FFmpeg
mlp.c
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1 /*
2  * MLP codec common code
3  * Copyright (c) 2007-2008 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 #include <stdint.h>
23 
25 #include "libavutil/crc.h"
26 #include "libavutil/intreadwrite.h"
27 #include "libavutil/thread.h"
28 #include "mlp.h"
29 
30 const uint8_t ff_mlp_huffman_tables[3][18][2] = {
31  { /* Huffman table 0, -7 - +10 */
32  {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
33  {0x04, 3}, {0x05, 3}, {0x06, 3}, {0x07, 3},
34  {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
35  }, { /* Huffman table 1, -7 - +8 */
36  {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
37  {0x02, 2}, {0x03, 2},
38  {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
39  }, { /* Huffman table 2, -7 - +7 */
40  {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
41  {0x01, 1},
42  {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
43  }
44 };
45 
47  { 0x01, 0x01, 0x00, 0x1f }, { 0x03, 0x02, 0x00, 0x1b },
48  { 0x07, 0x02, 0x01, 0x1f }, { 0x0F, 0x02, 0x02, 0x19 },
49  { 0x07, 0x02, 0x01, 0x03 }, { 0x0F, 0x02, 0x02, 0x1f },
50  { 0x1F, 0x02, 0x03, 0x01 }, { 0x07, 0x02, 0x01, 0x1a },
51  { 0x0F, 0x02, 0x02, 0x1f }, { 0x1F, 0x02, 0x03, 0x18 },
52  { 0x0F, 0x02, 0x02, 0x02 }, { 0x1F, 0x02, 0x03, 0x1f },
53  { 0x3F, 0x02, 0x04, 0x00 }, { 0x0F, 0x03, 0x01, 0x1f },
54  { 0x1F, 0x03, 0x02, 0x18 }, { 0x0F, 0x03, 0x01, 0x02 },
55  { 0x1F, 0x03, 0x02, 0x1f }, { 0x3F, 0x03, 0x03, 0x00 },
56  { 0x1F, 0x04, 0x01, 0x01 }, { 0x1F, 0x04, 0x01, 0x18 },
57  { 0x3F, 0x04, 0x02, 0x00 },
58 };
59 
65 };
66 
67 #if CONFIG_SMALL
68 #define CRC_TABLE_SIZE 257
69 #else
70 #define CRC_TABLE_SIZE 1024
71 #endif
75 
76 static av_cold void mlp_init_crc(void)
77 {
78  av_crc_init(crc_63, 0, 8, 0x63, sizeof(crc_63));
79  av_crc_init(crc_1D, 0, 8, 0x1D, sizeof(crc_1D));
80  av_crc_init(crc_2D, 0, 16, 0x002D, sizeof(crc_2D));
81 }
82 
84 {
85  static AVOnce init_static_once = AV_ONCE_INIT;
86  ff_thread_once(&init_static_once, mlp_init_crc);
87 }
88 
89 uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size)
90 {
91  uint16_t crc;
92 
93  crc = av_crc(crc_2D, 0, buf, buf_size - 2);
94  crc ^= AV_RL16(buf + buf_size - 2);
95  return crc;
96 }
97 
98 uint8_t ff_mlp_checksum8(const uint8_t *buf, unsigned int buf_size)
99 {
100  uint8_t checksum = av_crc(crc_63, 0x3c, buf, buf_size - 1); // crc_63[0xa2] == 0x3c
101  checksum ^= buf[buf_size-1];
102  return checksum;
103 }
104 
105 uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size)
106 {
107  int i;
108  int num_bytes = (bit_size + 2) / 8;
109 
110  int crc = crc_1D[buf[0] & 0x3f];
111  crc = av_crc(crc_1D, crc, buf + 1, num_bytes - 2);
112  crc ^= buf[num_bytes - 1];
113 
114  for (i = 0; i < ((bit_size + 2) & 7); i++) {
115  crc <<= 1;
116  if (crc & 0x100)
117  crc ^= 0x11D;
118  crc ^= (buf[num_bytes] >> (7 - i)) & 1;
119  }
120 
121  return crc;
122 }
123 
124 uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size)
125 {
126  uint32_t scratch = 0;
127  const uint8_t *buf_end = buf + buf_size;
128 
129  for (; ((intptr_t) buf & 3) && buf < buf_end; buf++)
130  scratch ^= *buf;
131  for (; buf < buf_end - 3; buf += 4)
132  scratch ^= *((const uint32_t*)buf);
133 
134  scratch = xor_32_to_8(scratch);
135 
136  for (; buf < buf_end; buf++)
137  scratch ^= *buf;
138 
139  return scratch;
140 }
xor_32_to_8
static uint8_t xor_32_to_8(uint32_t value)
XOR four bytes into one.
