dolphin/Source/Core/AudioCommon/SurroundDecoder.cpp

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// Copyright 2017 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
2021-12-10 02:22:16 +00:00
#include "AudioCommon/SurroundDecoder.h"
#include <FreeSurround/FreeSurroundDecoder.h>
#include <limits>
namespace AudioCommon
{
constexpr size_t STEREO_CHANNELS = 2;
constexpr size_t SURROUND_CHANNELS = 6;
SurroundDecoder::SurroundDecoder(u32 sample_rate, u32 frame_block_size)
: m_sample_rate(sample_rate), m_frame_block_size(frame_block_size)
{
m_fsdecoder = std::make_unique<DPL2FSDecoder>();
m_fsdecoder->Init(cs_5point1, m_frame_block_size, m_sample_rate);
}
SurroundDecoder::~SurroundDecoder() = default;
void SurroundDecoder::Clear()
{
m_fsdecoder->flush();
m_decoded_fifo.clear();
}
// Currently only 6 channels are supported.
size_t SurroundDecoder::QueryFramesNeededForSurroundOutput(const size_t output_frames) const
{
if (m_decoded_fifo.size() < output_frames * SURROUND_CHANNELS)
{
// Output stereo frames needed to have at least the desired number of surround frames
size_t frames_needed = output_frames - m_decoded_fifo.size() / SURROUND_CHANNELS;
return frames_needed + m_frame_block_size - frames_needed % m_frame_block_size;
}
return 0;
}
// Receive and decode samples
void SurroundDecoder::PutFrames(const short* in, const size_t num_frames_in)
{
// Maybe check if it is really power-of-2?
s64 remaining_frames = static_cast<s64>(num_frames_in);
size_t frame_index = 0;
while (remaining_frames > 0)
{
// Convert to float
for (size_t i = 0, end = m_frame_block_size * STEREO_CHANNELS; i < end; ++i)
{
m_float_conversion_buffer[i] = in[i + frame_index * STEREO_CHANNELS] /
static_cast<float>(std::numeric_limits<short>::max());
}
// Decode
const float* dpl2_fs = m_fsdecoder->decode(m_float_conversion_buffer.data());
// Add to ring buffer and fix channel mapping
// Maybe modify FreeSurround to output the correct mapping?
// FreeSurround:
// FL | FC | FR | BL | BR | LFE
// Most backends:
// FL | FR | FC | LFE | BL | BR
for (size_t i = 0; i < m_frame_block_size; ++i)
{
m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 0]); // LEFTFRONT
m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 2]); // RIGHTFRONT
m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 1]); // CENTREFRONT
m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 5]); // sub/lfe
m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 3]); // LEFTREAR
m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 4]); // RIGHTREAR
}
remaining_frames = remaining_frames - static_cast<int>(m_frame_block_size);
frame_index = frame_index + m_frame_block_size;
}
}
void SurroundDecoder::ReceiveFrames(float* out, const size_t num_frames_out)
{
// Copy to output array with desired num_frames_out
for (size_t i = 0, num_samples_output = num_frames_out * SURROUND_CHANNELS;
i < num_samples_output; ++i)
{
out[i] = m_decoded_fifo.pop_front();
}
}
} // namespace AudioCommon