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Side by Side Diff: media/audio/audio_util.h

Issue 7572040: Enable media.dll / libmedia.so. (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src/
Patch Set: '' Created 9 years, 4 months ago
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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be 2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file. 3 // found in the LICENSE file.
4 4
5 #ifndef MEDIA_AUDIO_AUDIO_UTIL_H_ 5 #ifndef MEDIA_AUDIO_AUDIO_UTIL_H_
6 #define MEDIA_AUDIO_AUDIO_UTIL_H_ 6 #define MEDIA_AUDIO_AUDIO_UTIL_H_
7 7
8 #include <vector> 8 #include <vector>
9 9
10 #include "base/basictypes.h" 10 #include "base/basictypes.h"
11 #include "media/base/media_export.h"
11 12
12 namespace media { 13 namespace media {
13 14
14 // For all audio functions 3 audio formats are supported: 15 // For all audio functions 3 audio formats are supported:
15 // 8 bits unsigned 0 to 255. 16 // 8 bits unsigned 0 to 255.
16 // 16 bit signed (little endian). 17 // 16 bit signed (little endian).
17 // 32 bit signed (little endian) 18 // 32 bit signed (little endian)
18 19
19 // AdjustVolume() does a software volume adjustment of a sample buffer. 20 // AdjustVolume() does a software volume adjustment of a sample buffer.
20 // The samples are multiplied by the volume, which should range from 21 // The samples are multiplied by the volume, which should range from
21 // 0.0 (mute) to 1.0 (full volume). 22 // 0.0 (mute) to 1.0 (full volume).
22 // Using software allows each audio and video to have its own volume without 23 // Using software allows each audio and video to have its own volume without
23 // affecting the master volume. 24 // affecting the master volume.
24 // In the future the function may be used to adjust the sample format to 25 // In the future the function may be used to adjust the sample format to
25 // simplify hardware requirements and to support a wider variety of input 26 // simplify hardware requirements and to support a wider variety of input
26 // formats. 27 // formats.
27 // The buffer is modified in-place to avoid memory management, as this 28 // The buffer is modified in-place to avoid memory management, as this
28 // function may be called in performance critical code. 29 // function may be called in performance critical code.
29 bool AdjustVolume(void* buf, 30 MEDIA_EXPORT bool AdjustVolume(void* buf,
30 size_t buflen, 31 size_t buflen,
31 int channels, 32 int channels,
32 int bytes_per_sample, 33 int bytes_per_sample,
33 float volume); 34 float volume);
34 35
35 // FoldChannels() does a software multichannel folding down to stereo. 36 // FoldChannels() does a software multichannel folding down to stereo.
36 // Channel order is assumed to be 5.1 Dolby standard which is 37 // Channel order is assumed to be 5.1 Dolby standard which is
37 // front left, front right, center, surround left, surround right. 38 // front left, front right, center, surround left, surround right.
38 // The subwoofer is ignored. 39 // The subwoofer is ignored.
39 // 6.1 adds a rear center speaker, and 7.1 has 2 rear speakers. These 40 // 6.1 adds a rear center speaker, and 7.1 has 2 rear speakers. These
40 // channels are rare and ignored. 41 // channels are rare and ignored.
41 // After summing the channels, volume is adjusted and the samples are 42 // After summing the channels, volume is adjusted and the samples are
42 // clipped to the maximum value. 43 // clipped to the maximum value.
43 // Volume should normally range from 0.0 (mute) to 1.0 (full volume), but 44 // Volume should normally range from 0.0 (mute) to 1.0 (full volume), but
44 // since clamping is performed a value of more than 1 is allowed to increase 45 // since clamping is performed a value of more than 1 is allowed to increase
45 // volume. 46 // volume.
46 // The buffer is modified in-place to avoid memory management, as this 47 // The buffer is modified in-place to avoid memory management, as this
47 // function may be called in performance critical code. 48 // function may be called in performance critical code.
48 bool FoldChannels(void* buf, 49 MEDIA_EXPORT bool FoldChannels(void* buf,
49 size_t buflen, 50 size_t buflen,
50 int channels, 51 int channels,
51 int bytes_per_sample, 52 int bytes_per_sample,
52 float volume); 53 float volume);
53 54
54 // DeinterleaveAudioChannel() takes interleaved audio buffer |source| 55 // DeinterleaveAudioChannel() takes interleaved audio buffer |source|
55 // of the given |sample_fmt| and |number_of_channels| and extracts 56 // of the given |sample_fmt| and |number_of_channels| and extracts
56 // |number_of_frames| data for the given |channel_index| and 57 // |number_of_frames| data for the given |channel_index| and
57 // puts it in the floating point |destination|. 58 // puts it in the floating point |destination|.
58 // It returns |true| on success, or |false| if the |sample_fmt| is 59 // It returns |true| on success, or |false| if the |sample_fmt| is
59 // not recognized. 60 // not recognized.
60 bool DeinterleaveAudioChannel(void* source, 61 bool DeinterleaveAudioChannel(void* source,
61 float* destination, 62 float* destination,
62 int channels, 63 int channels,
63 int channel_index, 64 int channel_index,
64 int bytes_per_sample, 65 int bytes_per_sample,
65 size_t number_of_frames); 66 size_t number_of_frames);
66 67
67 // InterleaveFloatToInt16 scales, clips, and interleaves the planar 68 // InterleaveFloatToInt16 scales, clips, and interleaves the planar
68 // floating-point audio contained in |source| to the int16 |destination|. 69 // floating-point audio contained in |source| to the int16 |destination|.
69 // The floating-point data is in a canonical range of -1.0 -> +1.0. 70 // The floating-point data is in a canonical range of -1.0 -> +1.0.
70 // The size of the |source| vector determines the number of channels. 71 // The size of the |source| vector determines the number of channels.
71 // The |destination| buffer is assumed to be large enough to hold the 72 // The |destination| buffer is assumed to be large enough to hold the
72 // result. Thus it must be at least size: number_of_frames * source.size() 73 // result. Thus it must be at least size: number_of_frames * source.size()
73 void InterleaveFloatToInt16(const std::vector<float*>& source, 74 MEDIA_EXPORT void InterleaveFloatToInt16(const std::vector<float*>& source,
74 int16* destination, 75 int16* destination,
75 size_t number_of_frames); 76 size_t number_of_frames);
76 77
77 // Returns the default audio hardware sample-rate. 78 // Returns the default audio hardware sample-rate.
78 double GetAudioHardwareSampleRate(); 79 MEDIA_EXPORT double GetAudioHardwareSampleRate();
79 80
80 } // namespace media 81 } // namespace media
81 82
82 #endif // MEDIA_AUDIO_AUDIO_UTIL_H_ 83 #endif // MEDIA_AUDIO_AUDIO_UTIL_H_
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