FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/c93.c
Date: 2026-05-03 13:33:45
Exec Total Coverage
Lines: 106 126 84.1%
Functions: 5 5 100.0%
Branches: 58 80 72.5%
Line Branch Exec Source
1 /*
2 * Interplay C93 video decoder
3 * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
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 #include "avcodec.h"
23 #include "bytestream.h"
24 #include "codec_internal.h"
25 #include "decode.h"
26 #include "libavutil/attributes.h"
27
28 typedef struct C93DecoderContext {
29 AVFrame *pictures[2];
30 int currentpic;
31 } C93DecoderContext;
32
33 typedef enum {
34 C93_8X8_FROM_PREV = 0x02,
35 C93_4X4_FROM_PREV = 0x06,
36 C93_4X4_FROM_CURR = 0x07,
37 C93_8X8_2COLOR = 0x08,
38 C93_4X4_2COLOR = 0x0A,
39 C93_4X4_4COLOR_GRP = 0x0B,
40 C93_4X4_4COLOR = 0x0D,
41 C93_NOOP = 0x0E,
42 C93_8X8_INTRA = 0x0F,
43 } C93BlockType;
44
45 #define WIDTH 320
46 #define HEIGHT 192
47
48 #define C93_HAS_PALETTE 0x01
49 #define C93_FIRST_FRAME 0x02
50
51 2 static av_cold int decode_end(AVCodecContext *avctx)
52 {
53 2 C93DecoderContext * const c93 = avctx->priv_data;
54
55 2 av_frame_free(&c93->pictures[0]);
56 2 av_frame_free(&c93->pictures[1]);
57
58 2 return 0;
59 }
60
61 2 static av_cold int decode_init(AVCodecContext *avctx)
62 {
63 2 C93DecoderContext *s = avctx->priv_data;
64 2 avctx->pix_fmt = AV_PIX_FMT_PAL8;
65
66 2 s->pictures[0] = av_frame_alloc();
67 2 s->pictures[1] = av_frame_alloc();
68
2/4
✓ Branch 0 taken 2 times.
✗ Branch 1 not taken.
✗ Branch 2 not taken.
✓ Branch 3 taken 2 times.
 2 if (!s->pictures[0] || !s->pictures[1])
69 ✗ return AVERROR(ENOMEM);
70
71 2 return 0;
72 }
73
74 91637 static inline int copy_block(AVCodecContext *avctx, uint8_t *to,
75 uint8_t *from, int offset, int height, int stride)
76 {
77 int i;
78 91637 int width = height;
79 91637 int from_x = offset % WIDTH;
80 91637 int from_y = offset / WIDTH;
81 91637 int overflow = from_x + width - WIDTH;
82
83
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 91637 times.
 91637 if (!from) {
84 /* silently ignoring predictive blocks in first frame */
85 ✗ return 0;
86 }
87
88
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 91637 times.
 91637 if (from_y + height > HEIGHT) {
89 ✗ av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n",
90 offset);
91 ✗ return AVERROR_INVALIDDATA;
92 }
93
94
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 91637 times.
 91637 if (overflow > 0) {
95 ✗ width -= overflow;
96 ✗ for (i = 0; i < height; i++) {
97 ✗ memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow);
98 }
99 }
100
101
2/2
✓ Branch 0 taken 443432 times.
✓ Branch 1 taken 91637 times.
 535069 for (i = 0; i < height; i++) {
102 443432 memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width);
103 }
104
105 91637 return 0;
106 }
107
108 2488 static inline void draw_n_color(uint8_t *out, int stride, int width,
109 int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col)
110 {
111 int x, y;
112
2/2
✓ Branch 0 taken 8656 times.
✓ Branch 1 taken 2488 times.
 11144 for (y = 0; y < height; y++) {
113
2/2
✓ Branch 0 taken 480 times.
✓ Branch 1 taken 8176 times.
 8656 if (grps)
114 480 cols[0] = grps[3 * (y >> 1)];
115
2/2
✓ Branch 0 taken 36352 times.
✓ Branch 1 taken 8656 times.
 45008 for (x = 0; x < width; x++) {
116
2/2
✓ Branch 0 taken 1920 times.
✓ Branch 1 taken 34432 times.
