FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/kmvc.c
Date: 2025-10-19 14:07:46
Exec Total Coverage
Lines: 122 207 58.9%
Functions: 4 4 100.0%
Branches: 90 156 57.7%
Line Branch Exec Source
1 /*
2 * KMVC decoder
3 * Copyright (c) 2006 Konstantin Shishkov
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 * Karl Morton's Video Codec decoder
25 */
26
27 #include <stdio.h>
28
29 #include "avcodec.h"
30 #include "bytestream.h"
31 #include "codec_internal.h"
32 #include "decode.h"
33 #include "libavutil/common.h"
34
35 #define KMVC_KEYFRAME 0x80
36 #define KMVC_PALETTE 0x40
37 #define KMVC_METHOD 0x0F
38 #define MAX_PALSIZE 256
39
40 /*
41 * Decoder context
42 */
43 typedef struct KmvcContext {
44 AVCodecContext *avctx;
45
46 GetByteContext g;
47 uint8_t *cur, *prev;
48 int setpal;
49 int palsize;
50 uint32_t pal[MAX_PALSIZE];
51 uint8_t frm0[320 * 200], frm1[320 * 200];
52 } KmvcContext;
53
54 typedef struct BitBuf {
55 int bits;
56 int bitbuf;
57 } BitBuf;
58
59 #define BLK(data, x, y) data[av_clip((x) + (y) * 320, 0, 320 * 200 -1)]
60
61 #define kmvc_init_getbits(bb, g) bb.bits = 7; bb.bitbuf = bytestream2_get_byte(g);
62
63 #define kmvc_getbit(bb, g, res) {\
64 res = 0; \
65 if (bb.bitbuf & (1 << bb.bits)) res = 1; \
66 bb.bits--; \
67 if(bb.bits == -1) { \
68 bb.bitbuf = bytestream2_get_byte(g); \
69 bb.bits = 7; \
70 } \
71 }
72
73 1 static int kmvc_decode_intra_8x8(KmvcContext * ctx, int w, int h)
74 {
75 BitBuf bb;
76 int res, val;
77 int i, j;
78 int bx, by;
79 int l0x, l1x, l0y, l1y;
80 int mx, my;
81
82 1 kmvc_init_getbits(bb, &ctx->g);
83
84
2/2
✓ Branch 0 taken 20 times.
✓ Branch 1 taken 1 times.
 21 for (by = 0; by < h; by += 8)
85
2/2
✓ Branch 0 taken 800 times.
✓ Branch 1 taken 20 times.
 820 for (bx = 0; bx < w; bx += 8) {
86
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 800 times.
 800 if (!bytestream2_get_bytes_left(&ctx->g)) {
87 ✗ av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
88 ✗ return AVERROR_INVALIDDATA;
89 }
90
3/4
✗ Branch 0 not taken.
✓ Branch 1 taken 800 times.
✓ Branch 2 taken 100 times.
✓ Branch 3 taken 700 times.
 800 kmvc_getbit(bb, &ctx->g, res);
91
1/2
✓ Branch 0 taken 800 times.
✗ Branch 1 not taken.
 800 if (!res) { // fill whole 8x8 block
92 800 val = bytestream2_get_byte(&ctx->g);
93
2/2
✓ Branch 0 taken 51200 times.
✓ Branch 1 taken 800 times.
