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252 lines
6.7 KiB
252 lines
6.7 KiB
/*****************************************************************************
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* mpga.h: ISO/IEC 11172-3 and 13818-3 MPEG audio
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*****************************************************************************
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* Copyright (C) 2013 VideoLAN
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*
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* Authors: Christophe Massiot <massiot@via.ecp.fr>
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject
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* to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*****************************************************************************/
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/*
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* Normative references:
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* - ISO/IEC 11172-3
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* - ISO/IEC 13818-3
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*/
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#ifndef __BITSTREAM_MPEG_MPGA_H__
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#define __BITSTREAM_MPEG_MPGA_H__
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#include <stdint.h> /* uint8_t, uint16_t, etc... */
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#include <stdbool.h> /* bool */
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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/*****************************************************************************
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* MPEG audio header
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*****************************************************************************/
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#define MPGA_HEADER_SIZE 4
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#define MPGA_ID_1 1
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#define MPGA_ID_2 0
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#define MPGA_LAYER_1 3
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#define MPGA_LAYER_2 2
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#define MPGA_LAYER_3 1
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#define MPGA_LAYER_ADTS 0
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#define MPGA_BITRATE_INVALID 15
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#define MPGA_SAMPLERATE_INVALID 3
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#define MPGA_MODE_STEREO 0
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#define MPGA_MODE_JOINT 1
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#define MPGA_MODE_DUAL_MONO 2
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#define MPGA_MODE_MONO 3
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#define MPGA_EMPHASIS_NONE 0
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#define MPGA_EMPHASIS_50_15 1
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#define MPGA_EMPHASIS_INVALID 2
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#define MPGA_EMPHASIS_J_17 3
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static inline void mpga_set_sync(uint8_t *p_mpga)
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{
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p_mpga[0] = 0xff;
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p_mpga[1] = 0xf9;
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p_mpga[2] = 0x0;
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p_mpga[3] = 0x0;
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}
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/* unofficial extension */
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static inline bool mpga_get_mpeg25(const uint8_t *p_mpga)
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{
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return !(p_mpga[1] & 0x10);
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}
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static inline void mpga_set_mpeg25(uint8_t *p_mpga)
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{
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p_mpga[1] &= ~0x10;
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}
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static inline bool mpga_get_id(const uint8_t *p_mpga)
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{
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return !!(p_mpga[1] & 0x08);
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}
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static inline void mpga_clear_id(uint8_t *p_mpga)
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{
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p_mpga[1] &= ~0x08;
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}
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static inline uint8_t mpga_get_layer(const uint8_t *p_mpga)
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{
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return (p_mpga[1] & 0x06) >> 1;
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}
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static inline void mpga_set_layer(uint8_t *p_mpga, uint8_t i_layer)
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{
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p_mpga[1] &= ~0x06;
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p_mpga[1] |= (i_layer & 0x3) << 1;
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}
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static inline bool mpga_get_protection_absent(const uint8_t *p_mpga)
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{
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return !!(p_mpga[1] & 0x01);
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}
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static inline void mpga_clear_protection_absent(uint8_t *p_mpga)
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{
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p_mpga[1] &= ~0x01;
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}
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static inline uint8_t mpga_get_bitrate_index(const uint8_t *p_mpga)
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{
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return p_mpga[2] >> 4;
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}
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static inline void mpga_set_bitrate_index(uint8_t *p_mpga, uint8_t i_index)
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{
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p_mpga[2] &= ~0xf0;
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p_mpga[2] |= i_index << 4;
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}
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static inline uint8_t mpga_get_sampling_freq(const uint8_t *p_mpga)
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{
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return (p_mpga[2] & 0xc) >> 2;
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}
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static inline void mpga_set_sampling_freq(uint8_t *p_mpga, uint8_t i_freq)
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{
