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 
24 #include "libavutil/crc.h"
25 #include "libavutil/intreadwrite.h"
26 #include "libavutil/thread.h"
27 #include "mlp.h"
28 
29 const uint8_t ff_mlp_huffman_tables[3][18][2] = {
30  { /* Huffman table 0, -7 - +10 */
31  {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
32  {0x04, 3}, {0x05, 3}, {0x06, 3}, {0x07, 3},
33  {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
34  }, { /* Huffman table 1, -7 - +8 */
35  {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
36  {0x02, 2}, {0x03, 2},
37  {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
38  }, { /* Huffman table 2, -7 - +7 */
39  {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
40  {0x01, 1},
41  {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
42  }
43 };
44 
46  { 0x01, 0x01, 0x00, 0x1f }, { 0x03, 0x02, 0x00, 0x1b },
47  { 0x07, 0x02, 0x01, 0x1f }, { 0x0F, 0x02, 0x02, 0x19 },
48  { 0x07, 0x02, 0x01, 0x03 }, { 0x0F, 0x02, 0x02, 0x1f },
49  { 0x1F, 0x02, 0x03, 0x01 }, { 0x07, 0x02, 0x01, 0x1a },
50  { 0x0F, 0x02, 0x02, 0x1f }, { 0x1F, 0x02, 0x03, 0x18 },
51  { 0x0F, 0x02, 0x02, 0x02 }, { 0x1F, 0x02, 0x03, 0x1f },
52  { 0x3F, 0x02, 0x04, 0x00 }, { 0x0F, 0x03, 0x01, 0x1f },
53  { 0x1F, 0x03, 0x02, 0x18 }, { 0x0F, 0x03, 0x01, 0x02 },
54  { 0x1F, 0x03, 0x02, 0x1f }, { 0x3F, 0x03, 0x03, 0x00 },
55  { 0x1F, 0x04, 0x01, 0x01 }, { 0x1F, 0x04, 0x01, 0x18 },
56  { 0x3F, 0x04, 0x02, 0x00 },
57 };
58 
59 const uint64_t ff_mlp_channel_layouts[12] = {
64 };
65 
66 #if CONFIG_SMALL
67 #define CRC_TABLE_SIZE 257
68 #else
69 #define CRC_TABLE_SIZE 1024
70 #endif
74 
75 static av_cold void mlp_init_crc(void)
76 {
77  av_crc_init(crc_63, 0, 8, 0x63, sizeof(crc_63));
78  av_crc_init(crc_1D, 0, 8, 0x1D, sizeof(crc_1D));
79  av_crc_init(crc_2D, 0, 16, 0x002D, sizeof(crc_2D));
80 }
81 
83 {
84  static AVOnce init_static_once = AV_ONCE_INIT;
85  ff_thread_once(&init_static_once, mlp_init_crc);
86 }
87 
88 uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size)
89 {
90  uint16_t crc;
91 
92  crc = av_crc(crc_2D, 0, buf, buf_size - 2);
93  crc ^= AV_RL16(buf + buf_size - 2);
94  return crc;
95 }
96 
97 uint8_t ff_mlp_checksum8(const uint8_t *buf, unsigned int buf_size)
98 {
99  uint8_t checksum = av_crc(crc_63, 0x3c, buf, buf_size - 1); // crc_63[0xa2] == 0x3c
100  checksum ^= buf[buf_size-1];
101  return checksum;
102 }
103 
104 uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size)
105 {
106  int i;
107  int num_bytes = (bit_size + 2) / 8;
108 
109  int crc = crc_1D[buf[0] & 0x3f];
110  crc = av_crc(crc_1D, crc, buf + 1, num_bytes - 2);
111  crc ^= buf[num_bytes - 1];
112 
113  for (i = 0; i < ((bit_size + 2) & 7); i++) {
114  crc <<= 1;
115  if (crc & 0x100)
116  crc ^= 0x11D;
117  crc ^= (buf[num_bytes] >> (7 - i)) & 1;
118  }
119 
120  return crc;
121 }
122 
123 uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size)
124 {
125  uint32_t scratch = 0;
126  const uint8_t *buf_end = buf + buf_size;
127 
128  for (; ((intptr_t) buf & 3) && buf < buf_end; buf++)
129  scratch ^= *buf;
130  for (; buf < buf_end - 3; buf += 4)
131  scratch ^= *((const uint32_t*)buf);
132 
133  scratch = xor_32_to_8(scratch);
134 
135  for (; buf < buf_end; buf++)
136  scratch ^= *buf;
137 
138  return scratch;
139 }
AV_CH_LAYOUT_5POINT0_BACK
#define AV_CH_LAYOUT_5POINT0_BACK
Definition: channel_layout.h:102
xor_32_to_8
static uint8_t xor_32_to_8(uint32_t value)
XOR four bytes into one.