 52000 for (i = 0; i < 64; i++)
94 51200 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
95 } else { // handle four 4x4 subblocks
96 ✗ for (i = 0; i < 4; i++) {
97 ✗ l0x = bx + (i & 1) * 4;
98 ✗ l0y = by + (i & 2) * 2;
99 ✗ kmvc_getbit(bb, &ctx->g, res);
100 ✗ if (!res) {
101 ✗ kmvc_getbit(bb, &ctx->g, res);
102 ✗ if (!res) { // fill whole 4x4 block
103 ✗ val = bytestream2_get_byte(&ctx->g);
104 ✗ for (j = 0; j < 16; j++)
105 ✗ BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
106 } else { // copy block from already decoded place
107 ✗ val = bytestream2_get_byte(&ctx->g);
108 ✗ mx = val & 0xF;
109 ✗ my = val >> 4;
110 ✗ if ((l0x-mx) + 320*(l0y-my) < 0 || (l0x-mx) + 320*(l0y-my) > 320*197 - 4) {
111 ✗ av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
112 ✗ return AVERROR_INVALIDDATA;
113 }
114 ✗ for (j = 0; j < 16; j++)
115 ✗ BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
116 ✗ BLK(ctx->cur, l0x + (j & 3) - mx, l0y + (j >> 2) - my);
117 }
118 } else { // descend to 2x2 sub-sub-blocks
119 ✗ for (j = 0; j < 4; j++) {
120 ✗ l1x = l0x + (j & 1) * 2;
121 ✗ l1y = l0y + (j & 2);
122 ✗ kmvc_getbit(bb, &ctx->g, res);
123 ✗ if (!res) {
124 ✗ kmvc_getbit(bb, &ctx->g, res);
125 ✗ if (!res) { // fill whole 2x2 block
126 ✗ val = bytestream2_get_byte(&ctx->g);
127 ✗ BLK(ctx->cur, l1x, l1y) = val;
128 ✗ BLK(ctx->cur, l1x + 1, l1y) = val;
129 ✗ BLK(ctx->cur, l1x, l1y + 1) = val;
130 ✗ BLK(ctx->cur, l1x + 1, l1y + 1) = val;
131 } else { // copy block from already decoded place
132 ✗ val = bytestream2_get_byte(&ctx->g);
133 ✗ mx = val & 0xF;
134 ✗ my = val >> 4;
135 ✗ if ((l1x-mx) + 320*(l1y-my) < 0 || (l1x-mx) + 320*(l1y-my) > 320*199 - 2) {
136 ✗ av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
137 ✗ return AVERROR_INVALIDDATA;
138 }
139 ✗ BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my);
140 ✗ BLK(ctx->cur, l1x + 1, l1y) =
141 ✗ BLK(ctx->cur, l1x + 1 - mx, l1y - my);
142 ✗ BLK(ctx->cur, l1x, l1y + 1) =
143 ✗ BLK(ctx->cur, l1x - mx, l1y + 1 - my);
144 ✗ BLK(ctx->cur, l1x + 1, l1y + 1) =
145 ✗ BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my);
146 }
147 } else { // read values for block
148 ✗ BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
149 ✗ BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
150 ✗ BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
151 ✗ BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
152 }
153 }
154 }
155 }
156 }
157 }
158
159 1 return 0;
160 }
161
162 77 static int kmvc_decode_inter_8x8(KmvcContext * ctx, int w, int h)
163 {
164 BitBuf bb;
165 int res, val;
166 int i, j;
167 int bx, by;
168 int l0x, l1x, l0y, l1y;
169 int mx, my;
170
171 77 kmvc_init_getbits(bb, &ctx->g);
172
173
2/2
✓ Branch 0 taken 1540 times.
✓ Branch 1 taken 77 times.
 1617 for (by = 0; by < h; by += 8)
174
2/2
✓ Branch 0 taken 61600 times.
✓ Branch 1 taken 1540 times.
 63140 for (bx = 0; bx < w; bx += 8) {
175
4/4
✓ Branch 0 taken 20351 times.
✓ Branch 1 taken 41249 times.
✓ Branch 2 taken 5816 times.
✓ Branch 3 taken 55784 times.
 61600 kmvc_getbit(bb, &ctx->g, res);
176
2/2
✓ Branch 0 taken 41249 times.
✓ Branch 1 taken 20351 times.
 61600 if (!res) {
177
4/4
✓ Branch 0 taken 1243 times.
✓ Branch 1 taken 40006 times.
✓ Branch 2 taken 7058 times.
✓ Branch 3 taken 34191 times.
 41249 kmvc_getbit(bb, &ctx->g, res);
178
2/2
✓ Branch 0 taken 40006 times.
✓ Branch 1 taken 1243 times.
 41249 if (!res) { // fill whole 8x8 block
179
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 40006 times.
 40006 if (!bytestream2_get_bytes_left(&ctx->g)) {
180 ✗ av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
181 ✗ return AVERROR_INVALIDDATA;
182 }
183 40006 val = bytestream2_get_byte(&ctx->g);
184
2/2
✓ Branch 0 taken 2560384 times.
