stream.h

/*
 * libmad - MPEG audio decoder library
 * Copyright (C) 2000-2003 Underbit Technologies, Inc.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * $Id: stream.h,v 1.1 2003/08/31 19:00:15 gabest Exp $
 */

# ifndef LIBMAD_STREAM_H
# define LIBMAD_STREAM_H

# include "bit.h"

# define MAD_BUFFER_GUARD       8
# define MAD_BUFFER_MDLEN       (511 + 2048 + MAD_BUFFER_GUARD)

enum mad_error {
  MAD_ERROR_NONE           = 0x0000,    /* no error */

  MAD_ERROR_BUFLEN         = 0x0001,    /* input buffer too small (or EOF) */
  MAD_ERROR_BUFPTR         = 0x0002,    /* invalid (null) buffer pointer */

  MAD_ERROR_NOMEM          = 0x0031,    /* not enough memory */

  MAD_ERROR_LOSTSYNC       = 0x0101,    /* lost synchronization */
  MAD_ERROR_BADLAYER       = 0x0102,    /* reserved header layer value */
  MAD_ERROR_BADBITRATE     = 0x0103,    /* forbidden bitrate value */
  MAD_ERROR_BADSAMPLERATE  = 0x0104,    /* reserved sample frequency value */
  MAD_ERROR_BADEMPHASIS    = 0x0105,    /* reserved emphasis value */

  MAD_ERROR_BADCRC         = 0x0201,    /* CRC check failed */
  MAD_ERROR_BADBITALLOC    = 0x0211,    /* forbidden bit allocation value */
  MAD_ERROR_BADSCALEFACTOR = 0x0221,    /* bad scalefactor index */
  MAD_ERROR_BADFRAMELEN    = 0x0231,    /* bad frame length */
  MAD_ERROR_BADBIGVALUES   = 0x0232,    /* bad big_values count */
  MAD_ERROR_BADBLOCKTYPE   = 0x0233,    /* reserved block_type */
  MAD_ERROR_BADSCFSI       = 0x0234,    /* bad scalefactor selection info */
  MAD_ERROR_BADDATAPTR     = 0x0235,    /* bad main_data_begin pointer */
  MAD_ERROR_BADPART3LEN    = 0x0236,    /* bad audio data length */
  MAD_ERROR_BADHUFFTABLE   = 0x0237,    /* bad Huffman table select */
  MAD_ERROR_BADHUFFDATA    = 0x0238,    /* Huffman data overrun */
  MAD_ERROR_BADSTEREO      = 0x0239     /* incompatible block_type for JS */
};

# define MAD_RECOVERABLE(error) ((error) & 0xff00)

struct mad_stream {
  unsigned char const *buffer;          /* input bitstream buffer */
  unsigned char const *bufend;          /* end of buffer */
  unsigned long skiplen;                /* bytes to skip before next frame */

  int sync;                             /* stream sync found */
  unsigned long freerate;               /* free bitrate (fixed) */

  unsigned char const *this_frame;      /* start of current frame */
  unsigned char const *next_frame;      /* start of next frame */
  struct mad_bitptr ptr;                /* current processing bit pointer */

  struct mad_bitptr anc_ptr;            /* ancillary bits pointer */
  unsigned int anc_bitlen;              /* number of ancillary bits */

  unsigned char (*main_data)[MAD_BUFFER_MDLEN];
                                        /* Layer III main_data() */
  unsigned int md_len;                  /* bytes in main_data */

  int options;                          /* decoding options (see below) */
  enum mad_error error;                 /* error code (see above) */
};

enum {
  MAD_OPTION_IGNORECRC      = 0x0001,   /* ignore CRC errors */
  MAD_OPTION_HALFSAMPLERATE = 0x0002    /* generate PCM at 1/2 sample rate */
# if 0  /* not yet implemented */
  MAD_OPTION_LEFTCHANNEL    = 0x0010,   /* decode left channel only */
  MAD_OPTION_RIGHTCHANNEL   = 0x0020,   /* decode right channel only */
  MAD_OPTION_SINGLECHANNEL  = 0x0030    /* combine channels */
# endif
};

void mad_stream_init(struct mad_stream *);
void mad_stream_finish(struct mad_stream *);

# define mad_stream_options(stream, opts)  \
    ((void) ((stream)->options = (opts)))

void mad_stream_buffer(struct mad_stream *,
                       unsigned char const *, unsigned long);
void mad_stream_skip(struct mad_stream *, unsigned long);

int mad_stream_sync(struct mad_stream *);

char const *mad_stream_errorstr(struct mad_stream const *);

# endif

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