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| Rev | Author | Line No. | Line |
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| 1 | pmbaty | 1 | /* |
| 2 | libmpg123: MPEG Audio Decoder library |
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| 3 | |||
| 4 | separate header just for audio format definitions not tied to |
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| 5 | library code |
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| 6 | |||
| 7 | copyright 1995-2015 by the mpg123 project |
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| 8 | free software under the terms of the LGPL 2.1 |
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| 9 | see COPYING and AUTHORS files in distribution or http://mpg123.org |
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| 10 | */ |
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| 11 | |||
| 12 | #ifndef MPG123_ENC_H |
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| 13 | #define MPG123_ENC_H |
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| 14 | |||
| 15 | /** \file fmt123.h Audio format definitions. */ |
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| 16 | |||
| 17 | /** \defgroup mpg123_enc mpg123 PCM sample encodings |
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| 18 | * These are definitions for audio formats used by libmpg123 and |
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| 19 | * libout123. |
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| 20 | * |
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| 21 | * @{ |
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| 22 | */ |
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| 23 | |||
| 24 | /** An enum over all sample types possibly known to mpg123. |
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| 25 | * The values are designed as bit flags to allow bitmasking for encoding |
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| 26 | * families. |
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| 27 | * This is also why the enum is not used as type for actual encoding variables, |
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| 28 | * plain integers (at least 16 bit, 15 bit being used) cover the possible |
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| 29 | * combinations of these flags. |
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| 30 | * |
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| 31 | * Note that (your build of) libmpg123 does not necessarily support all these. |
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| 32 | * Usually, you can expect the 8bit encodings and signed 16 bit. |
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| 33 | * Also 32bit float will be usual beginning with mpg123-1.7.0 . |
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| 34 | * What you should bear in mind is that (SSE, etc) optimized routines may be |
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| 35 | * absent for some formats. We do have SSE for 16, 32 bit and float, though. |
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| 36 | * 24 bit integer is done via postprocessing of 32 bit output -- just cutting |
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| 37 | * the last byte, no rounding, even. If you want better, do it yourself. |
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| 38 | * |
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| 39 | * All formats are in native byte order. If you need different endinaness, you |
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| 40 | * can simply postprocess the output buffers (libmpg123 wouldn't do anything |
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| 41 | * else). The macro MPG123_SAMPLESIZE() can be helpful there. |
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| 42 | */ |
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| 43 | enum mpg123_enc_enum |
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| 44 | { |
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| 45 | /* 0000 0000 0000 1111 Some 8 bit integer encoding. */ |
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| 46 | MPG123_ENC_8 = 0x00f |
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| 47 | /* 0000 0000 0100 0000 Some 16 bit integer encoding. */ |
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| 48 | , MPG123_ENC_16 = 0x040 |
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| 49 | /* 0100 0000 0000 0000 Some 24 bit integer encoding. */ |
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| 50 | , MPG123_ENC_24 = 0x4000 |
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| 51 | /* 0000 0001 0000 0000 Some 32 bit integer encoding. */ |
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| 52 | , MPG123_ENC_32 = 0x100 |
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| 53 | /* 0000 0000 1000 0000 Some signed integer encoding. */ |
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| 54 | , MPG123_ENC_SIGNED = 0x080 |
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| 55 | /* 0000 1110 0000 0000 Some float encoding. */ |
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| 56 | , MPG123_ENC_FLOAT = 0xe00 |
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| 57 | /* 0000 0000 1101 0000 signed 16 bit */ |
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| 58 | , MPG123_ENC_SIGNED_16 = (MPG123_ENC_16|MPG123_ENC_SIGNED|0x10) |
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| 59 | /* 0000 0000 0110 0000 unsigned 16 bit */ |
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| 60 | , MPG123_ENC_UNSIGNED_16 = (MPG123_ENC_16|0x20) |
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| 61 | /* 0000 0000 0000 0001 unsigned 8 bit */ |
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| 62 | , MPG123_ENC_UNSIGNED_8 = 0x01 |
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| 63 | /* 0000 0000 1000 0010 signed 8 bit */ |
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| 64 | , MPG123_ENC_SIGNED_8 = (MPG123_ENC_SIGNED|0x02) |
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| 65 | /* 0000 0000 0000 0100 ulaw 8 bit */ |
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| 66 | , MPG123_ENC_ULAW_8 = 0x04 |
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| 67 | /* 0000 0000 0000 1000 alaw 8 bit */ |
