src/mp3.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
   2 /*
   3  * mp3.h: Mp3 for the media
   4  *
   5  * Contact:
   6  *   Moonlight List (moonlight-list@lists.ximian.com)
   7  *
   8  * Copyright 2008 Novell, Inc. (http://www.novell.com)
   9  *
  10  * See the LICENSE file included with the distribution for details.
  11  *
  12  */
  13
  14 #ifndef __MOON_MP3_H_
  15 #define __MOON_MP3_H_
  16
  17 #include <glib.h>
  18
  19 #include "pipeline.h"
  20
  21
  22 /* validate that this is an MPEG audio stream by checking that
  23  * the 32bit header matches the pattern:
  24  *
  25  * 1111 1111 111* **** **** **** **** **** = 0xff 0xe0
  26  *
  27  * Use a mask of 0xffe6 (because bits 12 and 13 can both be 0 if it is
  28  * MPEG 2.5). Compare the second byte > 0xe0 because one of the other
  29  * masked bits has to be set (the Layer bits cannot both be 0).
  30  */
  31 #define is_mpeg_header(buffer) (buffer[0] == 0xff && ((buffer[1] & 0xe6) > 0xe0) && (buffer[1] & 0x18) != 0x08)
  32
  33 struct MpegFrameHeader {
  34         guint8 version:2;
  35         guint8 layer:2;
  36
  37         guint8 copyright:1;
  38         guint8 original:1;
  39         guint8 padded:1;
  40         guint8 prot:1;
  41
  42         guint8 channels:6;
  43         guint8 intensity:1;
  44         guint8 ms:1;
  45
  46         gint32 bit_rate;
  47         gint32 sample_rate;
  48 };
  49
  50 enum MpegVBRHeaderType {
  51         MpegNoVBRHeader,
  52         MpegXingHeader,
  53         MpegVBRIHeader
  54 };
  55
  56 struct MpegVBRHeader {
  57         MpegVBRHeaderType type;
  58         guint32 nframes;
  59 };
  60
  61 struct MpegFrame {
  62         gint64 offset;
  63         guint64 pts;
  64         guint32 dur;
  65
  66         // this is needed in case this frame did not specify it's own
  67         // bit rate which is possible for MPEG-1 Layer 3 audio.
  68         gint32 bit_rate;
  69 };
  70
  71 class Mp3FrameReader {
  72         IMediaSource *source;
  73         AudioStream *stream;
  74         gint64 stream_start;
  75         guint32 frame_dur;
  76         guint32 frame_len;
  77         guint64 cur_pts;
  78         gint32 bit_rate;
  79         bool xing;
  80         bool sync_lost;
  81
  82         MpegFrame *jmptab;
  83         guint32 avail;
  84         guint32 used;
  85
  86         guint32 MpegFrameSearch (guint64 pts);
  87         void AddFrameIndex (gint64 offset, guint64 pts, guint32 dur, gint32 bit_rate);
  88
  89         MediaResult SkipFrame ();
  90
  91 public:
  92         Mp3FrameReader (IMediaSource *source, AudioStream *stream, gint64 start, guint32 frame_len, guint32 frame_duration, bool xing);
  93         ~Mp3FrameReader ();
  94
  95         MediaResult Seek (guint64 pts);
  96
  97         MediaResult TryReadFrame (MediaFrame **frame);
  98
  99         // FindMpegHeader
 100         //   Might change the current position of the source
 101         static MediaResult FindMpegHeader (MpegFrameHeader *mpeg, MpegVBRHeader *vbr, IMediaSource *source, gint64 start, gint64 *result);
 102 };
 103
 104 class Mp3Demuxer : public IMediaDemuxer {
 105 private:
 106         Mp3FrameReader *reader;
 107         bool xing;
 108
 109         MediaResult ReadHeader ();
 110
 111         static MediaResult GetFrameCallback (MediaClosure *closure);
 112
 113 protected:
 114         virtual ~Mp3Demuxer ();
 115
 116         virtual void GetFrameAsyncInternal (IMediaStream *stream);
 117         virtual void OpenDemuxerAsyncInternal ();
 118         virtual void SeekAsyncInternal (guint64 timeToSeek);
 119         virtual void SwitchMediaStreamAsyncInternal (IMediaStream *stream) {}; // An mp3 file has only 1 stream, so this doesn't make any sense
 120
 121 public:
 122         Mp3Demuxer (Media *media, IMediaSource *source);
 123
 124         virtual const char *GetName () { return "Mp3Demuxer"; }
 125 };
 126
 127 class Mp3DemuxerInfo : public DemuxerInfo {
 128 public:
 129         virtual MediaResult Supports (IMediaSource *source);
 130         virtual IMediaDemuxer *Create (Media *media, IMediaSource *source);
 131         virtual const char *GetName () { return "Mp3Demuxer"; }
 132 };
 133
 134 bool mpeg_parse_header (MpegFrameHeader *mpeg, const guint8 *buffer);
 135 double mpeg_frame_length (MpegFrameHeader *mpeg, bool xing);
 136
 137 #endif