FFmpeg/libavcodec/mlp.h
Reimar Döffinger a55247e761 Specify maximum sample rate of MLP by defining the factor relative to 48000
instead of directly.
This makes clear that the code assumes the maximum sample rate to be
a multiple of 48000 and also removes the division from the MAX_BLOCKSIZE
macros, which causes an issue with the Solaris assembler where "/" is
a comment marker unless the --divide option is used.

Originally committed as revision 20026 to svn://svn.ffmpeg.org/ffmpeg/trunk
2009-09-26 16:04:35 +00:00

128 lines
4.3 KiB
C

/*
* MLP codec common header file
* Copyright (c) 2007-2008 Ian Caulfield
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_MLP_H
#define AVCODEC_MLP_H
#include <stdint.h>
#include "avcodec.h"
/** Last possible matrix channel for each codec */
#define MAX_MATRIX_CHANNEL_MLP 5
#define MAX_MATRIX_CHANNEL_TRUEHD 7
/** Maximum number of channels in a valid stream.
* MLP : 5.1 + 2 noise channels -> 8 channels
* TrueHD: 7.1 -> 8 channels
*/
#define MAX_CHANNELS 8
/** Maximum number of matrices used in decoding; most streams have one matrix
* per output channel, but some rematrix a channel (usually 0) more than once.
*/
#define MAX_MATRICES_MLP 6
#define MAX_MATRICES_TRUEHD 8
#define MAX_MATRICES 8
/** Maximum number of substreams that can be decoded.
* MLP's limit is 2. TrueHD supports at least up to 3.
*/
#define MAX_SUBSTREAMS 3
/** which multiple of 48000 the maximum sample rate is */
#define MAX_RATEFACTOR 4
/** maximum sample frequency seen in files */
#define MAX_SAMPLERATE (MAX_RATEFACTOR * 48000)
/** maximum number of audio samples within one access unit */
#define MAX_BLOCKSIZE (40 * MAX_RATEFACTOR)
/** next power of two greater than MAX_BLOCKSIZE */
#define MAX_BLOCKSIZE_POW2 (64 * MAX_RATEFACTOR)
/** number of allowed filters */
#define NUM_FILTERS 2
/** The maximum number of taps in IIR and FIR filters. */
#define MAX_FIR_ORDER 8
#define MAX_IIR_ORDER 4
/** Code that signals end of a stream. */
#define END_OF_STREAM 0xd234d234
#define FIR 0
#define IIR 1
/** filter data */
typedef struct {
uint8_t order; ///< number of taps in filter
uint8_t shift; ///< Right shift to apply to output of filter.
int32_t state[MAX_FIR_ORDER];
} FilterParams;
/** sample data coding information */
typedef struct {
FilterParams filter_params[NUM_FILTERS];
int32_t coeff[NUM_FILTERS][MAX_FIR_ORDER];
int16_t huff_offset; ///< Offset to apply to residual values.
int32_t sign_huff_offset; ///< sign/rounding-corrected version of huff_offset
uint8_t codebook; ///< Which VLC codebook to use to read residuals.
uint8_t huff_lsbs; ///< Size of residual suffix not encoded using VLC.
} ChannelParams;
/** 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.
*/
extern const uint8_t ff_mlp_huffman_tables[3][18][2];
/** 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.
*/
uint8_t ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size);
uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_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.
*/
uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size);
/** XOR together all the bytes of a buffer.
* Does this belong in dspcontext?
*/
uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size);
void ff_mlp_init_crc(void);
/** XOR four bytes into one. */
static inline uint8_t xor_32_to_8(uint32_t value)
{
value ^= value >> 16;
value ^= value >> 8;
return value;
}
#endif /* AVCODEC_MLP_H */