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/*
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mpeghead.h - compact version of famous library mpg123
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Copyright (C) 2017 Uncle Mike
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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*/
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#ifndef MPEGHEAD_H
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#define MPEGHEAD_H
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#define HDR_SYNC 0xffe00000
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#define HDR_SYNC_VAL(h) (((h) & HDR_SYNC) >> 21)
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#define HDR_VERSION 0x00180000
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#define HDR_VERSION_VAL(h) (((h) & HDR_VERSION) >> 19)
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#define HDR_LAYER 0x00060000
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#define HDR_LAYER_VAL(h) (((h) & HDR_LAYER) >> 17)
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#define HDR_CRC 0x00010000
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#define HDR_CRC_VAL(h) (((h) & HDR_CRC) >> 16)
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#define HDR_BITRATE 0x0000f000
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#define HDR_BITRATE_VAL(h) (((h) & HDR_BITRATE) >> 12)
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#define HDR_SAMPLERATE 0x00000c00
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#define HDR_SAMPLERATE_VAL(h) (((h) & HDR_SAMPLERATE) >> 10)
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#define HDR_PADDING 0x00000200
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#define HDR_PADDING_VAL(h) (((h) & HDR_PADDING) >> 9)
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#define HDR_PRIVATE 0x00000100
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#define HDR_PRIVATE_VAL(h) (((h) & HDR_PRIVATE) >> 8)
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#define HDR_CHANNEL 0x000000c0
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#define HDR_CHANNEL_VAL(h) (((h) & HDR_CHANNEL) >> 6)
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#define HDR_CHANEX 0x00000030
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#define HDR_CHANEX_VAL(h) (((h) & HDR_CHANEX) >> 4)
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#define HDR_COPYRIGHT 0x00000008
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#define HDR_COPYRIGHT_VAL(h) (((h) & HDR_COPYRIGHT) >> 3)
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#define HDR_ORIGINAL 0x00000004
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#define HDR_ORIGINAL_VAL(h) (((h) & HDR_ORIGINAL) >> 2)
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#define HDR_EMPHASIS 0x00000003
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#define HDR_EMPHASIS_VAL(h) (((h) & HDR_EMPHASIS) >> 0)
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// a generic mask for telling if a header is somewhat valid for the current stream.
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// meaning: Most basic info is not allowed to change.
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// checking of channel count needs to be done, too, though. So,
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// if channel count matches, frames are decoded the same way: frame buffers and decoding
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// routines can stay the same, especially frame buffers (think spf * channels!).
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#define HDR_CMPMASK (HDR_SYNC|HDR_VERSION|HDR_LAYER|HDR_SAMPLERATE)
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// A stricter mask, for matching free format headers.
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#define HDR_SAMEMASK (HDR_SYNC|HDR_VERSION|HDR_LAYER|HDR_BITRATE|HDR_SAMPLERATE|HDR_CHANNEL|HDR_CHANEX)
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// free format headers have zero bitrate value.
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#define HDR_FREE_FORMAT(head) (!(head & HDR_BITRATE))
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// a mask for changed sampling rate (version or rate bits).
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#define HDR_SAMPMASK (HDR_VERSION|HDR_SAMPLERATE)
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#endif//MPEGHEAD_H
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