media/base/audio_buffer.h

   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.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   // Create an AudioBuffer whose channel data is copied from |data|. For
  27   // interleaved data, only the first buffer is used. For planar data, the
  28   // number of buffers must be equal to |channel_count|. |frame_count| is the
  29   // number of frames in each buffer. |data| must not be null and |frame_count|
  30   // must be >= 0.
  31   //
  32   // TODO(jrummell): Compute duration rather than pass it in.
  33   static scoped_refptr<AudioBuffer> CopyFrom(SampleFormat sample_format,
  34                                              int channel_count,
  35                                              int frame_count,
  36                                              const uint8* const* data,
  37                                              const base::TimeDelta timestamp,
  38                                              const base::TimeDelta duration);
  39
  40   // Create a AudioBuffer indicating we've reached end of stream.
  41   // Calling any method other than end_of_stream() on the resulting buffer
  42   // is disallowed.
  43   static scoped_refptr<AudioBuffer> CreateEOSBuffer();
  44
  45   // Copy frames into |dest|. |frames_to_copy| is the number of frames to copy.
  46   // |source_frame_offset| specified how many frames in the buffer to skip
  47   // first. |dest_frame_offset| is the frame offset in |dest|. The frames are
  48   // converted from their source format into planar float32 data (which is all
  49   // that AudioBus handles).
  50   void ReadFrames(int frames_to_copy,
  51                   int source_frame_offset,
  52                   int dest_frame_offset,
  53                   AudioBus* dest);
  54
  55   // Return the number of frames held.
  56   int frame_count() const { return frame_count_; }
  57
  58   // Access to constructor parameters.
  59   base::TimeDelta timestamp() const { return timestamp_; }
  60   base::TimeDelta duration() const { return duration_; }
  61
  62   // If there's no data in this buffer, it represents end of stream.
  63   bool end_of_stream() const { return data_ == NULL; }
  64
  65  private:
  66   friend class base::RefCountedThreadSafe<AudioBuffer>;
  67
  68   // Allocates aligned contiguous buffer to hold all channel data (1 block for
  69   // interleaved data, |channel_count| blocks for planar data), copies
  70   // [data,data+data_size) to the allocated buffer(s). If |data| is null an end
  71   // of stream buffer is created.
  72   AudioBuffer(SampleFormat sample_format,
  73               int channel_count,
  74               int frame_count,
  75               const uint8* const* data,
  76               const base::TimeDelta timestamp,
  77               const base::TimeDelta duration);
  78
  79   virtual ~AudioBuffer();
  80
  81   SampleFormat sample_format_;
  82   int channel_count_;
  83   int frame_count_;
  84   base::TimeDelta timestamp_;
  85   base::TimeDelta duration_;
  86
  87   // Contiguous block of channel data.
  88   scoped_ptr_malloc<uint8, base::ScopedPtrAlignedFree> data_;
  89
  90   // For planar data, points to each channels data.
  91   std::vector<uint8*> channel_data_;
  92
  93   DISALLOW_IMPLICIT_CONSTRUCTORS(AudioBuffer);
  94 };
  95
  96 }  // namespace media
  97
  98 #endif  // MEDIA_BASE_AUDIO_BUFFER_H_