libavcodec/adpcm_data.c File Reference

ADPCM tables. More...

#include <stdint.h>

Go to the source code of this file.

Variables
const int8_t	ff_adpcm_index_table [16]
const int16_t	ff_adpcm_step_table [89]
	This is the step table.
const int16_t	ff_adpcm_AdaptationTable []
const uint8_t	ff_adpcm_AdaptCoeff1 []
	Divided by 4 to fit in 8-bit integers.
const int8_t	ff_adpcm_AdaptCoeff2 []
	Divided by 4 to fit in 8-bit integers.
const int16_t	ff_adpcm_yamaha_indexscale []
const int8_t	ff_adpcm_yamaha_difflookup []

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Detailed Description

ADPCM tables.

Definition in file adpcm_data.c.

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Variable Documentation

const int16_t ff_adpcm_AdaptationTable[]

Initial value:

 {
    230, 230, 230, 230, 307, 409, 512, 614,
    768, 614, 512, 409, 307, 230, 230, 230
}

Definition at line 55 of file adpcm_data.c.

Referenced by adpcm_compress_trellis(), adpcm_ct_expand_nibble(), adpcm_ms_compress_sample(), and adpcm_ms_expand_nibble().

const uint8_t ff_adpcm_AdaptCoeff1[]

Initial value:

 {
    64, 128, 0, 48, 60, 115, 98
}

Divided by 4 to fit in 8-bit integers.

Definition at line 61 of file adpcm_data.c.

Referenced by adpcm_decode_frame(), and adpcm_encode_init().

const int8_t ff_adpcm_AdaptCoeff2[]

Initial value:

 {
    0, -64, 0, 16, 0, -52, -58
}

Divided by 4 to fit in 8-bit integers.

Definition at line 66 of file adpcm_data.c.

Referenced by adpcm_decode_frame(), and adpcm_encode_init().

const int8_t ff_adpcm_index_table[16]

Initial value:

 {
    -1, -1, -1, -1, 2, 4, 6, 8,
    -1, -1, -1, -1, 2, 4, 6, 8,
}

Definition at line 31 of file adpcm_data.c.

Referenced by adpcm_compress_trellis(), adpcm_ima_compress_sample(), adpcm_ima_expand_nibble(), adpcm_ima_qt_compress_sample(), and adpcm_ima_qt_expand_nibble().

const int16_t ff_adpcm_step_table[89]

Initial value:

 {
        7,     8,     9,    10,    11,    12,    13,    14,    16,    17,
       19,    21,    23,    25,    28,    31,    34,    37,    41,    45,
       50,    55,    60,    66,    73,    80,    88,    97,   107,   118,
      130,   143,   157,   173,   190,   209,   230,   253,   279,   307,
      337,   371,   408,   449,   494,   544,   598,   658,   724,   796,
      876,   963,  1060,  1166,  1282,  1411,  1552,  1707,  1878,  2066,
     2272,  2499,  2749,  3024,  3327,  3660,  4026,  4428,  4871,  5358,
     5894,  6484,  7132,  7845,  8630,  9493, 10442, 11487, 12635, 13899,
    15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
}

This is the step table.

Note that many programs use slight deviations from this table, but such deviations are negligible:

Definition at line 40 of file adpcm_data.c.

Referenced by adpcm_compress_trellis(), adpcm_decode_frame(), adpcm_ima_compress_sample(), adpcm_ima_expand_nibble(), adpcm_ima_qt_compress_sample(), and adpcm_ima_qt_expand_nibble().

const int8_t ff_adpcm_yamaha_difflookup[]

Initial value:

 {
     1,  3,  5,  7,  9,  11,  13,  15,
    -1, -3, -5, -7, -9, -11, -13, -15
}

Definition at line 75 of file adpcm_data.c.

Referenced by adpcm_ima_compress_sample(), adpcm_yamaha_compress_sample(), and adpcm_yamaha_expand_nibble().

const int16_t ff_adpcm_yamaha_indexscale[]

Initial value:

 {
    230, 230, 230, 230, 307, 409, 512, 614,
    230, 230, 230, 230, 307, 409, 512, 614
}

Definition at line 70 of file adpcm_data.c.

Referenced by adpcm_compress_trellis(), adpcm_yamaha_compress_sample(), and adpcm_yamaha_expand_nibble().