FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/msvideo1.c
Date: 2026-01-16 07:34:38
Exec Total Coverage
Lines: 151 159 95.0%
Functions: 5 5 100.0%
Branches: 74 94 78.7%
Line Branch Exec Source
1 /*
2 * Microsoft Video-1 Decoder
3 * Copyright (C) 2003 The FFmpeg project
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 * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
25 * For more information about the MS Video-1 format, visit:
26 * http://www.pcisys.net/~melanson/codecs/
27 */
28
29 #include <string.h>
30
31 #include "libavutil/internal.h"
32 #include "libavutil/intreadwrite.h"
33 #include "avcodec.h"
34 #include "codec_internal.h"
35 #include "decode.h"
36
37 #define PALETTE_COUNT 256
38 #define CHECK_STREAM_PTR(n) \
39 if ((stream_ptr + n) > s->size ) { \
40 av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
41 stream_ptr + n, s->size); \
42 return; \
43 }
44
45 typedef struct Msvideo1Context {
46
47 AVCodecContext *avctx;
48 AVFrame *frame;
49
50 const unsigned char *buf;
51 int size;
52
53 int mode_8bit; /* if it's not 8-bit, it's 16-bit */
54
55 uint32_t pal[256];
56 } Msvideo1Context;
57
58 13 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
59 {
60 13 Msvideo1Context *s = avctx->priv_data;
61
62 13 s->avctx = avctx;
63
64
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 13 if (avctx->width < 4 || avctx->height < 4)
65 ✗ return AVERROR_INVALIDDATA;
66
67 /* figure out the colorspace based on the presence of a palette */
68
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 13 if (s->avctx->bits_per_coded_sample == 8) {
69 5 s->mode_8bit = 1;
70 5 avctx->pix_fmt = AV_PIX_FMT_PAL8;
71
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 5 if (avctx->extradata_size >= AVPALETTE_SIZE)
72 5 memcpy(s->pal, avctx->extradata, AVPALETTE_SIZE);
73 } else {
74 8 s->mode_8bit = 0;
75 8 avctx->pix_fmt = AV_PIX_FMT_RGB555;
76 }
77
78 13 s->frame = av_frame_alloc();
79
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 13 if (!s->frame)
80 ✗ return AVERROR(ENOMEM);
81
82 13 return 0;
83 }
84
85 148 static void msvideo1_decode_8bit(Msvideo1Context *s)
86 {
87 int block_ptr, pixel_ptr;
88 int total_blocks;
89 int pixel_x, pixel_y; /* pixel width and height iterators */
90 int block_x, block_y; /* block width and height iterators */
91 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
92 int block_inc;
93 int row_dec;
94
95 /* decoding parameters */
96 int stream_ptr;
97 unsigned char byte_a, byte_b;
98 unsigned short flags;
99 int skip_blocks;
100 unsigned char colors[8];
101 148 unsigned char *pixels = s->frame->data[0];
102 148 int stride = s->frame->linesize[0];
103
104 148 stream_ptr = 0;
105 148 skip_blocks = 0;
106 148 blocks_wide = s->avctx->width / 4;
107 148 blocks_high = s->avctx->height / 4;
108 148 total_blocks = blocks_wide * blocks_high;
109 148 block_inc = 4;
110 148 row_dec = stride + 4;
111
112
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 4008 for (block_y = blocks_high; block_y > 0; block_y--) {
113 3860 block_ptr = ((block_y * 4) - 1) * stride;
114
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 187260 for (block_x = blocks_wide; block_x > 0; block_x--) {
115 /* check if this block should be skipped */
116
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 183400 if (skip_blocks) {
117 95222 block_ptr += block_inc;
118 95222 skip_blocks--;
119 95222 total_blocks--;
120 95222 continue;
121 }
122
123 88178 pixel_ptr = block_ptr;
124
125 /* get the next two bytes in the encoded data stream */
126
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 88178 CHECK_STREAM_PTR(2);
127 88178 byte_a = s->buf[stream_ptr++];
128 88178 byte_b = s->buf[stream_ptr++];
129
130 /* check if the decode is finished */
131
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 88178 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
132 ✗ return;
133
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 88178 else if ((byte_b & 0xFC) == 0x84) {
134 /* skip code, but don't count the current block */
135 8749 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
136
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 79429 } else if (byte_b < 0x80) {
