diff options
Diffstat (limited to 'chromium/media/base/audio_buffer_converter.h')
-rw-r--r-- | chromium/media/base/audio_buffer_converter.h | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/chromium/media/base/audio_buffer_converter.h b/chromium/media/base/audio_buffer_converter.h new file mode 100644 index 00000000000..9efbd16a233 --- /dev/null +++ b/chromium/media/base/audio_buffer_converter.h @@ -0,0 +1,108 @@ +// Copyright 2014 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +#ifndef MEDIA_BASE_AUDIO_BUFFER_CONVERTER +#define MEDIA_BASE_AUDIO_BUFFER_CONVERTER + +#include <deque> + +#include "base/memory/ref_counted.h" +#include "base/memory/scoped_ptr.h" +#include "base/time/time.h" +#include "media/audio/audio_parameters.h" +#include "media/base/audio_converter.h" +#include "media/base/audio_timestamp_helper.h" +#include "media/base/media_export.h" + +namespace media { + +class AudioBuffer; +class AudioBus; + +// Takes AudioBuffers in any format and uses an AudioConverter to convert them +// to a common format (usually the hardware output format). +class MEDIA_EXPORT AudioBufferConverter : public AudioConverter::InputCallback { + public: + explicit AudioBufferConverter(const AudioParameters& output_params); + virtual ~AudioBufferConverter(); + + void AddInput(const scoped_refptr<AudioBuffer>& buffer); + + // Is an output buffer available via GetNextBuffer()? + bool HasNextBuffer(); + + // This should only be called this is HasNextBuffer() returns true. + scoped_refptr<AudioBuffer> GetNextBuffer(); + + // Reset internal state. + void Reset(); + + // Reset internal timestamp state. Upon the next AddInput() call, our base + // timestamp will be set to match the input buffer. + void ResetTimestampState(); + + int input_buffer_size_for_testing() const { + return input_params_.frames_per_buffer(); + } + int input_frames_left_for_testing() const { + return input_frames_; + } + + private: + // Callback to provide data to the AudioConverter + virtual double ProvideInput(AudioBus* audio_bus, + base::TimeDelta buffer_delay) OVERRIDE; + + // Reset the converter in response to a configuration change. + void ResetConverter(const scoped_refptr<AudioBuffer>& input_buffer); + + // Perform conversion if we have enough data. + void ConvertIfPossible(); + + // Flush remaining output + void Flush(); + + // The output parameters. + AudioParameters output_params_; + + // The current input parameters (we cache these to detect configuration + // changes, so we know when to reset the AudioConverter). + AudioParameters input_params_; + + typedef std::deque<scoped_refptr<AudioBuffer> > BufferQueue; + + // Queued up inputs (there will never be all that much data stored here, as + // soon as there's enough here to produce an output buffer we will do so). + BufferQueue queued_inputs_; + + // Offset into the front element of |queued_inputs_|. A ProvideInput() call + // doesn't necessarily always consume an entire buffer. + int last_input_buffer_offset_; + + // Buffer of output frames, to be returned by GetNextBuffer(). + BufferQueue queued_outputs_; + + // How many frames of input we have in |queued_inputs_|. + int input_frames_; + + // Input frames in the AudioConverter's internal buffers. + double buffered_input_frames_; + + // Ratio of sample rates, in/out. + double io_sample_rate_ratio_; + + // Computes timestamps in terms of the output sample rate. + AudioTimestampHelper timestamp_helper_; + + // Are we flushing everything, without regard for providing AudioConverter + // full AudioBuses in ProvideInput()? + bool is_flushing_; + + // The AudioConverter which does the real work here. + scoped_ptr<AudioConverter> audio_converter_; +}; + +} // namespace media + +#endif // MEDIA_BASE_AUDIO_BUFFER_CONVERTER |