stream.h

00001 /*
00002  * libmad - MPEG audio decoder library
00003  * Copyright (C) 2000-2004 Underbit Technologies, Inc.
00004  *
00005  * This program is free software; you can redistribute it and/or modify
00006  * it under the terms of the GNU General Public License as published by
00007  * the Free Software Foundation; either version 2 of the License, or
00008  * (at your option) any later version.
00009  *
00010  * This program is distributed in the hope that it will be useful,
00011  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013  * GNU General Public License for more details.
00014  *
00015  * You should have received a copy of the GNU General Public License
00016  * along with this program; if not, write to the Free Software
00017  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00018  *
00019  * $Id: stream.h,v 1.1 2010/11/23 20:12:57 andy Exp $
00020  */
00021 
00022 # ifndef LIBMAD_STREAM_H
00023 # define LIBMAD_STREAM_H
00024 
00025 # include "bit.h"
00026 
00027 # define MAD_BUFFER_GUARD   8
00028 # define MAD_BUFFER_MDLEN   (511 + 2048 + MAD_BUFFER_GUARD)
00029 
00030 enum mad_error {
00031   MAD_ERROR_NONE       = 0x0000,    /* no error */
00032 
00033   MAD_ERROR_BUFLEN     = 0x0001,    /* input buffer too small (or EOF) */
00034   MAD_ERROR_BUFPTR     = 0x0002,    /* invalid (null) buffer pointer */
00035 
00036   MAD_ERROR_NOMEM      = 0x0031,    /* not enough memory */
00037 
00038   MAD_ERROR_LOSTSYNC       = 0x0101,    /* lost synchronization */
00039   MAD_ERROR_BADLAYER       = 0x0102,    /* reserved header layer value */
00040   MAD_ERROR_BADBITRATE     = 0x0103,    /* forbidden bitrate value */
00041   MAD_ERROR_BADSAMPLERATE  = 0x0104,    /* reserved sample frequency value */
00042   MAD_ERROR_BADEMPHASIS    = 0x0105,    /* reserved emphasis value */
00043 
00044   MAD_ERROR_BADCRC     = 0x0201,    /* CRC check failed */
00045   MAD_ERROR_BADBITALLOC    = 0x0211,    /* forbidden bit allocation value */
00046   MAD_ERROR_BADSCALEFACTOR = 0x0221,    /* bad scalefactor index */
00047   MAD_ERROR_BADMODE        = 0x0222,    /* bad bitrate/mode combination */
00048   MAD_ERROR_BADFRAMELEN    = 0x0231,    /* bad frame length */
00049   MAD_ERROR_BADBIGVALUES   = 0x0232,    /* bad big_values count */
00050   MAD_ERROR_BADBLOCKTYPE   = 0x0233,    /* reserved block_type */
00051   MAD_ERROR_BADSCFSI       = 0x0234,    /* bad scalefactor selection info */
00052   MAD_ERROR_BADDATAPTR     = 0x0235,    /* bad main_data_begin pointer */
00053   MAD_ERROR_BADPART3LEN    = 0x0236,    /* bad audio data length */
00054   MAD_ERROR_BADHUFFTABLE   = 0x0237,    /* bad Huffman table select */
00055   MAD_ERROR_BADHUFFDATA    = 0x0238,    /* Huffman data overrun */
00056   MAD_ERROR_BADSTEREO      = 0x0239 /* incompatible block_type for JS */
00057 };
00058 
00059 # define MAD_RECOVERABLE(error) ((error) & 0xff00)
00060 
00061 struct mad_stream {
00062   unsigned char const *buffer;      /* input bitstream buffer */
00063   unsigned char const *bufend;      /* end of buffer */
00064   unsigned long skiplen;        /* bytes to skip before next frame */
00065 
00066   int sync;             /* stream sync found */
00067   unsigned long freerate;       /* free bitrate (fixed) */
00068 
00069   unsigned char const *this_frame;  /* start of current frame */
00070   unsigned char const *next_frame;  /* start of next frame */
00071   struct mad_bitptr ptr;        /* current processing bit pointer */
00072 
00073   struct mad_bitptr anc_ptr;        /* ancillary bits pointer */
00074   unsigned int anc_bitlen;      /* number of ancillary bits */
00075 
00076   unsigned char (*main_data)[MAD_BUFFER_MDLEN];
00077                     /* Layer III main_data() */
00078   unsigned int md_len;          /* bytes in main_data */
00079 
00080   int options;              /* decoding options (see below) */
00081   enum mad_error error;         /* error code (see above) */
00082 };
00083 
00084 enum {
00085   MAD_OPTION_IGNORECRC      = 0x0001,   /* ignore CRC errors */
00086   MAD_OPTION_HALFSAMPLERATE = 0x0002    /* generate PCM at 1/2 sample rate */
00087 # if 0  /* not yet implemented */
00088   MAD_OPTION_LEFTCHANNEL    = 0x0010,   /* decode left channel only */
00089   MAD_OPTION_RIGHTCHANNEL   = 0x0020,   /* decode right channel only */
00090   MAD_OPTION_SINGLECHANNEL  = 0x0030    /* combine channels */
00091 # endif
00092 };
00093 
00094 void mad_stream_init(struct mad_stream *);
00095 void mad_stream_finish(struct mad_stream *);
00096 
00097 # define mad_stream_options(stream, opts)  \
00098     ((void) ((stream)->options = (opts)))
00099 
00100 void mad_stream_buffer(struct mad_stream *,
00101                unsigned char const *, unsigned long);
00102 void mad_stream_skip(struct mad_stream *, unsigned long);
00103 
00104 int mad_stream_sync(struct mad_stream *);
00105 
00106 char const *mad_stream_errorstr(struct mad_stream const *);
00107 
00108 # endif