137 /* 2-color encoding */
138 11545 flags = (byte_b << 8) | byte_a;
139
140
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 11545 CHECK_STREAM_PTR(2);
141 11545 colors[0] = s->buf[stream_ptr++];
142 11545 colors[1] = s->buf[stream_ptr++];
143
144
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 57725 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
145
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 230900 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
146 184720 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
147 46180 pixel_ptr -= row_dec;
148 }
149
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 67884 } else if (byte_b >= 0x90) {
150 /* 8-color encoding */
151 57028 flags = (byte_b << 8) | byte_a;
152
153
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 57028 CHECK_STREAM_PTR(8);
154 57028 memcpy(colors, &s->buf[stream_ptr], 8);
155 57028 stream_ptr += 8;
156
157
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 285140 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
158
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 1140560 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
159 912448 pixels[pixel_ptr++] =
160 912448 colors[((pixel_y & 0x2) << 1) +
161 912448 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
162 228112 pixel_ptr -= row_dec;
163 }
164 } else {
165 /* 1-color encoding */
166 10856 colors[0] = byte_a;
167
168
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 54280 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
169
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 217120 for (pixel_x = 0; pixel_x < 4; pixel_x++)
170 173696 pixels[pixel_ptr++] = colors[0];
171 43424 pixel_ptr -= row_dec;
172 }
173 }
174
175 88178 block_ptr += block_inc;
176 88178 total_blocks--;
177 }
178 }
179
180 /* make the palette available on the way out */
181
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 148 if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)
182 148 memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
183 }
184
185 180 static void msvideo1_decode_16bit(Msvideo1Context *s)
186 {
187 int block_ptr, pixel_ptr;
188 int total_blocks;
189 int pixel_x, pixel_y; /* pixel width and height iterators */
190 int block_x, block_y; /* block width and height iterators */
191 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
192 int block_inc;
193 int row_dec;
194
195 /* decoding parameters */
196 int stream_ptr;
197 unsigned char byte_a, byte_b;
198 unsigned short flags;
199 int skip_blocks;
200 unsigned short colors[8];
201 180 unsigned short *pixels = (unsigned short *)s->frame->data[0];
202 180 int stride = s->frame->linesize[0] / 2;
203
204 180 stream_ptr = 0;
205 180 skip_blocks = 0;
206 180 blocks_wide = s->avctx->width / 4;
207 180 blocks_high = s->avctx->height / 4;
208 180 total_blocks = blocks_wide * blocks_high;
209 180 block_inc = 4;
210 180 row_dec = stride + 4;
211
212
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 12090 for (block_y = blocks_high; block_y > 0; block_y--) {
213 11910 block_ptr = ((block_y * 4) - 1) * stride;
214
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 1003380 for (block_x = blocks_wide; block_x > 0; block_x--) {
215 /* check if this block should be skipped */
216
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 991470 if (skip_blocks) {
217 281140 block_ptr += block_inc;
218 281140 skip_blocks--;
219 281140 total_blocks--;
220 281140 continue;
221 }
222
223 710330 pixel_ptr = block_ptr;
224
225 /* get the next two bytes in the encoded data stream */
226
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 710330 CHECK_STREAM_PTR(2);
227 710330 byte_a = s->buf[stream_ptr++];
228 710330 byte_b = s->buf[stream_ptr++];
229
230 /* check if the decode is finished */
231
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 710330 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
232 ✗ return;
233
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 710330 } else if ((byte_b & 0xFC) == 0x84) {
234 /* skip code, but don't count the current block */
235 108271 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
236
