL8;
65
66
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 2 if (!avctx->width || !avctx->height ||
67
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 2 (avctx->width & 1) || (avctx->height & 1)) {
68 ✗ av_log(avctx, AV_LOG_ERROR, "Invalid video dimensions: %dx%d\n",
69 avctx->width, avctx->height);
70 ✗ return AVERROR(EINVAL);
71 }
72
73 2 s->frame = av_frame_alloc();
74
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 2 if (!s->frame)
75 ✗ return AVERROR(ENOMEM);
76
77 2 return 0;
78 }
79
80 ✗ static int mm_decode_raw(MmContext * s)
81 {
82 ✗ if (bytestream2_get_bytes_left(&s->gb) < s->avctx->width * s->avctx->height)
83 ✗ return AVERROR_INVALIDDATA;
84 ✗ for (int y = 0; y < s->avctx->height; y++)
85 ✗ bytestream2_get_buffer(&s->gb, s->frame->data[0] + y*s->frame->linesize[0], s->avctx->width);
86 ✗ return 0;
87 }
88
89 1 static void mm_decode_pal(MmContext *s)
90 {
91 1 int start = bytestream2_get_le16(&s->gb);
92 1 int count = bytestream2_get_le16(&s->gb);
93
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 129 for (int i = 0; i < count; i++)
94 128 s->palette[(start+i)&0xFF] = 0xFFU << 24 | (bytestream2_get_be24(&s->gb) << 2);
95 1 }
96
97 /**
98 * @param half_horiz Half horizontal resolution (0 or 1)
99 * @param half_vert Half vertical resolution (0 or 1)
100 */
101 31 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
102 {
103 31 int x = 0, y = 0;
104
105
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 168603 while (bytestream2_get_bytes_left(&s->gb) > 0) {
106 int run_length, color;
107
108
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 168572 if (y >= s->avctx->height)
109 ✗ return 0;
110
111 168572 color = bytestream2_get_byte(&s->gb);
112
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 168572 if (color & 0x80) {
113 92018 run_length = 1;
114 }else{
115 76554 run_length = (color & 0x7f) + 2;
116 76554 color = bytestream2_get_byte(&s->gb);
117 }
118
119
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 168572 if (half_horiz)
120 ✗ run_length *=2;
121
122
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 168572 if (run_length > s->avctx->width - x)
123 ✗ return AVERROR_INVALIDDATA;
124
125
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 168572 if (color) {
126 147172 memset(s->frame->data[0] + y*s->frame->linesize[0] + x, color, run_length);
127
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 147172 if (half_vert && y + half_vert < s->avctx->height)
128 ✗ memset(s->frame->data[0] + (y+1)*s->frame->linesize[0] + x, color, run_length);
129 }
130 168572 x+= run_length;
131
132
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 168572 if (x >= s->avctx->width) {
133 4960 x=0;
134 4960 y += 1 + half_vert;
135 }
136 }
137
138 31 return 0;
139 }
140
141 /**
142 * @param half_horiz Half horizontal resolution (0 or 1)
143 * @param half_vert Half vertical resolution (0 or 1)
144 */
145 ✗ static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
146 {
147 ✗ int data_off = bytestream2_get_le16(&s->gb);
148 ✗ int y = 0;
149 GetByteContext data_ptr;
150
151 ✗ if (bytestream2_get_bytes_left(&s->gb) < data_off)
152 ✗ return AVERROR_INVALIDDATA;
153
154 ✗ bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
155 ✗ while (s->gb.buffer < data_ptr.buffer_start) {
156 int i, j;
157 ✗ int length = bytestream2_get_byte(&s->gb);
158 ✗ int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
159 ✗ length &= 0x7F;
160
161 ✗ if (length==0) {
162 ✗ y += x;
163 ✗ continue;
164 }
165
166 ✗ if (y + half_vert >= s->avctx->height)
167 ✗ return 0;
168
169 ✗ for(i=0; i<length; i++) {
170 ✗ int replace_array = bytestream2_get_byte(&s->gb);
171 ✗ for(j=0; j<8; j++) {
172 ✗ int replace = (replace_array >> (7-j)) & 1;
173 ✗ if (x + half_horiz >= s->avctx->width)
174 ✗ break;
175 ✗ if (replace) {
176 ✗ int color = bytestream2_get_byte(&data_ptr);
177 ✗ s->frame->data[0][y*s->frame->linesize[0] + x] = color;
178 ✗ if (half_horiz)
179 ✗ s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color;
180 ✗ if (half_vert) {
181 ✗ s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color;
182 ✗ if (half_horiz)
183 ✗ s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color;
184 }
185 }
186 ✗ x += 1 + half_horiz;
187 }
188 }
189
190 ✗ y += 1 + half_vert;
191 }
192
193 ✗ return 0;
194 }
195
196 32 static int mm_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
197 int *got_frame, AVPacket *avpkt)
198 {
199 32 const uint8_t *buf = avpkt->data;
200 32 int buf_size = avpkt->size;
201 32 MmContext *s = avctx->priv_data;
202 int type, res;
203
204
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 32 if (buf_size < MM_PREAMBLE_SIZE)
205 ✗ return AVERROR_INVALIDDATA;
206 32 type = AV_RL16(&buf[0]);
207 32 buf += MM_PREAMBLE_SIZE;
208 32 buf_size -= MM_PREAMBLE_SIZE;
209 32 bytestream2_init(&s->gb, buf, buf_size);
210
211
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 32 if ((res = ff_reget_buffer(avctx, s->frame, 0)) < 0)
212 ✗ return res;
213
214
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 32 switch(type) {
215 ✗ case MM_TYPE_RAW : res = mm_decode_raw(s); break;
216 1 case MM_TYPE_PALETTE : mm_decode_pal(s); return avpkt->size;
217 31 case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
218 ✗ case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
219 ✗ case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
220 ✗ case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
221 ✗ case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
222 ✗ case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
223 ✗ default:
224 ✗ res = AVERROR_INVALIDDATA;
225 ✗ break;
226 }
227
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 31 if (res < 0)
228 ✗ return res;
229
230 31 memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);
231
232
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 31 if ((res = av_frame_ref(rframe, s->frame)) < 0)
233 ✗ return res;
234
235 31 *got_frame = 1;
236
237 31 return avpkt->size;
238 }
239
240 2 static av_cold int mm_decode_end(AVCodecContext *avctx)
241 {
242 2 MmContext *s = avctx->priv_data;
243
244 2 av_frame_free(&s->frame);
245
246 2 return 0;
247 }
248
249 const FFCodec ff_mmvideo_decoder = {
250 .p.name = "mmvideo",
251 CODEC_LONG_NAME("American Laser Games MM Video"),
252 .p.type = AVMEDIA_TYPE_VIDEO,
253 .p.id = AV_CODEC_ID_MMVIDEO,
254 .priv_data_size = sizeof(MmContext),
255 .init = mm_decode_init,
256 .close = mm_decode_end,
257 FF_CODEC_DECODE_CB(mm_decode_frame),
258 .p.capabilities = AV_CODEC_CAP_DR1,
259 };
260