1 /*

     2 * Copyright (c) 2010 Ixonos Plc.

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of the "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - Initial contribution

    11 *

    12 * Contributors:

    13 * Ixonos Plc

    14 *

    15 * Description:

    16 *

    17 */

    18 

    19 

    20 /**************************************************************************

    21   mpheader.h - MPEG-1 and MPEG-2 bit field (header) parsing functions.

    22 

    23   Author(s): Juha Ojanpera

    24   Copyright (c) 1999-2004 by Nokia Research Center, Speech and Audio Systems.

    25   *************************************************************************/

    26 

    27 #ifndef MPHEADER_H_

    28 #define MPHEADER_H_

    29 

    30 /*-- Project Headers. --*/

    31 #include "mpaud.h"

    32 #include "mp3tables.h"

    33 #include "defines.h"

    34 

    35 /* Checks whether window switching is used in layer III. */

    36 inline BOOL win_switch(TGranule_Info *gr_info)

    37 { return ((BOOL)(gr_info->flags & WINDOW_SWITCHING_FLAG)); }

    38 

    39 /* Checks whether short blocks are used in layer III. */

    40 inline BOOL short_block(TGranule_Info *gr_info)

    41 { return ((gr_info->flags & 3) == 2); }

    42 

    43 /* Checks whether mixed blocks are present in layer III. */

    44 inline BOOL mixed_block(TGranule_Info *gr_info)

    45 { return ((BOOL)(gr_info->flags & MIXED_BLOCK_FLAG)); }

    46 

    47 /* Checks whether 'scalefac_scale' bit is set in layer III. */

    48 inline BOOL scalefac_scale(TGranule_Info *gr_info)

    49 { return ((BOOL)((gr_info->flags & SCALEFAC_SCALE) ? 1 : 0)); }

    50 

    51 /* Returns the status of 'pre_flag' bit of layer III. */

    52 inline BOOL pre_flag(TGranule_Info *gr_info)

    53 { return ((BOOL)((gr_info->flags & PRE_FLAG) ? 1 : 0)); }

    54 

    55 /*-- Common header parsing functions. --*/

    56 

    57 /* MPEG-1 or MPEG-2 */

    58 inline int16 version(TMPEG_Header *mpheader)

    59 {return ((BOOL)((mpheader->header >> 19) & 1));}

    60 

    61 /* Checks whether the current stream is of type MPEG-2.5. */

    62 inline BOOL mp25version(TMPEG_Header *mpheader)

    63 { return ((BOOL)((mpheader->header & 0x100000) ? FALSE : TRUE)); }

    64 

    65 /* Layer (1, 2 or 3) */

    66 inline int16 layer_number(TMPEG_Header *mpheader)

    67 { return (int16)((4 - (mpheader->header >> 17) & 3)); }

    68 

    69 /* Checks if error protection is used in the bitstream. */

    70 inline BOOL error_protection(TMPEG_Header *mpheader)

    71 { return (!((mpheader->header >> 16) & 1)); }

    72 

    73 /* Sampling frequency index */

    74 inline int16 sfreq(TMPEG_Header *mpheader)

    75 { return (int16)((mpheader->header >> 10) & 3);}

    76 

    77 /* Checks whether padding bit is set. */

    78 inline BOOL padding(TMPEG_Header *mpheader)

    79 { return (BOOL)((mpheader->header >> 9) & 1); }

    80   

    81 /* Checks if private bit is set. */

    82 inline BOOL private_bit(TMPEG_Header *mpheader)

    83 { return (BOOL)((mpheader->header >> 8) & 1); }

    84   

    85 /* Mono, stereo, joint or dual */

    86 inline int16 mode(TMPEG_Header *mpheader)

    87 { return (int16)((mpheader->header >> 6) & 3); }

    88 

    89 /* Value of mode extension field */

    90 inline int16 mode_extension(TMPEG_Header *mpheader)

    91 { return (int16)((mpheader->header >> 4) & 3); }

    92 

    93 /* Checks whether copyright bit is set. */

    94 inline BOOL copyright(TMPEG_Header *mpheader)

    95 { return (BOOL)((mpheader->header >> 3) & 1); }

    96   

    97 /* Checks whether original bit. */

    98 inline BOOL original(TMPEG_Header *mpheader)

    99 { return (BOOL)((mpheader->header >> 2) & 1); }

   100 

   101 /* Value of bitrate field */

   102 inline int16 bit_rate_idx(TMPEG_Header *mpheader) 

   103 { return ((int16)((mpheader->header >> 12) & 0xF)); }

   104 

   105 /* Bitrate */

   106 inline int16 bit_rate(TMPEG_Header *mpheader)

   107 { return (bitrate[version(mpheader)][(int16)((mpheader->header >> 12) & 0xF)]); }

   108 

   109 /* Number of channels; 1 for mono, 2 for stereo */

   110 inline int16 channels(TMPEG_Header *mpheader)

   111 { return ((int16)((mode(mpheader) == MPG_MD_MONO) ? (int16)1 : (int16)2));}

   112 

   113 inline const int16 *GetBitRateTable(TMPEG_Header *mpheader)

   114 { return (&bitrate[version(mpheader)][0]); }

   115 

   116 /* Sampling frequency */

   117 inline int32 frequency(TMPEG_Header *mpheader)

   118 { return (s_freq[(mpheader->header & 0x100000) ? version(mpheader):2][sfreq(mpheader)]); }

   119 

   120 /* Frame length in milliseconds */

   121 inline int32 GetFrameTime(TMPEG_Header *mpheader)

   122 { return (framelength[sfreq(mpheader) + (mp25version(mpheader)) * 3]); }

   123 

   124 #endif /* MPHEADER_H_ */