✓ Branch 1 taken 40006 times.
 2600390 for (i = 0; i < 64; i++)
185 2560384 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
186 } else { // copy block from previous frame
187
2/2
✓ Branch 0 taken 79552 times.
✓ Branch 1 taken 1243 times.
 80795 for (i = 0; i < 64; i++)
188 79552 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) =
189 79552 BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3));
190 }
191 } else { // handle four 4x4 subblocks
192
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 20351 times.
 20351 if (!bytestream2_get_bytes_left(&ctx->g)) {
193 ✗ av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
194 ✗ return AVERROR_INVALIDDATA;
195 }
196
2/2
✓ Branch 0 taken 81404 times.
✓ Branch 1 taken 20351 times.
 101755 for (i = 0; i < 4; i++) {
197 81404 l0x = bx + (i & 1) * 4;
198 81404 l0y = by + (i & 2) * 2;
199
4/4
✓ Branch 0 taken 65350 times.
✓ Branch 1 taken 16054 times.
✓ Branch 2 taken 10252 times.
✓ Branch 3 taken 71152 times.
 81404 kmvc_getbit(bb, &ctx->g, res);
200
2/2
✓ Branch 0 taken 16054 times.
✓ Branch 1 taken 65350 times.
 81404 if (!res) {
201
4/4
✓ Branch 0 taken 9883 times.
✓ Branch 1 taken 6171 times.
✓ Branch 2 taken 1963 times.
✓ Branch 3 taken 14091 times.
 16054 kmvc_getbit(bb, &ctx->g, res);
202
2/2
✓ Branch 0 taken 6171 times.
✓ Branch 1 taken 9883 times.
 16054 if (!res) { // fill whole 4x4 block
203 6171 val = bytestream2_get_byte(&ctx->g);
204
2/2
✓ Branch 0 taken 98736 times.
✓ Branch 1 taken 6171 times.
 104907 for (j = 0; j < 16; j++)
205 98736 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
206 } else { // copy block
207 9883 val = bytestream2_get_byte(&ctx->g);
208 9883 mx = (val & 0xF) - 8;
209 9883 my = (val >> 4) - 8;
210
2/4
✓ Branch 0 taken 9883 times.
✗ Branch 1 not taken.
✗ Branch 2 not taken.
✓ Branch 3 taken 9883 times.
 9883 if ((l0x+mx) + 320*(l0y+my) < 0 || (l0x+mx) + 320*(l0y+my) > 320*197 - 4) {
211 ✗ av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
212 ✗ return AVERROR_INVALIDDATA;
213 }
214
2/2
✓ Branch 0 taken 158128 times.
✓ Branch 1 taken 9883 times.
 168011 for (j = 0; j < 16; j++)
215 158128 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
216 158128 BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my);
217 }
218 } else { // descend to 2x2 sub-sub-blocks
219
2/2
✓ Branch 0 taken 261400 times.
✓ Branch 1 taken 65350 times.
 326750 for (j = 0; j < 4; j++) {
220 261400 l1x = l0x + (j & 1) * 2;
221 261400 l1y = l0y + (j & 2);
222
4/4
✓ Branch 0 taken 130830 times.
✓ Branch 1 taken 130570 times.
✓ Branch 2 taken 32725 times.
✓ Branch 3 taken 228675 times.
 261400 kmvc_getbit(bb, &ctx->g, res);
223
2/2
✓ Branch 0 taken 130570 times.
✓ Branch 1 taken 130830 times.
 261400 if (!res) {
224
4/4
✓ Branch 0 taken 108747 times.
✓ Branch 1 taken 21823 times.
✓ Branch 2 taken 16190 times.
✓ Branch 3 taken 114380 times.
 130570 kmvc_getbit(bb, &ctx->g, res);
225
2/2
✓ Branch 0 taken 21823 times.
✓ Branch 1 taken 108747 times.
