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// Copyright 2015 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 PPAPI_CPP_AUDIO_ENCODER_H_
#define PPAPI_CPP_AUDIO_ENCODER_H_
#include <stdint.h>
#include "ppapi/c/pp_codecs.h"
#include "ppapi/c/ppb_audio_buffer.h"
#include "ppapi/cpp/audio_buffer.h"
#include "ppapi/cpp/completion_callback.h"
#include "ppapi/cpp/resource.h"
/// @file
/// This file defines the API to create and use a AudioEncoder resource.
namespace pp {
class InstanceHandle;
/// Audio encoder interface.
///
/// Typical usage:
/// - Call Create() to create a new audio encoder resource.
/// - Call GetSupportedFormats() to determine which codecs and profiles are
/// available.
/// - Call Initialize() to initialize the encoder for a supported profile.
/// - Call GetBuffer() to get a blank frame and fill it in, or get an audio
/// frame from another resource, e.g. <code>PPB_MediaStreamAudioTrack</code>.
/// - Call Encode() to push the audio buffer to the encoder. If an external
/// buffer is pushed, wait for completion to recycle the frame.
/// - Call GetBitstreamBuffer() continuously (waiting for each previous call to
/// complete) to pull encoded buffers from the encoder.
/// - Call RecycleBitstreamBuffer() after consuming the data in the bitstream
/// buffer.
/// - To destroy the encoder, the plugin should release all of its references to
/// it. Any pending callbacks will abort before the encoder is destroyed.
///
/// Available audio codecs vary by platform.
/// All: opus.
class AudioEncoder : public Resource {
public:
/// Default constructor for creating an is_null() <code>AudioEncoder</code>
/// object.
AudioEncoder();
/// A constructor used to create a <code>AudioEncoder</code> and associate it
/// with the provided <code>Instance</code>.
/// @param[in] instance The instance with which this resource will be
/// associated.
explicit AudioEncoder(const InstanceHandle& instance);
/// The copy constructor for <code>AudioEncoder</code>.
/// @param[in] other A reference to a <code>AudioEncoder</code>.
AudioEncoder(const AudioEncoder& other);
/// Gets an array of supported audio encoder profiles.
/// These can be used to choose a profile before calling Initialize().
///
/// @param[in] callback A <code>CompletionCallbackWithOutput</code> to be
/// called upon completion with the PP_AudioProfileDescription structs.
///
/// @return If >= 0, the number of supported profiles returned, otherwise an
/// error code from <code>pp_errors.h</code>.
int32_t GetSupportedProfiles(const CompletionCallbackWithOutput<
std::vector<PP_AudioProfileDescription> >& cc);
/// Initializes a audio encoder resource. This should be called after
/// GetSupportedProfiles() and before any functions below.
///
/// @param[in] channels The number of audio channels to encode.
/// @param[in] input_sampling_rate The sampling rate of the input audio
/// buffer.
/// @param[in] input_sample_size The sample size of the input audio buffer.
/// @param[in] output_profile A <code>PP_AudioProfile</code> specifying the
/// codec profile of the encoded output stream.
/// @param[in] initial_bitrate The initial bitrate for the encoder.
/// @param[in] acceleration A <code>PP_HardwareAcceleration</code> specifying
/// whether to use a hardware accelerated or a software implementation.
/// @param[in] callback A <code>CompletionCallback</code> to be called upon
/// completion.
///
/// @return An int32_t containing an error code from <code>pp_errors.h</code>.
/// Returns PP_ERROR_NOTSUPPORTED if audio encoding is not available, or the
/// requested codec profile is not supported.
/// Returns PP_ERROR_NOMEMORY if bitstream buffers can't be created.
int32_t Initialize(uint32_t channels,
PP_AudioBuffer_SampleRate input_sample_rate,
PP_AudioBuffer_SampleSize input_sample_size,
PP_AudioProfile output_profile,
uint32_t initial_bitrate,
PP_HardwareAcceleration acceleration,
const CompletionCallback& cc);
/// Gets the number of audio samples per channel that audio buffers
/// must contain in order to be processed by the encoder. This will
/// be the number of samples per channels contained in buffers
/// returned by GetBuffer().
///
/// @return An int32_t containing the number of samples required, or an error
/// code from <code>pp_errors.h</code>.
/// Returns PP_ERROR_FAILED if Initialize() has not successfully completed.
int32_t GetNumberOfSamples();
/// Gets a blank audio frame which can be filled with audio data and passed
/// to the encoder.
///
/// @param[in] callback A <code>CompletionCallbackWithOutput</code> to be
/// called upon completion with the blank <code>AudioBuffer</code> resource.
///
/// @return An int32_t containing an error code from <code>pp_errors.h</code>.
int32_t GetBuffer(const CompletionCallbackWithOutput<AudioBuffer>& cc);
/// Encodes an audio buffer.
///
/// @param[in] audio_buffer The <code>AudioBuffer</code> to be encoded.
/// @param[in] callback A <code>CompletionCallback</code> to be called upon
/// completion. Plugins that pass <code>AudioBuffer</code> resources owned
/// by other resources should wait for completion before reusing them.
///
/// @return An int32_t containing an error code from <code>pp_errors.h</code>.
/// Returns PP_ERROR_FAILED if Initialize() has not successfully completed.
int32_t Encode(const AudioBuffer& buffer, const CompletionCallback& cc);
/// Gets the next encoded bitstream buffer from the encoder.
///
/// @param[in] callback A <code>CompletionCallbackWithOutput</code> to be
/// called upon completion with the next bitstream buffer. The plugin can call
/// GetBitstreamBuffer from the callback in order to continuously "pull"
/// bitstream buffers from the encoder.
///
/// @return An int32_t containing an error code from <code>pp_errors.h</code>.
/// Returns PP_ERROR_FAILED if Initialize() has not successfully completed.
/// Returns PP_ERROR_INPROGRESS if a prior call to GetBitstreamBuffer() has
/// not completed.
int32_t GetBitstreamBuffer(
const CompletionCallbackWithOutput<PP_AudioBitstreamBuffer>& cc);
/// Recycles a bitstream buffer back to the encoder.
///
/// @param[in] bitstream_buffer A<code>PP_AudioBitstreamBuffer</code> that
/// is no longer needed by the plugin.
void RecycleBitstreamBuffer(const PP_AudioBitstreamBuffer& bitstream_buffer);
/// Requests a change to the encoding bitrate. This is only a request,
/// fulfilled on a best-effort basis.
///
/// @param[in] audio_encoder A <code>PP_Resource</code> identifying the audio
/// encoder.
void RequestBitrateChange(uint32_t bitrate);
/// Closes the audio encoder, and cancels any pending encodes. Any pending
/// callbacks will still run, reporting <code>PP_ERROR_ABORTED</code> . It is
/// not valid to call any encoder functions after a call to this method.
/// <strong>Note:</strong> Destroying the audio encoder closes it implicitly,
/// so you are not required to call Close().
void Close();
};
} // namespace pp
#endif // PPAPI_CPP_AUDIO_ENCODER_H_
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