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/* mpeg-audio.h
*
* MPEG Audio header dissection
* Written by Shaun Jackman <sjackman@gmail.com>
* Copyright 2007 Shaun Jackman
*
* $Id$
*
* Wiretap Library
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPA_H
#define MPA_H 1
struct mpa {
unsigned emphasis :2;
unsigned original :1;
unsigned copyright :1;
unsigned modeext :2;
unsigned mode :2;
unsigned private :1;
unsigned padding :1;
unsigned frequency :2;
unsigned bitrate :4;
unsigned protection :1;
unsigned layer :2;
unsigned version :2;
unsigned sync :11;
};
#define MPA_UNMARSHAL_SYNC(n) ((n) >> 21 & 0x7ff)
#define MPA_UNMARSHAL_VERSION(n) ((n) >> 19 & 0x3)
#define MPA_UNMARSHAL_LAYER(n) ((n) >> 17 & 0x3)
#define MPA_UNMARSHAL_PROTECTION(n) ((n) >> 16 & 0x1)
#define MPA_UNMARSHAL_BITRATE(n) ((n) >> 12 & 0xf)
#define MPA_UNMARSHAL_FREQUENCY(n) ((n) >> 10 & 0x3)
#define MPA_UNMARSHAL_PADDING(n) ((n) >> 9 & 0x1)
#define MPA_UNMARSHAL_PRIVATE(n) ((n) >> 8 & 0x1)
#define MPA_UNMARSHAL_MODE(n) ((n) >> 6 & 0x3)
#define MPA_UNMARSHAL_MODEEXT(n) ((n) >> 4 & 0x3)
#define MPA_UNMARSHAL_COPYRIGHT(n) ((n) >> 3 & 0x1)
#define MPA_UNMARSHAL_ORIGINAL(n) ((n) >> 2 & 0x1)
#define MPA_UNMARSHAL_EMPHASIS(n) ((n) >> 0 & 0x3)
#define MPA_UNMARSHAL(mpa, n) do { \
(mpa)->sync = MPA_UNMARSHAL_SYNC(n); \
(mpa)->version = MPA_UNMARSHAL_VERSION(n); \
(mpa)->layer = MPA_UNMARSHAL_LAYER(n); \
(mpa)->protection = MPA_UNMARSHAL_PROTECTION(n); \
(mpa)->bitrate = MPA_UNMARSHAL_BITRATE(n); \
(mpa)->frequency = MPA_UNMARSHAL_FREQUENCY(n); \
(mpa)->padding = MPA_UNMARSHAL_PADDING(n); \
(mpa)->private = MPA_UNMARSHAL_PRIVATE(n); \
(mpa)->mode = MPA_UNMARSHAL_MODE(n); \
(mpa)->modeext = MPA_UNMARSHAL_MODEEXT(n); \
(mpa)->copyright = MPA_UNMARSHAL_COPYRIGHT(n); \
(mpa)->original = MPA_UNMARSHAL_ORIGINAL(n); \
(mpa)->emphasis = MPA_UNMARSHAL_EMPHASIS(n); \
} while (0)
int mpa_version(const struct mpa *);
int mpa_layer(const struct mpa *);
unsigned mpa_samples(const struct mpa *);
unsigned mpa_bitrate(const struct mpa *);
unsigned mpa_frequency(const struct mpa *);
unsigned mpa_padding(const struct mpa *);
#define MPA_DATA_BYTES(mpa) (mpa_bitrate(mpa) * mpa_samples(mpa) \
/ mpa_frequency(mpa) / 8)
#define MPA_BYTES(mpa) (MPA_DATA_BYTES(mpa) + mpa_padding(mpa))
#define MPA_DURATION_NS(mpa) \
(1000000000 / mpa_frequency(mpa) * mpa_samples(mpa))
enum { MPA_SYNC = 0x7ff };
#define MPA_SYNC_VALID(mpa) ((mpa)->sync == MPA_SYNC)
#define MPA_VERSION_VALID(mpa) (mpa_version(mpa) >= 0)
#define MPA_LAYER_VALID(mpa) (mpa_layer(mpa) >= 0)
#define MPA_BITRATE_VALID(mpa) (mpa_bitrate(mpa) > 0)
#define MPA_FREQUENCY_VALID(mpa) (mpa_frequency(mpa) > 0)
#define MPA_VALID(mpa) (MPA_SYNC_VALID(mpa) \
&& MPA_VERSION_VALID(mpa) && MPA_LAYER_VALID(mpa) \
&& MPA_BITRATE_VALID(mpa) && MPA_FREQUENCY_VALID(mpa))
#endif
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