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| 68 | , MPG123_ENC_ALAW_8 = 0x08 |
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| 69 | /* 0001 0001 1000 0000 signed 32 bit */ |
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| 70 | , MPG123_ENC_SIGNED_32 = MPG123_ENC_32|MPG123_ENC_SIGNED|0x1000 |
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| 71 | /* 0010 0001 0000 0000 unsigned 32 bit */ |
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| 72 | , MPG123_ENC_UNSIGNED_32 = MPG123_ENC_32|0x2000 |
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| 73 | /* 0101 0000 1000 0000 signed 24 bit */ |
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| 74 | , MPG123_ENC_SIGNED_24 = MPG123_ENC_24|MPG123_ENC_SIGNED|0x1000 |
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| 75 | /* 0110 0000 0000 0000 unsigned 24 bit */ |
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| 76 | , MPG123_ENC_UNSIGNED_24 = MPG123_ENC_24|0x2000 |
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| 77 | /* 0000 0010 0000 0000 32bit float */ |
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| 78 | , MPG123_ENC_FLOAT_32 = 0x200 |
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| 79 | /* 0000 0100 0000 0000 64bit float */ |
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| 80 | , MPG123_ENC_FLOAT_64 = 0x400 |
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| 81 | /* Any possibly known encoding from the list above. */ |
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| 82 | , MPG123_ENC_ANY = ( MPG123_ENC_SIGNED_16 | MPG123_ENC_UNSIGNED_16 |
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| 83 | | MPG123_ENC_UNSIGNED_8 | MPG123_ENC_SIGNED_8 |
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| 84 | | MPG123_ENC_ULAW_8 | MPG123_ENC_ALAW_8 |
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| 85 | | MPG123_ENC_SIGNED_32 | MPG123_ENC_UNSIGNED_32 |
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| 86 | | MPG123_ENC_SIGNED_24 | MPG123_ENC_UNSIGNED_24 |
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| 87 | | MPG123_ENC_FLOAT_32 | MPG123_ENC_FLOAT_64 ) |
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| 88 | }; |
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| 89 | |||
| 90 | /** Get size of one PCM sample with given encoding. |
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| 91 | * This is included both in libmpg123 and libout123. Both offer |
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| 92 | * an API function to provide the macro results from library |
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| 93 | * compile-time, not that of you application. This most likely |
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| 94 | * does not matter as I do not expect any fresh PCM sample |
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| 95 | * encoding to appear. But who knows? Perhaps the encoding type |
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| 96 | * will be abused for funny things in future, not even plain PCM. |
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| 97 | * And, by the way: Thomas really likes the ?: operator. |
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| 98 | * \param enc the encoding (mpg123_enc_enum value) |
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| 99 | * \return size of one sample in bytes |
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| 100 | */ |
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| 101 | #define MPG123_SAMPLESIZE(enc) ( \ |
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| 102 | (enc) & MPG123_ENC_8 \ |
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| 103 | ? 1 \ |
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| 104 | : ( (enc) & MPG123_ENC_16 \ |
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| 105 | ? 2 \ |
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| 106 | : ( (enc) & MPG123_ENC_24 \ |
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| 107 | ? 3 \ |
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| 108 | : ( ( (enc) & MPG123_ENC_32 \ |
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| 109 | || (enc) == MPG123_ENC_FLOAT_32 ) \ |
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| 110 | ? 4 \ |
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| 111 | : ( (enc) == MPG123_ENC_FLOAT_64 \ |
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| 112 | ? 8 \ |
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| 113 | : 0 \ |
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| 114 | ) ) ) ) ) |
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| 115 | |||
| 116 | /** Structure defining an audio format. |
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| 117 | * Providing the members as individual function arguments to define a certain |
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| 118 | * output format is easy enough. This struct makes is more comfortable to deal |
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| 119 | * with a list of formats. |
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| 120 | * Negative values for the members might be used to communicate use of default |
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| 121 | * values. |
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| 122 | */ |
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| 123 | struct mpg123_fmt |
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| 124 | { |
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| 125 | long rate; /**< sampling rate in Hz */ |
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| 126 | int channels; /**< channel count */ |
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| 127 | /** encoding code, can be single value or bitwise or of members of |
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| 128 | * mpg123_enc_enum */ |
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| 129 | int encoding; |
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| 130 | }; |
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| 131 | |||
| 132 | /* @} */ |
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| 133 | |||
| 134 | #endif |
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| 135 |