 130570 if (!res) { // fill whole 2x2 block
226 21823 val = bytestream2_get_byte(&ctx->g);
227 21823 BLK(ctx->cur, l1x, l1y) = val;
228 21823 BLK(ctx->cur, l1x + 1, l1y) = val;
229 21823 BLK(ctx->cur, l1x, l1y + 1) = val;
230 21823 BLK(ctx->cur, l1x + 1, l1y + 1) = val;
231 } else { // copy block
232 108747 val = bytestream2_get_byte(&ctx->g);
233 108747 mx = (val & 0xF) - 8;
234 108747 my = (val >> 4) - 8;
235
2/4
✓ Branch 0 taken 108747 times.
✗ Branch 1 not taken.
✗ Branch 2 not taken.
✓ Branch 3 taken 108747 times.
 108747 if ((l1x+mx) + 320*(l1y+my) < 0 || (l1x+mx) + 320*(l1y+my) > 320*199 - 2) {
236 ✗ av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
237 ✗ return AVERROR_INVALIDDATA;
238 }
239 108747 BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my);
240 108747 BLK(ctx->cur, l1x + 1, l1y) =
241 108747 BLK(ctx->prev, l1x + 1 + mx, l1y + my);
242 108747 BLK(ctx->cur, l1x, l1y + 1) =
243 108747 BLK(ctx->prev, l1x + mx, l1y + 1 + my);
244 108747 BLK(ctx->cur, l1x + 1, l1y + 1) =
245 108747 BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my);
246 }
247 } else { // read values for block
248 130830 BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
249 130830 BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
250 130830 BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
251 130830 BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
252 }
253 }
254 }
255 }
256 }
257 }
258
259 77 return 0;
260 }
261
262 78 static int decode_frame(AVCodecContext * avctx, AVFrame *frame,
263 int *got_frame, AVPacket *avpkt)
264 {
265 78 KmvcContext *const ctx = avctx->priv_data;
266 uint8_t *out, *src;
267 int i, ret;
268 int header;
269 int blocksize;
270
271 78 bytestream2_init(&ctx->g, avpkt->data, avpkt->size);
272
273
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 78 times.
 78 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
274 ✗ return ret;
275
276 78 ff_copy_palette(ctx->pal, avpkt, avctx);
277
278 78 header = bytestream2_get_byte(&ctx->g);
279
280 /* blocksize 127 is really palette change event */
281
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 78 times.
 78 if (bytestream2_peek_byte(&ctx->g) == 127) {
282 ✗ bytestream2_skip(&ctx->g, 3);
283 ✗ for (i = 0; i < 127; i++) {
284 ✗ ctx->pal[i + (header & 0x81)] = 0xFFU << 24 | bytestream2_get_be24(&ctx->g);
285 ✗ bytestream2_skip(&ctx->g, 1);
286 }
287 ✗ bytestream2_seek(&ctx->g, -127 * 4 - 3, SEEK_CUR);
288 }
289
290
2/2
✓ Branch 0 taken 1 times.
✓ Branch 1 taken 77 times.
 78 if (header & KMVC_KEYFRAME) {
291 1 frame->flags |= AV_FRAME_FLAG_KEY;
292 1 frame->pict_type = AV_PICTURE_TYPE_I;
293 } else {
294 77 frame->flags &= ~AV_FRAME_FLAG_KEY;
295 77 frame->pict_type = AV_PICTURE_TYPE_P;
296 }
297
298
2/2
✓ Branch 0 taken 1 times.
✓ Branch 1 taken 77 times.
 78 if (header & KMVC_PALETTE) {
299 // palette starts from index 1 and has 127 entries
300
2/2
✓ Branch 0 taken 255 times.
✓ Branch 1 taken 1 times.
 256 for (i = 1; i <= ctx->palsize; i++) {
301 255 ctx->pal[i] = 0xFFU << 24 | bytestream2_get_be24(&ctx->g);
302 }
303 }
304
305
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 78 times.
 78 if (ctx->setpal) {
306 ✗ ctx->setpal = 0;
307 }
308
309 /* make the palette available on the way out */
310 78 memcpy(frame->data[1], ctx->pal, 1024);
311
312 78 blocksize = bytestream2_get_byte(&ctx->g);
313
314
1/4
✗ Branch 0 not taken.
✓ Branch 1 taken 78 times.
✗ Branch 2 not taken.
✗ Branch 3 not taken.
