wsutil/mpeg-audio.h

   1 /* mpeg-audio.h
   2  *
   3  * MPEG Audio header dissection
   4  * Written by Shaun Jackman <sjackman@gmail.com>
   5  * Copyright 2007 Shaun Jackman
   6  *
   7  * $Id$
   8  *
   9  * Wiretap Library
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  */
  24
  25 #ifndef MPA_H
  26 #define MPA_H 1
  27
  28 #include "ws_symbol_export.h"
  29
  30 struct mpa {
  31         unsigned int emphasis   :2;
  32         unsigned int original   :1;
  33         unsigned int copyright  :1;
  34         unsigned int modeext    :2;
  35         unsigned int mode       :2;
  36         unsigned int priv       :1;
  37         unsigned int padding    :1;
  38         unsigned int frequency  :2;
  39         unsigned int bitrate    :4;
  40         unsigned int protection :1;
  41         unsigned int layer      :2;
  42         unsigned int version    :2;
  43         unsigned int sync       :11;
  44 };
  45
  46 #define MPA_UNMARSHAL_SYNC(n)       ((n) >> 21 & 0x7ff)
  47 #define MPA_UNMARSHAL_VERSION(n)    ((n) >> 19 & 0x3)
  48 #define MPA_UNMARSHAL_LAYER(n)      ((n) >> 17 & 0x3)
  49 #define MPA_UNMARSHAL_PROTECTION(n) ((n) >> 16 & 0x1)
  50 #define MPA_UNMARSHAL_BITRATE(n)    ((n) >> 12 & 0xf)
  51 #define MPA_UNMARSHAL_FREQUENCY(n)  ((n) >> 10 & 0x3)
  52 #define MPA_UNMARSHAL_PADDING(n)    ((n) >>  9 & 0x1)
  53 #define MPA_UNMARSHAL_PRIVATE(n)    ((n) >>  8 & 0x1)
  54 #define MPA_UNMARSHAL_MODE(n)       ((n) >>  6 & 0x3)
  55 #define MPA_UNMARSHAL_MODEEXT(n)    ((n) >>  4 & 0x3)
  56 #define MPA_UNMARSHAL_COPYRIGHT(n)  ((n) >>  3 & 0x1)
  57 #define MPA_UNMARSHAL_ORIGINAL(n)   ((n) >>  2 & 0x1)
  58 #define MPA_UNMARSHAL_EMPHASIS(n)   ((n) >>  0 & 0x3)
  59
  60 #define MPA_UNMARSHAL(mpa, n) do { \
  61         (mpa)->sync       = MPA_UNMARSHAL_SYNC(n);       \
  62         (mpa)->version    = MPA_UNMARSHAL_VERSION(n);    \
  63         (mpa)->layer      = MPA_UNMARSHAL_LAYER(n);      \
  64         (mpa)->protection = MPA_UNMARSHAL_PROTECTION(n); \
  65         (mpa)->bitrate    = MPA_UNMARSHAL_BITRATE(n);    \
  66         (mpa)->frequency  = MPA_UNMARSHAL_FREQUENCY(n);  \
  67         (mpa)->padding    = MPA_UNMARSHAL_PADDING(n);    \
  68         (mpa)->priv       = MPA_UNMARSHAL_PRIVATE(n);    \
  69         (mpa)->mode       = MPA_UNMARSHAL_MODE(n);       \
  70         (mpa)->modeext    = MPA_UNMARSHAL_MODEEXT(n);    \
  71         (mpa)->copyright  = MPA_UNMARSHAL_COPYRIGHT(n);  \
  72         (mpa)->original   = MPA_UNMARSHAL_ORIGINAL(n);   \
  73         (mpa)->emphasis   = MPA_UNMARSHAL_EMPHASIS(n);   \
  74         } while (0)
  75
  76 WS_DLL_PUBLIC
  77 int mpa_version(const struct mpa *);
  78 WS_DLL_PUBLIC
  79 int mpa_layer(const struct mpa *);
  80 WS_DLL_PUBLIC
  81 unsigned int mpa_samples(const struct mpa *);
  82 WS_DLL_PUBLIC
  83 unsigned int mpa_bitrate(const struct mpa *);
  84 WS_DLL_PUBLIC
  85 unsigned int mpa_frequency(const struct mpa *);
  86 WS_DLL_PUBLIC
  87 unsigned int mpa_padding(const struct mpa *);
  88
  89 #define MPA_DATA_BYTES(mpa) (mpa_bitrate(mpa) * mpa_samples(mpa) \
  90                 / mpa_frequency(mpa) / 8)
  91 #define MPA_BYTES(mpa) (MPA_DATA_BYTES(mpa) + mpa_padding(mpa))
  92 #define MPA_DURATION_NS(mpa) \
  93         (1000000000 / mpa_frequency(mpa) * mpa_samples(mpa))
  94
  95 enum { MPA_SYNC = 0x7ff };
  96
  97 #define MPA_SYNC_VALID(mpa)      ((mpa)->sync == MPA_SYNC)
  98 #define MPA_VERSION_VALID(mpa)   (mpa_version(mpa) >= 0)
  99 #define MPA_LAYER_VALID(mpa)     (mpa_layer(mpa) >= 0)
 100 #define MPA_BITRATE_VALID(mpa)   (mpa_bitrate(mpa) > 0)
 101 #define MPA_FREQUENCY_VALID(mpa) (mpa_frequency(mpa) > 0)
 102 #define MPA_VALID(mpa) (MPA_SYNC_VALID(mpa) \
 103                 && MPA_VERSION_VALID(mpa) && MPA_LAYER_VALID(mpa) \
 104                 && MPA_BITRATE_VALID(mpa) && MPA_FREQUENCY_VALID(mpa))
 105
 106 #endif