1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef MEDIA_BASE_AUDIO_BUFFER_H_ 6 #define MEDIA_BASE_AUDIO_BUFFER_H_ 7 8 #include <vector> 9 10 #include "base/memory/aligned_memory.h" 11 #include "base/memory/ref_counted.h" 12 #include "base/memory/scoped_ptr.h" 13 #include "base/time/time.h" 14 #include "media/base/channel_layout.h" 15 #include "media/base/media_export.h" 16 #include "media/base/sample_format.h" 17 18 namespace media { 19 class AudioBus; 20 21 // An audio buffer that takes a copy of the data passed to it, holds it, and 22 // copies it into an AudioBus when needed. Also supports an end of stream 23 // marker. 24 class MEDIA_EXPORT AudioBuffer 25 : public base::RefCountedThreadSafe<AudioBuffer> { 26 public: 27 // Alignment of each channel's data; this must match what ffmpeg expects 28 // (which may be 0, 16, or 32, depending on the processor). Selecting 32 in 29 // order to work on all processors. 30 enum { kChannelAlignment = 32 }; 31 32 // Create an AudioBuffer whose channel data is copied from |data|. For 33 // interleaved data, only the first buffer is used. For planar data, the 34 // number of buffers must be equal to |channel_count|. |frame_count| is the 35 // number of frames in each buffer. |data| must not be null and |frame_count| 36 // must be >= 0. 37 static scoped_refptr<AudioBuffer> CopyFrom(SampleFormat sample_format, 38 ChannelLayout channel_layout, 39 int channel_count, 40 int sample_rate, 41 int frame_count, 42 const uint8* const* data, 43 const base::TimeDelta timestamp); 44 45 // Create an AudioBuffer with |frame_count| frames. Buffer is allocated, but 46 // not initialized. Timestamp and duration are set to kNoTimestamp(). 47 static scoped_refptr<AudioBuffer> CreateBuffer(SampleFormat sample_format, 48 ChannelLayout channel_layout, 49 int channel_count, 50 int sample_rate, 51 int frame_count); 52 53 // Create an empty AudioBuffer with |frame_count| frames. 54 static scoped_refptr<AudioBuffer> CreateEmptyBuffer( 55 ChannelLayout channel_layout, 56 int channel_count, 57 int sample_rate, 58 int frame_count, 59 const base::TimeDelta timestamp); 60 61 // Create a AudioBuffer indicating we've reached end of stream. 62 // Calling any method other than end_of_stream() on the resulting buffer 63 // is disallowed. 64 static scoped_refptr<AudioBuffer> CreateEOSBuffer(); 65 66 // Copy frames into |dest|. |frames_to_copy| is the number of frames to copy. 67 // |source_frame_offset| specifies how many frames in the buffer to skip 68 // first. |dest_frame_offset| is the frame offset in |dest|. The frames are 69 // converted from their source format into planar float32 data (which is all 70 // that AudioBus handles). 71 void ReadFrames(int frames_to_copy, 72 int source_frame_offset, 73 int dest_frame_offset, 74 AudioBus* dest); 75 76 // Trim an AudioBuffer by removing |frames_to_trim| frames from the start. 77 // Timestamp and duration are adjusted to reflect the fewer frames. 78 // Note that repeated calls to TrimStart() may result in timestamp() and 79 // duration() being off by a few microseconds due to rounding issues. 80 void TrimStart(int frames_to_trim); 81 82 // Trim an AudioBuffer by removing |frames_to_trim| frames from the end. 83 // Duration is adjusted to reflect the fewer frames. 84 void TrimEnd(int frames_to_trim); 85 86 // Trim an AudioBuffer by removing |end - start| frames from [|start|, |end|). 87 // Even if |start| is zero, timestamp() is not adjusted, only duration(). 88 void TrimRange(int start, int end); 89 90 // Return the number of channels. channel_count()91 int channel_count() const { return channel_count_; } 92 93 // Return the number of frames held. frame_count()94 int frame_count() const { return adjusted_frame_count_; } 95 96 // Return the sample rate. sample_rate()97 int sample_rate() const { return sample_rate_; } 98 99 // Return the channel layout. channel_layout()100 ChannelLayout channel_layout() const { return channel_layout_; } 101 timestamp()102 base::TimeDelta timestamp() const { return timestamp_; } duration()103 base::TimeDelta duration() const { return duration_; } set_timestamp(base::TimeDelta timestamp)104 void set_timestamp(base::TimeDelta timestamp) { timestamp_ = timestamp; } 105 106 // If there's no data in this buffer, it represents end of stream. end_of_stream()107 bool end_of_stream() const { return end_of_stream_; } 108 109 // Access to the raw buffer for ffmpeg to write directly to. Data for planar 110 // data is grouped by channel. There is only 1 entry for interleaved formats. channel_data()111 const std::vector<uint8*>& channel_data() const { return channel_data_; } 112 113 private: 114 friend class base::RefCountedThreadSafe<AudioBuffer>; 115 116 // Allocates aligned contiguous buffer to hold all channel data (1 block for 117 // interleaved data, |channel_count| blocks for planar data), copies 118 // [data,data+data_size) to the allocated buffer(s). If |data| is null, no 119 // data is copied. If |create_buffer| is false, no data buffer is created (or 120 // copied to). 121 AudioBuffer(SampleFormat sample_format, 122 ChannelLayout channel_layout, 123 int channel_count, 124 int sample_rate, 125 int frame_count, 126 bool create_buffer, 127 const uint8* const* data, 128 const base::TimeDelta timestamp); 129 130 virtual ~AudioBuffer(); 131 132 const SampleFormat sample_format_; 133 const ChannelLayout channel_layout_; 134 const int channel_count_; 135 const int sample_rate_; 136 int adjusted_frame_count_; 137 int trim_start_; 138 const bool end_of_stream_; 139 base::TimeDelta timestamp_; 140 base::TimeDelta duration_; 141 142 // Contiguous block of channel data. 143 scoped_ptr<uint8, base::AlignedFreeDeleter> data_; 144 145 // For planar data, points to each channels data. 146 std::vector<uint8*> channel_data_; 147 148 DISALLOW_IMPLICIT_CONSTRUCTORS(AudioBuffer); 149 }; 150 151 } // namespace media 152 153 #endif // MEDIA_BASE_AUDIO_BUFFER_H_ 154