afh.h

   1 /*
   2  * Copyright (C) 2005-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file afh.h structures for audio format handling (para_server) */
   8
   9 /** \cond */
  10 #ifdef HAVE_OGGVORBIS
  11 #define OV_AUDIO_FORMAT " ogg"
  12 #else
  13 #define OV_AUDIO_FORMAT ""
  14 #endif
  15
  16 #ifdef HAVE_FAAD
  17 #define AAC_AUDIO_FORMAT " aac"
  18 #else
  19 #define AAC_AUDIO_FORMAT ""
  20 #endif
  21
  22 #define SUPPORTED_AUDIO_FORMATS "mp3" OV_AUDIO_FORMAT AAC_AUDIO_FORMAT
  23
  24 /** \endcond */
  25
  26 /** size of the  audio_file info string */
  27 #define AUDIO_FILE_INFO_SIZE 256
  28
  29 /**
  30  * Audio format dependent information. Details vary between each audio format
  31  * handler.
  32  */
  33 struct audio_format_info {
  34         /** The number of chunks this audio file contains. */
  35         long unsigned chunks_total;
  36         /** The length of the audio file in seconds. */
  37         long unsigned seconds_total;
  38         /** A string that gets filled in by the audio format handler. */
  39         char info_string[AUDIO_FILE_INFO_SIZE];
  40         /**
  41          * The table that specifies the offset of the individual pieces in
  42          * the current audio file.
  43          */
  44         uint32_t *chunk_table;
  45         /** Period of time between sending data chunks. */
  46         struct timeval chunk_tv;
  47         /** End of file timeout - Do not load new audio file until this time. */
  48         struct timeval eof_tv;
  49         /**
  50          * The header is needed by senders in case a new client connects in the
  51          * middle of the stream. The length of the header defaults to zero
  52          * which means that this audio format does not need any special header
  53          * treatment. The audio format handler does not need to set this to
  54          * zero in this case.
  55          */
  56         unsigned header_len;
  57         /**
  58          * The position of the header within the audio file. Ignored if \a
  59          * header_len equals zero.
  60          */
  61         unsigned header_offset;
  62         /** The number of channels. */
  63         uint8_t channels;
  64         /** Frquency on Hz. */
  65         uint16_t frequency;
  66         /** Exact meaning depends on audio format. */
  67         uint16_t bitrate;
  68 };
  69
  70 /**
  71  *  Structure for audio format handling.
  72  *
  73  *  There's one such struct for each supported audio format. Initially, only \a
  74  *  name and \a init are defined. During the startup process, para_server calls
  75  *  the \a init function of each audio format handler which is expected to fill
  76  *  in the other part of this struct.
  77  */
  78 struct audio_format_handler {
  79         /** Name of the audio format. */
  80         const char *name;
  81         /**
  82          * Pointer to the audio format handler's init function.
  83          *
  84          * Must initialize all function pointers and is assumed to succeed.
  85          */
  86         void (*init)(struct audio_format_handler*);
  87         /** Typical file endings for files that can be handled by this afh. */
  88         const char **suffixes;
  89         /**
  90          * Check if this audio format handler can handle the file.
  91          *
  92          * This is a  pointer to a function returning whether a given file is
  93          * valid for this audio format. A negative return value indicates that
  94          * this audio format handler is unable to decode the given file. On
  95          * success, the function must return a positive value and fill in the
  96          * given struct audio_format_info.
  97          *
  98          * \sa struct audio_format_info
  99          */
 100         int (*get_file_info)(char *map, size_t numbytes,
 101                 struct audio_format_info *afi);
 102 };
 103
 104 void afh_init(void);
 105 int guess_audio_format(const char *name);
 106 int compute_afhi(const char *path, char *data, size_t size,
 107         struct audio_format_info *afhi);
 108 const char *audio_format_name(int);