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// Copyright (c) 2012 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.
#include "remoting/codec/audio_decoder_speex.h"
#include <string>
#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "base/logging.h"
#include "base/stl_util.h"
#include "remoting/proto/audio.pb.h"
#include "third_party/speex/include/speex/speex_callbacks.h"
#include "third_party/speex/include/speex/speex_stereo.h"
namespace remoting {
namespace {
// Hosts will never generate more than 100 frames in a single packet.
const int kMaxFramesPerPacket = 100;
} // namespace
AudioDecoderSpeex::AudioDecoderSpeex() {
// Create and initialize the Speex structures.
speex_bits_.reset(new SpeexBits());
speex_bits_init(speex_bits_.get());
speex_state_ = speex_decoder_init(&speex_wb_mode);
// Create and initialize the Speex stereo state.
speex_stereo_state_ = speex_stereo_state_init();
// Create and initialize the stereo callback.
speex_callback_.reset(new SpeexCallback());
speex_callback_->callback_id = SPEEX_INBAND_STEREO;
speex_callback_->func = speex_std_stereo_request_handler;
speex_callback_->data = speex_stereo_state_;
int result;
// Turn on perceptual enhancer, which will make the audio sound better,
// at the price of further distorting the decoded samples.
int enhancer = 1;
result = speex_decoder_ctl(speex_state_, SPEEX_SET_ENH, &enhancer);
CHECK_EQ(result, 0);
// Get the frame size, so that we know the size of output when we decode
// frame by frame.
result = speex_decoder_ctl(speex_state_,
SPEEX_GET_FRAME_SIZE,
&speex_frame_size_);
CHECK_EQ(result, 0);
// Set the stereo callback, so that the Speex decoder can get the intensity
// stereo information.
result = speex_decoder_ctl(speex_state_,
SPEEX_SET_HANDLER,
speex_callback_.get());
CHECK_EQ(result, 0);
}
AudioDecoderSpeex::~AudioDecoderSpeex() {
speex_stereo_state_destroy(speex_stereo_state_);
speex_decoder_destroy(speex_state_);
speex_bits_destroy(speex_bits_.get());
}
scoped_ptr<AudioPacket> AudioDecoderSpeex::Decode(
scoped_ptr<AudioPacket> packet) {
if ((packet->encoding() != AudioPacket::ENCODING_SPEEX) ||
(packet->bytes_per_sample() != AudioPacket::BYTES_PER_SAMPLE_2) ||
(packet->sampling_rate() == AudioPacket::SAMPLING_RATE_INVALID) ||
(packet->channels() != AudioPacket::CHANNELS_STEREO)) {
LOG(WARNING) << "Received an unsupported packet.";
return scoped_ptr<AudioPacket>();
}
if (packet->data_size() > kMaxFramesPerPacket) {
LOG(WARNING) << "Received an packet with too many frames.";
return scoped_ptr<AudioPacket>();
}
// Create a new packet of decoded data.
scoped_ptr<AudioPacket> decoded_packet(new AudioPacket());
decoded_packet->set_encoding(AudioPacket::ENCODING_RAW);
decoded_packet->set_sampling_rate(packet->sampling_rate());
decoded_packet->set_bytes_per_sample(packet->bytes_per_sample());
decoded_packet->set_channels(packet->channels());
std::string* decoded_data = decoded_packet->add_data();
decoded_data->resize(packet->data_size() *
speex_frame_size_ *
packet->bytes_per_sample() *
packet->channels());
int16* samples = reinterpret_cast<int16*>(string_as_array(decoded_data));
for (int i = 0; i < packet->data_size(); ++i) {
// Read the bytes into the bits structure.
speex_bits_read_from(speex_bits_.get(),
string_as_array(packet->mutable_data(i)),
packet->data(i).size());
// Decode the frame and store it in the buffer.
int status = speex_decode_int(speex_state_, speex_bits_.get(), samples);
if (status < 0) {
LOG(ERROR) << "Error in decoding Speex data.";
return scoped_ptr<AudioPacket>();
}
// Transform mono to stereo.
speex_decode_stereo_int(samples, speex_frame_size_, speex_stereo_state_);
samples += (speex_frame_size_ * packet->channels());
}
return decoded_packet.Pass();
}
} // namespace remoting
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