OLD | NEW |
1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 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_BASE_CHANNEL_MIXER_H_ | 5 #ifndef MEDIA_BASE_CHANNEL_MIXER_H_ |
6 #define MEDIA_BASE_CHANNEL_MIXER_H_ | 6 #define MEDIA_BASE_CHANNEL_MIXER_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/channel_layout.h" | 11 #include "media/base/channel_layout.h" |
12 #include "media/base/media_export.h" | 12 #include "media/base/media_export.h" |
13 | 13 |
14 namespace media { | 14 namespace media { |
15 | 15 |
16 class AudioBus; | 16 class AudioBus; |
17 class AudioParameters; | |
18 | 17 |
19 // ChannelMixer is for converting audio between channel layouts. The conversion | 18 // ChannelMixer is for converting audio between channel layouts. The conversion |
20 // matrix is built upon construction and used during each Transform() call. The | 19 // matrix is built upon construction and used during each Transform() call. The |
21 // algorithm works by generating a conversion matrix mapping each output channel | 20 // algorithm works by generating a conversion matrix mapping each output channel |
22 // to list of input channels. The transform renders all of the output channels, | 21 // to list of input channels. The transform renders all of the output channels, |
23 // with each output channel rendered according to a weighted sum of the relevant | 22 // with each output channel rendered according to a weighted sum of the relevant |
24 // input channels as defined in the matrix. | 23 // input channels as defined in the matrix. |
25 class MEDIA_EXPORT ChannelMixer { | 24 class MEDIA_EXPORT ChannelMixer { |
26 public: | 25 public: |
27 ChannelMixer(ChannelLayout input_layout, ChannelLayout output_layout); | 26 ChannelMixer(ChannelLayout input, ChannelLayout output); |
28 ChannelMixer(const AudioParameters& input, const AudioParameters& output); | |
29 ~ChannelMixer(); | 27 ~ChannelMixer(); |
30 | 28 |
31 void Initialize(ChannelLayout input_layout, int input_channels, | |
32 ChannelLayout output_layout, int output_channels); | |
33 | |
34 // Transforms all channels from |input| into |output| channels. | 29 // Transforms all channels from |input| into |output| channels. |
35 void Transform(const AudioBus* input, AudioBus* output); | 30 void Transform(const AudioBus* input, AudioBus* output); |
36 | 31 |
37 private: | 32 private: |
38 // Constructor helper methods for managing unaccounted input channels. | 33 // Constructor helper methods for managing unaccounted input channels. |
39 void AccountFor(Channels ch); | 34 void AccountFor(Channels ch); |
40 bool IsUnaccounted(Channels ch); | 35 bool IsUnaccounted(Channels ch); |
41 | 36 |
42 // Helper methods for checking if |ch| exists in either |input_layout_| or | 37 // Helper methods for checking if |ch| exists in either |input_layout_| or |
43 // |output_layout_| respectively. | 38 // |output_layout_| respectively. |
(...skipping 20 matching lines...) Expand all Loading... |
64 // Optimization case for when we can simply remap the input channels to output | 59 // Optimization case for when we can simply remap the input channels to output |
65 // channels and don't need to do a multiply-accumulate loop over |matrix_|. | 60 // channels and don't need to do a multiply-accumulate loop over |matrix_|. |
66 bool remapping_; | 61 bool remapping_; |
67 | 62 |
68 DISALLOW_COPY_AND_ASSIGN(ChannelMixer); | 63 DISALLOW_COPY_AND_ASSIGN(ChannelMixer); |
69 }; | 64 }; |
70 | 65 |
71 } // namespace media | 66 } // namespace media |
72 | 67 |
73 #endif // MEDIA_BASE_CHANNEL_MIXER_H_ | 68 #endif // MEDIA_BASE_CHANNEL_MIXER_H_ |
OLD | NEW |