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 602059 } else if (byte_b < 0x80) {
237 /* 2- or 8-color encoding modes */
238 280291 flags = (byte_b << 8) | byte_a;
239
240
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 280291 CHECK_STREAM_PTR(4);
241 280291 colors[0] = AV_RL16(&s->buf[stream_ptr]);
242 280291 stream_ptr += 2;
243 280291 colors[1] = AV_RL16(&s->buf[stream_ptr]);
244 280291 stream_ptr += 2;
245
246
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 280291 if (colors[0] & 0x8000) {
247 /* 8-color encoding */
248
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 145448 CHECK_STREAM_PTR(12);
249 145448 colors[2] = AV_RL16(&s->buf[stream_ptr]);
250 145448 stream_ptr += 2;
251 145448 colors[3] = AV_RL16(&s->buf[stream_ptr]);
252 145448 stream_ptr += 2;
253 145448 colors[4] = AV_RL16(&s->buf[stream_ptr]);
254 145448 stream_ptr += 2;
255 145448 colors[5] = AV_RL16(&s->buf[stream_ptr]);
256 145448 stream_ptr += 2;
257 145448 colors[6] = AV_RL16(&s->buf[stream_ptr]);
258 145448 stream_ptr += 2;
259 145448 colors[7] = AV_RL16(&s->buf[stream_ptr]);
260 145448 stream_ptr += 2;
261
262
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 727240 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
263
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 2908960 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
264 2327168 pixels[pixel_ptr++] =
265 2327168 colors[((pixel_y & 0x2) << 1) +
266 2327168 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
267 581792 pixel_ptr -= row_dec;
268 }
269 } else {
270 /* 2-color encoding */
271
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272
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 2696860 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
273 2157488 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
274 539372 pixel_ptr -= row_dec;
275 }
276 }
277 } else {
278 /* otherwise, it's a 1-color block */
279 321768 colors[0] = (byte_b << 8) | byte_a;
280
281
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282
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 6435360 for (pixel_x = 0; pixel_x < 4; pixel_x++)
283 5148288 pixels[pixel_ptr++] = colors[0];
284 1287072 pixel_ptr -= row_dec;
285 }
286 }
287
288 710330 block_ptr += block_inc;
289 710330 total_blocks--;
290 }
291 }
292 }
293
294 328 static int msvideo1_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
295 int *got_frame, AVPacket *avpkt)
296 {
297 328 const uint8_t *buf = avpkt->data;
298 328 int buf_size = avpkt->size;
299 328 Msvideo1Context *s = avctx->priv_data;
300 int ret;
301
302 328 s->buf = buf;
303 328 s->size = buf_size;
304
305 // Discard frame if its smaller than the minimum frame size
306
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 328 if (buf_size < (avctx->width/4) * (avctx->height/4) / 512) {
307 ✗ av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
308 ✗ return AVERROR_INVALIDDATA;
309 }
310
311
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 328 if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
312 ✗ return ret;
313
314
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 328 if (s->mode_8bit) {
315 148 ff_copy_palette(s->pal, avpkt, avctx);
316 }
317
318
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 328 if (s->mode_8bit)
319 148 msvideo1_decode_8bit(s);
320 else
321 180 msvideo1_decode_16bit(s);
322
323
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 328 if ((ret = av_frame_ref(rframe, s->frame)) < 0)
324 ✗ return ret;
325
326 328 *got_frame = 1;
327
328 /* report that the buffer was completely consumed */
329 328 return buf_size;
330 }
331
332 13 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
333 {
334 13 Msvideo1Context *s = avctx->priv_data;
335
336 13 av_frame_free(&s->frame);
337
338 13 return 0;
339 }
340
341 const FFCodec ff_msvideo1_decoder = {
342 .p.name = "msvideo1",
343 CODEC_LONG_NAME("Microsoft Video 1"),
344 .p.type = AVMEDIA_TYPE_VIDEO,
345 .p.id = AV_CODEC_ID_MSVIDEO1,
346 .priv_data_size = sizeof(Msvideo1Context),
347 .init = msvideo1_decode_init,
348 .close = msvideo1_decode_end,
349 FF_CODEC_DECODE_CB(msvideo1_decode_frame),
350 .p.capabilities = AV_CODEC_CAP_DR1,
351 };
352