 78 if (blocksize != 8 && blocksize != 127) {
315 ✗ av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize);
316 ✗ return AVERROR_INVALIDDATA;
317 }
318 78 memset(ctx->cur, 0, 320 * 200);
319
2/4
✗ Branch 0 not taken.
✓ Branch 1 taken 1 times.
✓ Branch 2 taken 77 times.
✗ Branch 3 not taken.
 78 switch (header & KMVC_METHOD) {
320 ✗ case 0:
321 case 1: // used in palette changed event
322 ✗ memcpy(ctx->cur, ctx->prev, 320 * 200);
323 ✗ break;
324 1 case 3:
325 1 kmvc_decode_intra_8x8(ctx, avctx->width, avctx->height);
326 1 break;
327 77 case 4:
328 77 kmvc_decode_inter_8x8(ctx, avctx->width, avctx->height);
329 77 break;
330 ✗ default:
331 ✗ av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD);
332 ✗ return AVERROR_INVALIDDATA;
333 }
334
335 78 out = frame->data[0];
336 78 src = ctx->cur;
337
2/2
✓ Branch 0 taken 12480 times.
✓ Branch 1 taken 78 times.
 12558 for (i = 0; i < avctx->height; i++) {
338 12480 memcpy(out, src, avctx->width);
339 12480 src += 320;
340 12480 out += frame->linesize[0];
341 }
342
343 /* flip buffers */
344 78 FFSWAP(uint8_t *, ctx->cur, ctx->prev);
345
346 78 *got_frame = 1;
347
348 /* always report that the buffer was completely consumed */
349 78 return avpkt->size;
350 }
351
352
353
354 /*
355 * Init kmvc decoder
356 */
357 2 static av_cold int decode_init(AVCodecContext * avctx)
358 {
359 2 KmvcContext *const c = avctx->priv_data;
360 int i;
361
362 2 c->avctx = avctx;
363
364
2/4
✓ Branch 0 taken 2 times.
✗ Branch 1 not taken.
✗ Branch 2 not taken.
✓ Branch 3 taken 2 times.
 2 if (avctx->width > 320 || avctx->height > 200) {
365 ✗ av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n");
366 ✗ return AVERROR(EINVAL);
367 }
368
369 2 c->cur = c->frm0;
370 2 c->prev = c->frm1;
371
372
2/2
✓ Branch 0 taken 512 times.
✓ Branch 1 taken 2 times.
 514 for (i = 0; i < 256; i++) {
373 512 c->pal[i] = 0xFFU << 24 | i * 0x10101;
374 }
375
376
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 2 times.
 2 if (avctx->extradata_size < 12) {
377 ✗ av_log(avctx, AV_LOG_WARNING,
378 "Extradata missing, decoding may not work properly...\n");
379 ✗ c->palsize = 127;
380 } else {
381 2 c->palsize = AV_RL16(avctx->extradata + 10);
382
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 2 times.
 2 if (c->palsize >= (unsigned)MAX_PALSIZE) {
383 ✗ c->palsize = 127;
384 ✗ av_log(avctx, AV_LOG_ERROR, "KMVC palette too large\n");
385 ✗ return AVERROR_INVALIDDATA;
386 }
387 }
388
389
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 2 times.
 2 if (avctx->extradata_size == 1036) { // palette in extradata
390 ✗ uint8_t *src = avctx->extradata + 12;
391 ✗ for (i = 0; i < 256; i++) {
392 ✗ c->pal[i] = AV_RL32(src);
393 ✗ src += 4;
394 }
395 ✗ c->setpal = 1;
396 }
397
398 2 avctx->pix_fmt = AV_PIX_FMT_PAL8;
399
400 2 return 0;
401 }
402
403 const FFCodec ff_kmvc_decoder = {
404 .p.name = "kmvc",
405 CODEC_LONG_NAME("Karl Morton's video codec"),
406 .p.type = AVMEDIA_TYPE_VIDEO,
407 .p.id = AV_CODEC_ID_KMVC,
408 .priv_data_size = sizeof(KmvcContext),
409 .init = decode_init,
410 FF_CODEC_DECODE_CB(decode_frame),
411 .p.capabilities = AV_CODEC_CAP_DR1,
412 };
413