/usr/include/bitstream/mpeg/aac.h

/*****************************************************************************
 * aac.h: ISO/IEC 14496-3 Advanced Audio Coding
 *****************************************************************************
 * Copyright (C) 2010, 2013 VideoLAN
 *
 * Authors: Christophe Massiot <massiot@via.ecp.fr>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject
 * to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *****************************************************************************/

/*
 * Normative references:
 *  - ISO/IEC 14496-3 Subpart 4:1998(E)
 *    (Advanced Audio Coding, Time/Frequency Coding)
 */

#ifndef __BITSTREAM_MPEG_AAC_H__
#define __BITSTREAM_MPEG_AAC_H__

#include <stdint.h>   /* uint8_t, uint16_t, etc... */
#include <stdbool.h>  /* bool */

#ifdef __cplusplus
extern "C"
{
#endif

/*****************************************************************************
 * ADTS header
 *****************************************************************************/
#define ADTS_HEADER_SIZE        7
#define ADTS_SAMPLES_PER_BLOCK  1024

/* fixed header */
static inline void adts_set_sync(uint8_t *p_adts)
{
    p_adts[0] = 0xff;
    p_adts[1] = 0xf9; /* protection absent */
    p_adts[2] = 0x0;
    p_adts[3] = 0x0;
    p_adts[4] = 0x0;
    p_adts[5] = 0x0;
    p_adts[6] = 0x0;
}

static inline bool adts_get_protection_absent(const uint8_t *p_adts)
{
    return !!(p_adts[1] & 0x01);
}

static inline void adts_clear_protection_absent(uint8_t *p_adts)
{
    p_adts[1] &= ~0x01;
}

static inline uint8_t adts_get_profile(const uint8_t *p_adts)
{
    return p_adts[2] >> 6;
}

static inline void adts_set_profile(uint8_t *p_adts, uint8_t i_profile)
{
    p_adts[2] &= ~0xc0;
    p_adts[2] |= i_profile << 6;
}

static inline uint8_t adts_get_sampling_freq(const uint8_t *p_adts)
{
    return (p_adts[2] & 0x3c) >> 2;
}

static inline void adts_set_sampling_freq(uint8_t *p_adts, uint8_t i_freq)
{
    p_adts[2] &= ~0x3c;
    p_adts[2] |= (i_freq & 0xf) << 2;
}

static inline uint8_t adts_get_channels(const uint8_t *p_adts)
{
    return ((p_adts[2] & 0x01) << 2) | (p_adts[3] >> 6);
}

static inline void adts_set_channels(uint8_t *p_adts, uint8_t i_channels)
{
    p_adts[2] &= ~0x03; /* also clear out the private bit */
    p_adts[2] |= (i_channels & 0x7) >> 2;
    p_adts[3] &= ~0xc0;
    p_adts[3] |= (i_channels & 0x7) << 6;
}

static inline bool adts_get_copy(const uint8_t *p_adts)
{
    return !!(p_adts[3] & 0x20);
}

static inline void adts_set_copy(uint8_t *p_adts)
{
    p_adts[3] |= 0x20;
}

static inline bool adts_get_home(const uint8_t *p_adts)
{
    return !!(p_adts[3] & 0x10);
}

static inline void adts_set_home(uint8_t *p_adts)
{
    p_adts[3] |= 0x10;
}

/* variable header */
static inline void adts_get_cp_id(const uint8_t *p_adts, bool *pb_bit, bool *pb_start)
{
    *pb_bit = !!(p_adts[3] & 0x08);
    *pb_start = !!(p_adts[3] & 0x04);
}

static inline void adts_set_cp_id(uint8_t *p_adts, bool b_bit, bool b_start)
{
    p_adts[3] &= ~0x0c;
    if (b_bit)
        p_adts[3] |= 0x08;
    if (b_start)
        p_adts[3] |= 0x04;
}

static inline uint16_t adts_get_length(const uint8_t *p_adts)
{
    return ((p_adts[3] & 0x03) << 11) | (p_adts[4] << 3) | (p_adts[5] >> 5);
}

static inline void adts_set_length(uint8_t *p_adts, uint16_t i_length)
{
    p_adts[3] &= ~0x03;
    p_adts[3] |= (i_length >> 11) & 0x03;
    p_adts[4] = i_length >> 3;
    p_adts[5] &= ~0xe0;
    p_adts[5] |= (i_length << 5) & 0xe0;
}

static inline uint16_t adts_get_fullness(const uint8_t *p_adts)
{
    return ((p_adts[5] & 0x1f) << 6) | (p_adts[6] >> 2);
}

static inline void adts_set_fullness(uint8_t *p_adts, uint16_t i_fullness)
{
    p_adts[5] &= ~0x1f;
    p_adts[5] |= (i_fullness >> 6) & 0x1f;
    p_adts[6] &= ~0xfc;
    p_adts[6] |= (i_fullness << 2) & 0xfc;
}

/* blocks == number of blocks - 1 */
static inline uint8_t adts_get_num_blocks(const uint8_t *p_adts)
{
    return (p_adts[6] & 0x03);
}

static inline void adts_set_num_blocks(uint8_t *p_adts, uint8_t i_blocks_min1)
{
    p_adts[6] &= ~0x03;
    p_adts[6] |= i_blocks_min1 & 0x03;
}

static inline bool adts_sync_compare(const uint8_t *p_adts1, const uint8_t *p_adts2)
{
    return p_adts1[0] == p_adts2[0] &&
           p_adts1[1] == p_adts2[1] &&
           p_adts1[2] == p_adts2[2] &&
           (p_adts1[3] & 0xfc) == (p_adts2[3] & 0xfc);
}

/* same but only takes into account meaningful fields */
static inline bool adts_sync_compare_formats(const uint8_t *p_adts1, const uint8_t *p_adts2)
{
    return p_adts1[0] == p_adts2[0] &&
           (p_adts1[1] & 0xfe) == (p_adts2[1] & 0xfe) &&
           p_adts1[2] == p_adts2[2] &&
           (p_adts1[3] & 0xc0) == (p_adts2[3] & 0xc0);
}

#ifdef __cplusplus
}
#endif

#endif
libbitstream-dev 1.1-1 / usr / include / bitstream / mpeg / aac.h