 36352 if (grps)
117 1920 cols[1]= grps[(x >> 1) + 1];
118 36352 out[x + y*stride] = cols[col & ((1 << bpp) - 1)];
119 36352 col >>= bpp;
120 }
121 }
122 2488 }
123
124 42 static int decode_frame(AVCodecContext *avctx, AVFrame *rframe,
125 int *got_frame, AVPacket *avpkt)
126 {
127 42 const uint8_t *buf = avpkt->data;
128 42 int buf_size = avpkt->size;
129 42 C93DecoderContext * const c93 = avctx->priv_data;
130 42 AVFrame * const newpic = c93->pictures[c93->currentpic];
131 42 AVFrame * const oldpic = c93->pictures[c93->currentpic^1];
132 GetByteContext gb;
133 uint8_t *out;
134 42 int ret, i, x, y, b, bt = 0;
135 ptrdiff_t stride;
136
137
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 42 times.
 42 if ((ret = ff_set_dimensions(avctx, WIDTH, HEIGHT)) < 0)
138 ✗ return ret;
139
140 42 c93->currentpic ^= 1;
141
142
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 42 times.
 42 if ((ret = ff_reget_buffer(avctx, newpic, 0)) < 0)
143 ✗ return ret;
144
145 42 stride = newpic->linesize[0];
146
147 42 bytestream2_init(&gb, buf, buf_size);
148 42 b = bytestream2_get_byte(&gb);
149
2/2
✓ Branch 0 taken 1 times.
✓ Branch 1 taken 41 times.
 42 if (b & C93_FIRST_FRAME) {
150 1 newpic->pict_type = AV_PICTURE_TYPE_I;
151 1 newpic->flags |= AV_FRAME_FLAG_KEY;
152 } else {
153 41 newpic->pict_type = AV_PICTURE_TYPE_P;
154 41 newpic->flags &= ~AV_FRAME_FLAG_KEY;
155 }
156
157
2/2
✓ Branch 0 taken 1008 times.
✓ Branch 1 taken 42 times.
 1050 for (y = 0; y < HEIGHT; y += 8) {
158 1008 out = newpic->data[0] + y * stride;
159
2/2
✓ Branch 0 taken 40320 times.
✓ Branch 1 taken 1008 times.
 41328 for (x = 0; x < WIDTH; x += 8) {
160 40320 uint8_t *copy_from = oldpic->data[0];
161 uint8_t cols[4], grps[4];
162 C93BlockType block_type;
163
164
2/2
✓ Branch 0 taken 20160 times.
✓ Branch 1 taken 20160 times.
 40320 if (!bt)
165 20160 bt = bytestream2_get_byte(&gb);
166
167 40320 block_type= bt & 0x0F;
168
6/8
✓ Branch 0 taken 19221 times.
✓ Branch 1 taken 621 times.
✓ Branch 2 taken 17483 times.
✓ Branch 3 taken 54 times.
✓ Branch 4 taken 514 times.
✗ Branch 5 not taken.
✓ Branch 6 taken 2427 times.
✗ Branch 7 not taken.
 40320 switch (block_type) {
169 19221 case C93_8X8_FROM_PREV: {
170 19221 int offset = bytestream2_get_le16(&gb);
171
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 19221 times.
 19221 if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0)
172 ✗ return ret;
173 19221 break;
174 }
175
176 621 case C93_4X4_FROM_CURR:
177 621 copy_from = newpic->data[0];
178 av_fallthrough;
179 18104 case C93_4X4_FROM_PREV:
180
2/2
✓ Branch 0 taken 36208 times.
✓ Branch 1 taken 18104 times.
 54312 for (int j = 0; j < 8; j += 4) {
181
2/2
✓ Branch 0 taken 72416 times.
✓ Branch 1 taken 36208 times.
 108624 for (i = 0; i < 8; i += 4) {
182 72416 int offset = bytestream2_get_le16(&gb);
183 72416 int from_x = offset % WIDTH;
184 72416 int from_y = offset / WIDTH;
185
3/4
✓ Branch 0 taken 2484 times.
✓ Branch 1 taken 69932 times.
✗ Branch 2 not taken.
✓ Branch 3 taken 2484 times.
 72416 if (block_type == C93_4X4_FROM_CURR && from_y == y+j &&
186 ✗ (FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) {
187 ✗ avpriv_request_sample(avctx, "block overlap %d %d %d %d", from_x, x+i, from_y, y+j);
188 ✗ return AVERROR_INVALIDDATA;
189 }
190
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 72416 times.