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p_mpga[2] &= ~0x0c;
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p_mpga[2] |= (i_freq & 0x3) << 2;
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}
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static inline bool mpga_get_padding(const uint8_t *p_mpga)
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{
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return !!(p_mpga[2] & 0x02);
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}
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static inline void mpga_set_padding(uint8_t *p_mpga)
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{
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p_mpga[2] |= 0x02;
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}
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static inline uint8_t mpga_get_mode(const uint8_t *p_mpga)
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{
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return (p_mpga[3] & 0xc0) >> 6;
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}
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static inline void mpga_set_mode(uint8_t *p_mpga, uint8_t i_mode)
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{
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p_mpga[3] &= ~0xc0;
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p_mpga[3] |= i_mode << 6;
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}
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static inline uint8_t mpga_get_mode_ext(const uint8_t *p_mpga)
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{
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return (p_mpga[3] & 0x30) >> 4;
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}
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static inline void mpga_set_mode_ext(uint8_t *p_mpga, uint8_t i_mode_ext)
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{
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p_mpga[3] &= ~0x30;
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p_mpga[3] |= (i_mode_ext & 0x3) << 4;
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}
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static inline bool mpga_get_copyright(const uint8_t *p_mpga)
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{
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return !!(p_mpga[3] & 0x80);
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}
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static inline void mpga_set_copyright(uint8_t *p_mpga)
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{
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p_mpga[3] |= 0x80;
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}
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static inline bool mpga_get_original(const uint8_t *p_mpga)
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{
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return !!(p_mpga[3] & 0x40);
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}
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static inline void mpga_set_original(uint8_t *p_mpga)
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{
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p_mpga[3] |= 0x40;
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}
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static inline uint8_t mpga_get_emphasis(const uint8_t *p_mpga)
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{
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return p_mpga[3] & 0x03;
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}
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static inline void mpga_set_emphasis(uint8_t *p_mpga, uint8_t i_emphasis)
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{
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p_mpga[3] &= ~0x03;
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p_mpga[3] |= i_emphasis & 0x03;
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}
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static inline bool mpga_sync_compare(const uint8_t *p_mpga1, const uint8_t *p_mpga2)
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{
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return p_mpga1[0] == p_mpga2[0] &&
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p_mpga1[1] == p_mpga2[1] &&
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(p_mpga1[2] & 0xfc) == (p_mpga2[2] & 0xfc) &&
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p_mpga1[3] == p_mpga2[3];
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}
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/* same but only takes into account meaningful fields */
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static inline bool mpga_sync_compare_formats(const uint8_t *p_mpga1, const uint8_t *p_mpga2)
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{
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if (!(p_mpga1[0] == p_mpga2[0] &&
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(p_mpga1[1] & 0xfe) == (p_mpga2[1] & 0xfe) &&
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(p_mpga1[2] & 0xfc) == (p_mpga2[2] & 0xfc)))
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return false;
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/* consider stereo and joint stereo the same - because encoders can
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* switch on the fly */
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uint8_t i_mode1 = mpga_get_mode(p_mpga1);
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uint8_t i_mode2 = mpga_get_mode(p_mpga2);
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if (i_mode1 == MPGA_MODE_JOINT) i_mode1 = MPGA_MODE_STEREO;
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if (i_mode2 == MPGA_MODE_JOINT) i_mode2 = MPGA_MODE_STEREO;
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return i_mode1 == i_mode2;
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}
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/* same but without comparing bitrate (free bitrate) */
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static inline bool mpga_sync_compare_formats_free(const uint8_t *p_mpga1, const uint8_t *p_mpga2)
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{
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if (!(p_mpga1[0] == p_mpga2[0] &&
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(p_mpga1[1] & 0xfe) == (p_mpga2[1] & 0xfe) &&
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(p_mpga1[2] & 0xc) == (p_mpga2[2] & 0xc)))
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return false;
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/* consider stereo and joint stereo the same - because encoders can
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* switch on the fly */
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uint8_t i_mode1 = mpga_get_mode(p_mpga1);
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uint8_t i_mode2 = mpga_get_mode(p_mpga2);
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if (i_mode1 == MPGA_MODE_JOINT) i_mode1 = MPGA_MODE_STEREO;
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if (i_mode2 == MPGA_MODE_JOINT) i_mode2 = MPGA_MODE_STEREO;
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return i_mode1 == i_mode2;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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