Definition: mlp.h:160
AVCRC
uint32_t AVCRC
Definition: crc.h:47
thread.h
AV_CH_LAYOUT_MONO
#define AV_CH_LAYOUT_MONO
Definition: channel_layout.h:90
crc_1D
static AVCRC crc_1D[CRC_TABLE_SIZE]
Definition: mlp.c:72
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:123
ff_mlp_ch_info
const ChannelInformation ff_mlp_ch_info[21]
Tables defining channel information.
Definition: mlp.c:45
crc.h
ff_mlp_checksum16
uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size)
Definition: mlp.c:88
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:97
ChannelInformation
Definition: mlp.h:102
AV_CH_LAYOUT_STEREO
#define AV_CH_LAYOUT_STEREO
Definition: channel_layout.h:91
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_CH_LAYOUT_QUAD
#define AV_CH_LAYOUT_QUAD
Definition: channel_layout.h:99
ff_thread_once
static int ff_thread_once(char *control, void(*routine)(void))
Definition: thread.h:175
av_cold
#define av_cold
Definition: attributes.h:90
intreadwrite.h
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
ff_mlp_channel_layouts
const uint64_t ff_mlp_channel_layouts[12]
Definition: mlp.c:59
AV_CH_LAYOUT_2_1
#define AV_CH_LAYOUT_2_1
Definition: channel_layout.h:93
AV_ONCE_INIT
#define AV_ONCE_INIT
Definition: thread.h:173
mlp_init_crc
static av_cold void mlp_init_crc(void)
Definition: mlp.c:75
AVOnce
#define AVOnce
Definition: thread.h:172
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:104
CRC_TABLE_SIZE
#define CRC_TABLE_SIZE
Definition: mlp.c:69
AV_CH_LAYOUT_5POINT1_BACK
#define AV_CH_LAYOUT_5POINT1_BACK
Definition: channel_layout.h:103
crc_63
static AVCRC crc_63[CRC_TABLE_SIZE]
Definition: mlp.c:71
AV_CH_LAYOUT_3POINT1
#define AV_CH_LAYOUT_3POINT1
Definition: channel_layout.h:95
i
int i
Definition: input.c:407
AV_CH_LAYOUT_2POINT1
#define AV_CH_LAYOUT_2POINT1
Definition: channel_layout.h:92
AV_CH_LAYOUT_4POINT1
#define AV_CH_LAYOUT_4POINT1
Definition: channel_layout.h:97
ff_mlp_init_crc
av_cold void ff_mlp_init_crc(void)
Definition: mlp.c:82
AV_CH_LAYOUT_SURROUND
#define AV_CH_LAYOUT_SURROUND
Definition: channel_layout.h:94
checksum
static volatile int checksum
Definition: adler32.c:30
crc_2D
static AVCRC crc_2D[CRC_TABLE_SIZE]
Definition: mlp.c:73
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
ff_mlp_huffman_tables
const uint8_t ff_mlp_huffman_tables[3][18][2]
Tables defining the Huffman codes.
Definition: mlp.c:29
AV_CH_LAYOUT_4POINT0
#define AV_CH_LAYOUT_4POINT0
Definition: channel_layout.h:96