FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/mlp_parser.c
Date: 2025-07-18 13:13:50
Exec Total Coverage
Lines: 69 86 80.2%
Functions: 2 2 100.0%
Branches: 44 60 73.3%
Line Branch Exec Source
1 /*
2 * MLP parser
3 * Copyright (c) 2007 Ian Caulfield
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 * MLP parser
25 */
26
27 #include <stdint.h>
28
29 #include "libavutil/internal.h"
30 #include "get_bits.h"
31 #include "parser.h"
32 #include "mlp_parse.h"
33 #include "mlp.h"
34
35 typedef struct MLPParseContext
36 {
37 ParseContext pc;
38
39 int bytes_left;
40
41 int in_sync;
42
43 int num_substreams;
44 } MLPParseContext;
45
46 9 static av_cold int mlp_init(AVCodecParserContext *s)
47 {
48 9 ff_mlp_init_crc();
49 9 return 0;
50 }
51
52 33479 static int mlp_parse(AVCodecParserContext *s,
53 AVCodecContext *avctx,
54 const uint8_t **poutbuf, int *poutbuf_size,
55 const uint8_t *buf, int buf_size)
56 {
57 33479 MLPParseContext *mp = s->priv_data;
58 int sync_present;
59 uint8_t parity_bits;
60 int next;
61 int ret;
62 33479 int i, p = 0;
63
64 33479 s->key_frame = 0;
65
66 33479 *poutbuf_size = 0;
67 33479 *poutbuf = NULL;
68
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 33479 if (buf_size == 0)
69 9 return 0;
70
71
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 33470 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
72 ✗ next = buf_size;
73 } else {
74
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 33470 if (!mp->in_sync) {
75 // Not in sync - find a major sync header
76
77
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 7152 for (i = 0; i < buf_size; i++) {
78 7146 mp->pc.state = (mp->pc.state << 8) | buf[i];
79
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 7146 if ((mp->pc.state & 0xfffffffe) == 0xf8726fba &&
80 // ignore if we do not have the data for the start of header
81
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 9 mp->pc.index + i >= 7) {
82 9 mp->in_sync = 1;
83 9 mp->bytes_left = 0;
84 9 break;
85 }
86 }
87
88
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 15 if (!mp->in_sync) {
89
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 6 if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1)
90 ✗ av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");
91 6 return buf_size;
92 }
93
94
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 9 if ((ret = ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size)) < 0) {
95 ✗ av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");
96 ✗ return ret;
97 }
98
99 9 return i - 7;
100 }
101
102
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 33455 if (mp->bytes_left == 0) {
103 // Find length of this packet
104
105 /* Copy overread bytes from last frame into buffer. */
106
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 29359 for(; mp->pc.overread>0; mp->pc.overread--) {
107 ✗ mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++];
108 }
109
110
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 29359 if (mp->pc.index + buf_size < 2) {
111 ✗ if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1)
112 ✗ av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");
113 ✗ return buf_size;
114 }
115
116
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 29359 mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8)
117
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 29359 | (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]);
118 29359 mp->bytes_left = (mp->bytes_left & 0xfff) * 2;
119
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 29359 if (mp->bytes_left <= 0) { // prevent infinite loop
120 ✗ goto lost_sync;
121 }
122 29359 mp->bytes_left -= mp->pc.index;
123 }
124
125
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 33455 next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left;
126
127
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 33455 if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) {
128 4102 mp->bytes_left -= buf_size;
129 4102 return buf_size;
130 }
131
132 29353 mp->bytes_left = 0;
133 }
134
135
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 29353 sync_present = buf_size >= 8 && (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba;
136
137
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 29353 if (!sync_present) {
138 /* The first nibble of a frame is a parity check of the 4-byte
139 * access unit header and all the 2- or 4-byte substream headers. */
140 // Only check when this isn't a sync frame - syncs have a checksum.
141
142 26471 s->key_frame = 0;
143
144 26471 parity_bits = 0;
145
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 90942 for (i = -1; i < mp->num_substreams; i++) {
146 64471 parity_bits ^= buf[p++];
147 64471 parity_bits ^= buf[p++];
148
149
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 64471 if (i < 0 || buf[p-2] & 0x80) {
150 26639 parity_bits ^= buf[p++];
151 26639 parity_bits ^= buf[p++];
152 }
153 }
154
155
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 26471 if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) {
156 ✗ av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n");
157 ✗ goto lost_sync;
158 }
159 } else {
160 GetBitContext gb;
161 MLPHeaderInfo mh;
162
163 2882 init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);
164
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 2882 if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)
165 ✗ goto lost_sync;
166
167 2882 s->key_frame = 1;
168
169 2882 avctx->bits_per_raw_sample = mh.group1_bits;
170
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 2882 if (avctx->bits_per_raw_sample > 16)
171 652 avctx->sample_fmt = AV_SAMPLE_FMT_S32;
172 else
173 2230 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
174 2882 avctx->sample_rate = mh.group1_samplerate;
175 2882 avctx->frame_size =
176 2882 s->duration = mh.access_unit_size;
177
178 2882 av_channel_layout_uninit(&avctx->ch_layout);
179
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 2882 if (mh.stream_type == 0xbb) {
180 /* MLP stream */
181 2230 av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_mlp);
182 } else { /* mh.stream_type == 0xba */
183 /* TrueHD stream */
184
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 652 if (!mh.channels_thd_stream2) {
185 ✗ av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_thd_stream1);
186 } else {
187 652 av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_thd_stream2);
188 }
189 }
190
191
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 2882 if (!mh.is_vbr) /* Stream is CBR */
192 ✗ avctx->bit_rate = mh.peak_bitrate;
193
194 2882 mp->num_substreams = mh.num_substreams;
195 }
196
197 29353 *poutbuf = buf;
198 29353 *poutbuf_size = buf_size;
199
200 29353 return next;
201
202 ✗ lost_sync:
203 ✗ mp->in_sync = 0;
204 ✗ return 1;
205 }
206
207 const AVCodecParser ff_mlp_parser = {
208 .codec_ids = { AV_CODEC_ID_MLP, AV_CODEC_ID_TRUEHD },
209 .priv_data_size = sizeof(MLPParseContext),
210 .parser_init = mlp_init,
211 .parser_parse = mlp_parse,
212 .parser_close = ff_parse_close,
213 };
214