Definition: mlp.h:172
AV_CHANNEL_LAYOUT_STEREO
#define AV_CHANNEL_LAYOUT_STEREO
Definition: channel_layout.h:387
AV_CHANNEL_LAYOUT_4POINT1
#define AV_CHANNEL_LAYOUT_4POINT1
Definition: channel_layout.h:393
AVCRC
uint32_t AVCRC
Definition: crc.h:46
thread.h
crc_1D
static AVCRC crc_1D[CRC_TABLE_SIZE]
Definition: mlp.c:73
ff_mlp_calculate_parity
uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size)
XOR together all the bytes of a buffer.
Definition: mlp.c:124
ff_mlp_ch_info
const ChannelInformation ff_mlp_ch_info[21]
Tables defining channel information.
Definition: mlp.c:46
crc.h
ff_mlp_checksum16
uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size)
Definition: mlp.c:89
ff_mlp_checksum8
uint8_t ff_mlp_checksum8(const uint8_t *buf, unsigned int buf_size)
MLP uses checksums that seem to be based on the standard CRC algorithm, but are not (in implementatio...
Definition: mlp.c:98
AV_CHANNEL_LAYOUT_2POINT1
#define AV_CHANNEL_LAYOUT_2POINT1
Definition: channel_layout.h:388
ChannelInformation
Definition: mlp.h:114
av_crc_init
int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size)
Initialize a CRC table.
Definition: crc.c:341
AV_CHANNEL_LAYOUT_SURROUND
#define AV_CHANNEL_LAYOUT_SURROUND
Definition: channel_layout.h:390
ff_thread_once
static int ff_thread_once(char *control, void(*routine)(void))
Definition: thread.h:205
av_cold
#define av_cold
Definition: attributes.h:90
AV_CHANNEL_LAYOUT_4POINT0
#define AV_CHANNEL_LAYOUT_4POINT0
Definition: channel_layout.h:392
intreadwrite.h
AV_CHANNEL_LAYOUT_5POINT0_BACK
#define AV_CHANNEL_LAYOUT_5POINT0_BACK
Definition: channel_layout.h:398
AV_RL16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:94
AV_ONCE_INIT
#define AV_ONCE_INIT
Definition: thread.h:203
mlp_init_crc
static av_cold void mlp_init_crc(void)
Definition: mlp.c:76
AVOnce
#define AVOnce
Definition: thread.h:202
ff_mlp_restart_checksum
uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size)
Calculate an 8-bit checksum over a restart header – a non-multiple-of-8 number of bits,...
Definition: mlp.c:105
AVChannelLayout
An AVChannelLayout holds information about the channel layout of audio data.
Definition: channel_layout.h:311
CRC_TABLE_SIZE
#define CRC_TABLE_SIZE
Definition: mlp.c:70
crc_63
static AVCRC crc_63[CRC_TABLE_SIZE]
Definition: mlp.c:72
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
AV_CHANNEL_LAYOUT_QUAD
#define AV_CHANNEL_LAYOUT_QUAD
Definition: channel_layout.h:395
AV_CHANNEL_LAYOUT_3POINT1
#define AV_CHANNEL_LAYOUT_3POINT1
Definition: channel_layout.h:391
ff_mlp_ch_layouts
const AVChannelLayout ff_mlp_ch_layouts[12]
Definition: mlp.c:60
ff_mlp_init_crc
av_cold void ff_mlp_init_crc(void)
Definition: mlp.c:83
AV_CHANNEL_LAYOUT_2_1
#define AV_CHANNEL_LAYOUT_2_1
Definition: channel_layout.h:389
channel_layout.h
crc_2D
static AVCRC crc_2D[CRC_TABLE_SIZE]
Definition: mlp.c:74
av_crc
uint32_t av_crc(const AVCRC *ctx, uint32_t crc, const uint8_t *buffer, size_t length)
Calculate the CRC of a block.
Definition: crc.c:392
mlp.h
AV_CHANNEL_LAYOUT_MONO
#define AV_CHANNEL_LAYOUT_MONO
Definition: channel_layout.h:386
ff_mlp_huffman_tables
const uint8_t ff_mlp_huffman_tables[3][18][2]
Tables defining the Huffman codes.
Definition: mlp.c:30
AV_CHANNEL_LAYOUT_5POINT1_BACK
#define AV_CHANNEL_LAYOUT_5POINT1_BACK
Definition: channel_layout.h:399