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/media_export.h" 15 #include "media/base/sample_format.h" 16 17 namespace media { 18 class AudioBus; 19 20 // An audio buffer that takes a copy of the data passed to it, holds it, and 21 // copies it into an AudioBus when needed. Also supports an end of stream 22 // marker. 23 class MEDIA_EXPORT AudioBuffer 24 : public base::RefCountedThreadSafe<AudioBuffer> { 25 public: 26 // Alignment of each channel's data; this must match what ffmpeg expects 27 // (which may be 0, 16, or 32, depending on the processor). Selecting 32 in 28 // order to work on all processors. 29 enum { kChannelAlignment = 32 }; 30 31 // Create an AudioBuffer whose channel data is copied from |data|. For 32 // interleaved data, only the first buffer is used. For planar data, the 33 // number of buffers must be equal to |channel_count|. |frame_count| is the 34 // number of frames in each buffer. |data| must not be null and |frame_count| 35 // must be >= 0. 36 // 37 // TODO(jrummell): Compute duration rather than pass it in. 38 static scoped_refptr<AudioBuffer> CopyFrom(SampleFormat sample_format, 39 int channel_count, 40 int frame_count, 41 const uint8* const* data, 42 const base::TimeDelta timestamp, 43 const base::TimeDelta duration); 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 int channel_count, 49 int frame_count); 50 51 // Create an empty AudioBuffer with |frame_count| frames. 52 static scoped_refptr<AudioBuffer> CreateEmptyBuffer( 53 int channel_count, 54 int frame_count, 55 const base::TimeDelta timestamp, 56 const base::TimeDelta duration); 57 58 // Create a AudioBuffer indicating we've reached end of stream. 59 // Calling any method other than end_of_stream() on the resulting buffer 60 // is disallowed. 61 static scoped_refptr<AudioBuffer> CreateEOSBuffer(); 62 63 // Copy frames into |dest|. |frames_to_copy| is the number of frames to copy. 64 // |source_frame_offset| specifies how many frames in the buffer to skip 65 // first. |dest_frame_offset| is the frame offset in |dest|. The frames are 66 // converted from their source format into planar float32 data (which is all 67 // that AudioBus handles). 68 void ReadFrames(int frames_to_copy, 69 int source_frame_offset, 70 int dest_frame_offset, 71 AudioBus* dest); 72 73 // Trim an AudioBuffer by removing |frames_to_trim| frames from the start. 74 // Timestamp and duration are adjusted to reflect the fewer frames. 75 // Note that repeated calls to TrimStart() may result in timestamp() and 76 // duration() being off by a few microseconds due to rounding issues. 77 void TrimStart(int frames_to_trim); 78 79 // Trim an AudioBuffer by removing |frames_to_trim| frames from the end. 80 // Duration is adjusted to reflect the fewer frames. 81 void TrimEnd(int frames_to_trim); 82 83 // Return the number of channels. 84 int channel_count() const { return channel_count_; } 85 86 // Return the number of frames held. 87 int frame_count() const { return adjusted_frame_count_; } 88 89 // Access to constructor parameters. 90 base::TimeDelta timestamp() const { return timestamp_; } 91 base::TimeDelta duration() const { return duration_; } 92 93 // TODO(jrummell): Remove set_timestamp() and set_duration() once 94 // DecryptingAudioDecoder::EnqueueFrames() is changed to set them when 95 // creating the buffer. See http://crbug.com/255261. 96 void set_timestamp(base::TimeDelta timestamp) { timestamp_ = timestamp; } 97 void set_duration(base::TimeDelta duration) { duration_ = duration; } 98 99 // If there's no data in this buffer, it represents end of stream. 100 bool end_of_stream() const { return end_of_stream_; } 101 102 // Access to the raw buffer for ffmpeg to write directly to. Data for planar 103 // data is grouped by channel. There is only 1 entry for interleaved formats. 104 const std::vector<uint8*>& channel_data() const { return channel_data_; } 105 106 private: 107 friend class base::RefCountedThreadSafe<AudioBuffer>; 108 109 // Allocates aligned contiguous buffer to hold all channel data (1 block for 110 // interleaved data, |channel_count| blocks for planar data), copies 111 // [data,data+data_size) to the allocated buffer(s). If |data| is null, no 112 // data is copied. If |create_buffer| is false, no data buffer is created (or 113 // copied to). 114 AudioBuffer(SampleFormat sample_format, 115 int channel_count, 116 int frame_count, 117 bool create_buffer, 118 const uint8* const* data, 119 const base::TimeDelta timestamp, 120 const base::TimeDelta duration); 121 122 virtual ~AudioBuffer(); 123 124 const SampleFormat sample_format_; 125 const int channel_count_; 126 int adjusted_frame_count_; 127 int trim_start_; 128 const bool end_of_stream_; 129 base::TimeDelta timestamp_; 130 base::TimeDelta duration_; 131 132 // Contiguous block of channel data. 133 scoped_ptr_malloc<uint8, base::ScopedPtrAlignedFree> data_; 134 135 // For planar data, points to each channels data. 136 std::vector<uint8*> channel_data_; 137 138 DISALLOW_IMPLICIT_CONSTRUCTORS(AudioBuffer); 139 }; 140 141 } // namespace media 142 143 #endif // MEDIA_BASE_AUDIO_BUFFER_H_ 144
