FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/rtjpeg.c
Date: 2021-09-26 18:22:30
Exec Total Coverage
Lines: 66 70 94.3%
Branches: 46 56 82.1%

Line Branch Exec Source
1 /*
2 * RTJpeg decoding functions
3 * Copyright (c) 2006 Reimar Doeffinger
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 #include "libavutil/common.h"
22 #include "get_bits.h"
23 #include "rtjpeg.h"
24
25 #define PUT_COEFF(c) \
26 i = scan[coeff--]; \
27 block[i] = (c) * quant[i];
28
29 /// aligns the bitstream to the given power of two
30 #define ALIGN(a) \
31 n = (-get_bits_count(gb)) & (a - 1); \
32 if (n) {skip_bits(gb, n);}
33
34 /**
35 * @brief read one block from stream
36 * @param gb contains stream data
37 * @param block where data is written to
38 * @param scan array containing the mapping stream address -> block position
39 * @param quant quantization factors
40 * @return 0 means the block is not coded, < 0 means an error occurred.
41 *
42 * Note: GetBitContext is used to make the code simpler, since all data is
43 * aligned this could be done faster in a different way, e.g. as it is done
44 * in MPlayer libmpcodecs/native/rtjpegn.c.
45 */
46 223200 static inline int get_block(GetBitContext *gb, int16_t *block, const uint8_t *scan,
47 const uint32_t *quant) {
48 int coeff, i, n;
49 int8_t ac;
50 223200 uint8_t dc = get_bits(gb, 8);
51
52 // block not coded
53
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223200 if (dc == 255)
54 102402 return 0;
55
56 // number of non-zero coefficients
57 120798 coeff = get_bits(gb, 6);
58
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120798 if (get_bits_left(gb) < (coeff << 1))
59 return AVERROR_INVALIDDATA;
60
61 // normally we would only need to clear the (63 - coeff) last values,
62 // but since we do not know where they are we just clear the whole block
63 120798 memset(block, 0, 64 * sizeof(int16_t));
64
65 // 2 bits per coefficient
66
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755404 while (coeff) {
67 691920 ac = get_sbits(gb, 2);
68
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691920 if (ac == -2)
69 57314 break; // continue with more bits
70 634606 PUT_COEFF(ac);
71 }
72
73 // 4 bits per coefficient
74
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120798 ALIGN(4);
75
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120798 if (get_bits_left(gb) < (coeff << 2))
76 return AVERROR_INVALIDDATA;
77
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545462 while (coeff) {
78 451590 ac = get_sbits(gb, 4);
79
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451590 if (ac == -8)
80 26926 break; // continue with more bits
81 424664 PUT_COEFF(ac);
82 }
83
84 // 8 bits per coefficient
85
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120798 ALIGN(8);
86
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120798 if (get_bits_left(gb) < (coeff << 3))
87 return AVERROR_INVALIDDATA;
88
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274357 while (coeff) {
89 153559 ac = get_sbits(gb, 8);
90 153559 PUT_COEFF(ac);
91 }
92
93 120798 PUT_COEFF(dc);
94 120798 return 1;
95 }
96
97 /**
98 * @brief decode one rtjpeg YUV420 frame
99 * @param c context, must be initialized via ff_rtjpeg_decode_init
100 * @param f AVFrame to place decoded frame into. If parts of the frame
101 * are not coded they are left unchanged, so consider initializing it
102 * @param buf buffer containing input data
103 * @param buf_size length of input data in bytes
104 * @return number of bytes consumed from the input buffer
105 */
106 57 int ff_rtjpeg_decode_frame_yuv420(RTJpegContext *c, AVFrame *f,
107 const uint8_t *buf, int buf_size) {
108 GetBitContext gb;
109 57 int w = c->w / 16, h = c->h / 16;
110 int x, y, ret;
111 57 uint8_t *y1 = f->data[0], *y2 = f->data[0] + 8 * f->linesize[0];
112 57 uint8_t *u = f->data[1], *v = f->data[2];
113
114
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57 if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
115 return ret;
116
117
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1167 for (y = 0; y < h; y++) {
118
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38310 for (x = 0; x < w; x++) {
119 #define BLOCK(quant, dst, stride) do { \
120 int res = get_block(&gb, block, c->scan, quant); \
121 if (res < 0) \
122 return res; \
123 if (res > 0) \
124 c->idsp.idct_put(dst, stride, block); \
125 } while (0)
126 37200 int16_t *block = c->block;
127
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37200 BLOCK(c->lquant, y1, f->linesize[0]);
128 37200 y1 += 8;
129
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37200 BLOCK(c->lquant, y1, f->linesize[0]);
130 37200 y1 += 8;
131
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37200 BLOCK(c->lquant, y2, f->linesize[0]);
132 37200 y2 += 8;
133
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37200 BLOCK(c->lquant, y2, f->linesize[0]);
134 37200 y2 += 8;
135
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37200 BLOCK(c->cquant, u, f->linesize[1]);
136 37200 u += 8;
137
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37200 BLOCK(c->cquant, v, f->linesize[2]);
138 37200 v += 8;
139 }
140 1110 y1 += 2 * 8 * (f->linesize[0] - w);
141 1110 y2 += 2 * 8 * (f->linesize[0] - w);
142 1110 u += 8 * (f->linesize[1] - w);
143 1110 v += 8 * (f->linesize[2] - w);
144 }
145 57 return get_bits_count(&gb) / 8;
146 }
147
148 /**
149 * @brief initialize an RTJpegContext, may be called multiple times
150 * @param c context to initialize
151 * @param width width of image, will be rounded down to the nearest multiple
152 * of 16 for decoding
153 * @param height height of image, will be rounded down to the nearest multiple
154 * of 16 for decoding
155 * @param lquant luma quantization table to use
156 * @param cquant chroma quantization table to use
157 */
158 54 void ff_rtjpeg_decode_init(RTJpegContext *c, int width, int height,
159 const uint32_t *lquant, const uint32_t *cquant) {
160 int i;
161
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3510 for (i = 0; i < 64; i++) {
162 3456 int p = c->idsp.idct_permutation[i];
163 3456 c->lquant[p] = lquant[i];
164 3456 c->cquant[p] = cquant[i];
165 }
166 54 c->w = width;
167 54 c->h = height;
168 54 }
169
170 4 void ff_rtjpeg_init(RTJpegContext *c, AVCodecContext *avctx)
171 {
172 int i;
173
174 4 ff_idctdsp_init(&c->idsp, avctx);
175
176
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260 for (i = 0; i < 64; i++) {
177 256 int z = ff_zigzag_direct[i];
178 256 z = ((z << 3) | (z >> 3)) & 63; // rtjpeg uses a transposed variant
179
180 // permute the scan and quantization tables for the chosen idct
181 256 c->scan[i] = c->idsp.idct_permutation[z];
182 }
183 4 }
184