wsutil/mpeg-audio.h

   1 /** @file
   2  *
   3  * MPEG Audio header dissection
   4  * Written by Shaun Jackman <sjackman@gmail.com>
   5  * Copyright 2007 Shaun Jackman
   6  *
   7  * Wiretap Library
   8  * SPDX-License-Identifier: GPL-2.0-or-later
   9  */
  10
  11 #ifndef MPA_H
  12 #define MPA_H 1
  13
  14 #include <stdint.h>
  15 #include "ws_symbol_export.h"
  16
  17 struct mpa {
  18         unsigned int emphasis   :2;
  19         unsigned int original   :1;
  20         unsigned int copyright  :1;
  21         unsigned int modeext    :2;
  22         unsigned int mode       :2;
  23         unsigned int priv       :1;
  24         unsigned int padding    :1;
  25         unsigned int frequency  :2;
  26         unsigned int bitrate    :4;
  27         unsigned int protection :1;
  28         unsigned int layer      :2;
  29         unsigned int version    :2;
  30         unsigned int sync       :11;
  31 };
  32
  33 #define MPA_UNMARSHAL_SYNC(n)       ((n) >> 21 & 0x7ff)
  34 #define MPA_UNMARSHAL_VERSION(n)    ((n) >> 19 & 0x3)
  35 #define MPA_UNMARSHAL_LAYER(n)      ((n) >> 17 & 0x3)
  36 #define MPA_UNMARSHAL_PROTECTION(n) ((n) >> 16 & 0x1)
  37 #define MPA_UNMARSHAL_BITRATE(n)    ((n) >> 12 & 0xf)
  38 #define MPA_UNMARSHAL_FREQUENCY(n)  ((n) >> 10 & 0x3)
  39 #define MPA_UNMARSHAL_PADDING(n)    ((n) >>  9 & 0x1)
  40 #define MPA_UNMARSHAL_PRIVATE(n)    ((n) >>  8 & 0x1)
  41 #define MPA_UNMARSHAL_MODE(n)       ((n) >>  6 & 0x3)
  42 #define MPA_UNMARSHAL_MODEEXT(n)    ((n) >>  4 & 0x3)
  43 #define MPA_UNMARSHAL_COPYRIGHT(n)  ((n) >>  3 & 0x1)
  44 #define MPA_UNMARSHAL_ORIGINAL(n)   ((n) >>  2 & 0x1)
  45 #define MPA_UNMARSHAL_EMPHASIS(n)   ((n) >>  0 & 0x3)
  46
  47 #define MPA_UNMARSHAL(mpa, n) do { \
  48         (mpa)->sync       = MPA_UNMARSHAL_SYNC(n);       \
  49         (mpa)->version    = MPA_UNMARSHAL_VERSION(n);    \
  50         (mpa)->layer      = MPA_UNMARSHAL_LAYER(n);      \
  51         (mpa)->protection = MPA_UNMARSHAL_PROTECTION(n); \
  52         (mpa)->bitrate    = MPA_UNMARSHAL_BITRATE(n);    \
  53         (mpa)->frequency  = MPA_UNMARSHAL_FREQUENCY(n);  \
  54         (mpa)->padding    = MPA_UNMARSHAL_PADDING(n);    \
  55         (mpa)->priv       = MPA_UNMARSHAL_PRIVATE(n);    \
  56         (mpa)->mode       = MPA_UNMARSHAL_MODE(n);       \
  57         (mpa)->modeext    = MPA_UNMARSHAL_MODEEXT(n);    \
  58         (mpa)->copyright  = MPA_UNMARSHAL_COPYRIGHT(n);  \
  59         (mpa)->original   = MPA_UNMARSHAL_ORIGINAL(n);   \
  60         (mpa)->emphasis   = MPA_UNMARSHAL_EMPHASIS(n);   \
  61         } while (0)
  62
  63 WS_DLL_PUBLIC
  64 int mpa_version(const struct mpa *);
  65 WS_DLL_PUBLIC
  66 int mpa_layer(const struct mpa *);
  67 WS_DLL_PUBLIC
  68 unsigned int mpa_samples(const struct mpa *);
  69 WS_DLL_PUBLIC
  70 unsigned int mpa_bitrate(const struct mpa *);
  71 WS_DLL_PUBLIC
  72 unsigned int mpa_frequency(const struct mpa *);
  73 WS_DLL_PUBLIC
  74 unsigned int mpa_padding(const struct mpa *);
  75 WS_DLL_PUBLIC
  76 uint32_t decode_synchsafe_int(uint32_t);
  77
  78 #define MPA_DATA_BYTES(mpa) (mpa_bitrate(mpa) * mpa_samples(mpa) \
  79                 / mpa_frequency(mpa) / 8)
  80 #define MPA_BYTES(mpa) (MPA_DATA_BYTES(mpa) + mpa_padding(mpa))
  81 #define MPA_DURATION_NS(mpa) \
  82         (1000000000 / mpa_frequency(mpa) * mpa_samples(mpa))
  83
  84 enum { MPA_SYNC = 0x7ff };
  85
  86 #define MPA_SYNC_VALID(mpa)      ((mpa)->sync == MPA_SYNC)
  87 #define MPA_VERSION_VALID(mpa)   (mpa_version(mpa) >= 0)
  88 #define MPA_LAYER_VALID(mpa)     (mpa_layer(mpa) >= 0)
  89 #define MPA_BITRATE_VALID(mpa)   (mpa_bitrate(mpa) > 0)
  90 #define MPA_FREQUENCY_VALID(mpa) (mpa_frequency(mpa) > 0)
  91 #define MPA_VALID(mpa) (MPA_SYNC_VALID(mpa) \
  92                 && MPA_VERSION_VALID(mpa) && MPA_LAYER_VALID(mpa) \
  93                 && MPA_BITRATE_VALID(mpa) && MPA_FREQUENCY_VALID(mpa))
  94
  95 #endif