1/***************************************************************************
2 copyright : (C) 2002 - 2008 by Scott Wheeler
3 email : wheeler@kde.org
4 ***************************************************************************/
5
6/***************************************************************************
7 * This library is free software; you can redistribute it and/or modify *
8 * it under the terms of the GNU Lesser General Public License version *
9 * 2.1 as published by the Free Software Foundation. *
10 * *
11 * This library is distributed in the hope that it will be useful, but *
12 * WITHOUT ANY WARRANTY; without even the implied warranty of *
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
14 * Lesser General Public License for more details. *
15 * *
16 * You should have received a copy of the GNU Lesser General Public *
17 * License along with this library; if not, write to the Free Software *
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA *
19 * 02110-1301 USA *
20 * *
21 * Alternatively, this file is available under the Mozilla Public *
22 * License Version 1.1. You may obtain a copy of the License at *
23 * http://www.mozilla.org/MPL/ *
24 ***************************************************************************/
25
26#ifndef TAGLIB_AUDIOPROPERTIES_H
27#define TAGLIB_AUDIOPROPERTIES_H
28
29#include "taglib_export.h"
30
31namespace TagLib {
32
33 //! A simple, abstract interface to common audio properties
34
35 /*!
36 * The values here are common to most audio formats. For more specific, codec
37 * dependent values, please see see the subclasses APIs. This is meant to
38 * compliment the TagLib::File and TagLib::Tag APIs in providing a simple
39 * interface that is sufficient for most applications.
40 */
41
42 class TAGLIB_EXPORT AudioProperties
43 {
44 public:
45
46 /*!
47 * Reading audio properties from a file can sometimes be very time consuming
48 * and for the most accurate results can often involve reading the entire
49 * file. Because in many situations speed is critical or the accuracy of the
50 * values is not particularly important this allows the level of desired
51 * accuracy to be set.
52 */
53 enum ReadStyle {
54 //! Read as little of the file as possible
55 Fast,
56 //! Read more of the file and make better values guesses
57 Average,
58 //! Read as much of the file as needed to report accurate values
59 Accurate
60 };
61
62 /*!
63 * Destroys this AudioProperties instance.
64 */
65 virtual ~AudioProperties();
66
67 /*!
68 * Returns the length of the file in seconds.
69 */
70 virtual int length() const = 0;
71
72 /*!
73 * Returns the length of the file in seconds. The length is rounded down to
74 * the nearest whole second.
75 *
76 * \see lengthInMilliseconds()
77 */
78 // BIC: make virtual
79 int lengthInSeconds() const;
80
81 /*!
82 * Returns the length of the file in milliseconds.
83 *
84 * \see lengthInSeconds()
85 */
86 // BIC: make virtual
87 int lengthInMilliseconds() const;
88
89 /*!
90 * Returns the most appropriate bit rate for the file in kb/s. For constant
91 * bitrate formats this is simply the bitrate of the file. For variable
92 * bitrate formats this is either the average or nominal bitrate.
93 */
94 virtual int bitrate() const = 0;
95
96 /*!
97 * Returns the sample rate in Hz.
98 */
99 virtual int sampleRate() const = 0;
100
101 /*!
102 * Returns the number of audio channels.
103 */
104 virtual int channels() const = 0;
105
106 protected:
107
108 /*!
109 * Construct an audio properties instance. This is protected as this class
110 * should not be instantiated directly, but should be instantiated via its
111 * subclasses and can be fetched from the FileRef or File APIs.
112 *
113 * \see ReadStyle
114 */
115 AudioProperties(ReadStyle style);
116
117 private:
118 AudioProperties(const AudioProperties &);
119 AudioProperties &operator=(const AudioProperties &);
120
121 class AudioPropertiesPrivate;
122 AudioPropertiesPrivate *d;
123 };
124
125}
126
127#endif
128