 72416 if ((ret = copy_block(avctx, &out[j*stride+i],
191 copy_from, offset, 4, stride)) < 0)
192 ✗ return ret;
193 }
194 }
195 18104 break;
196
197 54 case C93_8X8_2COLOR:
198 54 bytestream2_get_buffer(&gb, cols, 2);
199
2/2
✓ Branch 0 taken 432 times.
✓ Branch 1 taken 54 times.
 486 for (i = 0; i < 8; i++) {
200 432 draw_n_color(out + i*stride, stride, 8, 1, 1, cols,
201 NULL, bytestream2_get_byte(&gb));
202 }
203
204 54 break;
205
206 514 case C93_4X4_2COLOR:
207 case C93_4X4_4COLOR:
208 case C93_4X4_4COLOR_GRP:
209
2/2
✓ Branch 0 taken 1028 times.
✓ Branch 1 taken 514 times.
 1542 for (int j = 0; j < 8; j += 4) {
210
2/2
✓ Branch 0 taken 2056 times.
✓ Branch 1 taken 1028 times.
 3084 for (i = 0; i < 8; i += 4) {
211
2/2
✓ Branch 0 taken 104 times.
✓ Branch 1 taken 1952 times.
 2056 if (block_type == C93_4X4_2COLOR) {
212 104 bytestream2_get_buffer(&gb, cols, 2);
213 104 draw_n_color(out + i + j*stride, stride, 4, 4,
214 1, cols, NULL, bytestream2_get_le16(&gb));
215
2/2
✓ Branch 0 taken 1832 times.
✓ Branch 1 taken 120 times.
 1952 } else if (block_type == C93_4X4_4COLOR) {
216 1832 bytestream2_get_buffer(&gb, cols, 4);
217 1832 draw_n_color(out + i + j*stride, stride, 4, 4,
218 2, cols, NULL, bytestream2_get_le32(&gb));
219 } else {
220 120 bytestream2_get_buffer(&gb, grps, 4);
221 120 draw_n_color(out + i + j*stride, stride, 4, 4,
222 1, cols, grps, bytestream2_get_le16(&gb));
223 }
224 }
225 }
226 514 break;
227
228 ✗ case C93_NOOP:
229 ✗ break;
230
231 2427 case C93_8X8_INTRA:
232
2/2
✓ Branch 0 taken 19416 times.
✓ Branch 1 taken 2427 times.
 21843 for (int j = 0; j < 8; j++)
233 19416 bytestream2_get_buffer(&gb, out + j*stride, 8);
234 2427 break;
235
236 ✗ default:
237 ✗ av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n",
238 block_type, x, y);
239 ✗ return AVERROR_INVALIDDATA;
240 }
241 40320 bt >>= 4;
242 40320 out += 8;
243 }
244 }
245
246
2/2
✓ Branch 0 taken 1 times.
✓ Branch 1 taken 41 times.
 42 if (b & C93_HAS_PALETTE) {
247 1 uint32_t *palette = (uint32_t *) newpic->data[1];
248
2/2
✓ Branch 0 taken 256 times.
✓ Branch 1 taken 1 times.
 257 for (i = 0; i < 256; i++) {
249 256 palette[i] = 0xFFU << 24 | bytestream2_get_be24(&gb);
250 }
251 } else {
252
1/2
✓ Branch 0 taken 41 times.
✗ Branch 1 not taken.
 41 if (oldpic->data[1])
253 41 memcpy(newpic->data[1], oldpic->data[1], 256 * 4);
254 }
255
256
1/2
✗ Branch 1 not taken.
✓ Branch 2 taken 42 times.
 42 if ((ret = av_frame_ref(rframe, newpic)) < 0)
257 ✗ return ret;
258 42 *got_frame = 1;
259
260 42 return buf_size;
261 }
262
263 const FFCodec ff_c93_decoder = {
264 .p.name = "c93",
265 CODEC_LONG_NAME("Interplay C93"),
266 .p.type = AVMEDIA_TYPE_VIDEO,
267 .p.id = AV_CODEC_ID_C93,
268 .priv_data_size = sizeof(C93DecoderContext),
269 .init = decode_init,
270 .close = decode_end,
271 FF_CODEC_DECODE_CB(decode_frame),
272 .p.capabilities = AV_CODEC_CAP_DR1,
273 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
274 };
275