FFmpeg
Macros | Functions | Variables
mlp.c File Reference
#include <stdint.h>
#include "libavutil/crc.h"
#include "libavutil/intreadwrite.h"
#include "mlp.h"

Go to the source code of this file.

Macros

#define CRC_TABLE_SIZE   1024
 

Functions

av_cold void ff_mlp_init_crc (void)
 
uint16_t ff_mlp_checksum16 (const uint8_t *buf, unsigned int buf_size)
 
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 implementation terms, the table lookup and XOR are reversed). More...
 
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, starting two bits into the first byte of buf. More...
 
uint8_t ff_mlp_calculate_parity (const uint8_t *buf, unsigned int buf_size)
 XOR together all the bytes of a buffer. More...
 

Variables

const uint8_t ff_mlp_huffman_tables [3][18][2]
 Tables defining the Huffman codes. More...
 
const ChannelInformation ff_mlp_ch_info [21]
 Tables defining channel information. More...
 
const uint64_t ff_mlp_channel_layouts [12]
 
static int crc_init = 0
 
static AVCRC crc_63 [CRC_TABLE_SIZE]
 
static AVCRC crc_1D [CRC_TABLE_SIZE]
 
static AVCRC crc_2D [CRC_TABLE_SIZE]
 

Macro Definition Documentation

#define CRC_TABLE_SIZE   1024

Definition at line 69 of file mlp.c.

Function Documentation

av_cold void ff_mlp_init_crc ( void  )

Definition at line 75 of file mlp.c.

Referenced by init_static(), mlp_encode_init(), and mlp_init().

uint16_t ff_mlp_checksum16 ( const uint8_t buf,
unsigned int  buf_size 
)

Definition at line 85 of file mlp.c.

Referenced by ff_mlp_read_major_sync(), truehd_core_filter(), and write_major_sync().

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 implementation terms, the table lookup and XOR are reversed).

We can implement this behavior using a standard av_crc on all but the last element, then XOR that with the last element.

Definition at line 94 of file mlp.c.

Referenced by read_access_unit(), and write_substrs().

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, starting two bits into the first byte of buf.

Definition at line 101 of file mlp.c.

Referenced by read_restart_header(), and write_restart_header().

uint8_t ff_mlp_calculate_parity ( const uint8_t buf,
unsigned int  buf_size 
)

XOR together all the bytes of a buffer.

Does this belong in dspcontext?

Definition at line 120 of file mlp.c.

Referenced by read_access_unit(), and write_substrs().

Variable Documentation

const uint8_t ff_mlp_huffman_tables[3][18][2]
Initial value:
= {
{
{0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
{0x04, 3}, {0x05, 3}, {0x06, 3}, {0x07, 3},
{0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
}, {
{0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
{0x02, 2}, {0x03, 2},
{0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
}, {
{0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3},
{0x01, 1},
{0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9},
}
}

Tables defining the Huffman codes.

There are three entropy coding methods used in MLP (four if you count "none" as a method). These use the same sequences for codes starting with 00 or 01, but have different codes starting with 1.

Definition at line 28 of file mlp.c.

Referenced by codebook_bits_offset(), init_static(), and write_block_data().

const ChannelInformation ff_mlp_ch_info[21]
Initial value:
= {
{ 0x01, 0x01, 0x00, 0x1f }, { 0x03, 0x02, 0x00, 0x1b },
{ 0x07, 0x02, 0x01, 0x1f }, { 0x0F, 0x02, 0x02, 0x19 },
{ 0x07, 0x02, 0x01, 0x03 }, { 0x0F, 0x02, 0x02, 0x1f },
{ 0x1F, 0x02, 0x03, 0x01 }, { 0x07, 0x02, 0x01, 0x1a },
{ 0x0F, 0x02, 0x02, 0x1f }, { 0x1F, 0x02, 0x03, 0x18 },
{ 0x0F, 0x02, 0x02, 0x02 }, { 0x1F, 0x02, 0x03, 0x1f },
{ 0x3F, 0x02, 0x04, 0x00 }, { 0x0F, 0x03, 0x01, 0x1f },
{ 0x1F, 0x03, 0x02, 0x18 }, { 0x0F, 0x03, 0x01, 0x02 },
{ 0x1F, 0x03, 0x02, 0x1f }, { 0x3F, 0x03, 0x03, 0x00 },
{ 0x1F, 0x04, 0x01, 0x01 }, { 0x1F, 0x04, 0x01, 0x18 },
{ 0x3F, 0x04, 0x02, 0x00 },
}

Tables defining channel information.

Possible channel arrangements are:

(Group 1) C (Group 1) L, R (Group 1) Lf, Rf / (Group 2) S (Group 1) Lf, Rf / (Group 2) Ls, Rs (Group 1) Lf, Rf / (Group 2) LFE (Group 1) Lf, Rf / (Group 2) LFE, S (Group 1) Lf, Rf / (Group 2) LFE, Ls, Rs (Group 1) Lf, Rf / (Group 2) C (Group 1) Lf, Rf / (Group 2) C, S (Group 1) Lf, Rf / (Group 2) C, Ls, Rs (Group 1) Lf, Rf / (Group 2) C, LFE (Group 1) Lf, Rf / (Group 2) C, LFE, S (Group 1) Lf, Rf / (Group 2) C, LFE, Ls, Rs (Group 1) Lf, Rf C / (Group 2) S (Group 1) Lf, Rf C / (Group 2) Ls, Rs (Group 1) Lf, Rf C / (Group 2) LFE (Group 1) Lf, Rf C / (Group 2) LFE, S (Group 1) Lf, Rf C / (Group 2) LFE, Ls, Rs (Group 1) Lf, Rf Ls Rs / (Group 2) LFE (Group 1) Lf, Rf Ls Rs / (Group 2) C (Group 1) Lf, Rf, Ls, Rs / (Group 2) C, LFE

Definition at line 44 of file mlp.c.

Referenced by mlp_encode_init().

const uint64_t ff_mlp_channel_layouts[12]
Initial value:
= {
}
#define AV_CH_LAYOUT_4POINT1
#define AV_CH_LAYOUT_SURROUND
#define AV_CH_LAYOUT_4POINT0
#define AV_CH_LAYOUT_STEREO
#define AV_CH_LAYOUT_QUAD
#define AV_CH_LAYOUT_2_1
#define AV_CH_LAYOUT_3POINT1
#define AV_CH_LAYOUT_5POINT1_BACK
#define AV_CH_LAYOUT_5POINT0_BACK
#define AV_CH_LAYOUT_2POINT1
#define AV_CH_LAYOUT_MONO

Definition at line 58 of file mlp.c.

Referenced by mlp_encode_close().

int crc_init = 0
static

Definition at line 65 of file mlp.c.

Referenced by ff_mlp_init_crc().

AVCRC crc_63[CRC_TABLE_SIZE]
static

Definition at line 71 of file mlp.c.

Referenced by ff_mlp_checksum8(), and ff_mlp_init_crc().

AVCRC crc_1D[CRC_TABLE_SIZE]
static

Definition at line 72 of file mlp.c.

Referenced by ff_mlp_init_crc(), and ff_mlp_restart_checksum().

AVCRC crc_2D[CRC_TABLE_SIZE]
static

Definition at line 73 of file mlp.c.

Referenced by ff_mlp_checksum16(), and ff_mlp_init_crc().