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80 lines
2.0 KiB
C++
80 lines
2.0 KiB
C++
// SPDX-License-Identifier: GPL-2.0-or-later
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// Copyright The Music Player Daemon Project
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#include "Dop.hxx"
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#include "ChannelDefs.hxx"
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#include <cassert>
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#include <functional>
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static constexpr uint32_t
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pcm_two_dsd_to_dop_marker1(std::byte a, std::byte b) noexcept
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{
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return 0xff050000 | (static_cast<uint32_t>(a) << 8) | static_cast<uint32_t>(b);
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}
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static constexpr uint32_t
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pcm_two_dsd_to_dop_marker2(std::byte a, std::byte b) noexcept
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{
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return 0xfffa0000 | (static_cast<uint32_t>(a) << 8) | static_cast<uint32_t>(b);
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}
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/**
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* @param num_dop_quads the number of "quad" bytes per channel in the
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* source buffer; each "quad" will be converted to two 24 bit samples
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* in the destination buffer, one for each marker
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*/
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static void
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DsdToDop(uint32_t *dest, const std::byte *src,
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size_t num_dop_quads, unsigned channels) noexcept
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{
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for (size_t i = num_dop_quads; i > 0; --i) {
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for (unsigned c = channels; c > 0; --c) {
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/* each 24 bit sample has 16 DSD sample bits
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plus the magic 0x05 marker */
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*dest++ = pcm_two_dsd_to_dop_marker1(src[0], src[channels]);
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/* seek the source pointer to the next
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channel */
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++src;
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}
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/* skip the second byte of each channel, because we
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have already copied it */
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src += channels;
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for (unsigned c = channels; c > 0; --c) {
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/* each 24 bit sample has 16 DSD sample bits
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plus the magic 0xfa marker */
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*dest++ = pcm_two_dsd_to_dop_marker2(src[0], src[channels]);
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/* seek the source pointer to the next
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channel */
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++src;
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}
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/* skip the second byte of each channel, because we
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have already copied it */
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src += channels;
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}
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}
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void
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DsdToDopConverter::Open(unsigned _channels) noexcept
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{
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assert(audio_valid_channel_count(_channels));
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channels = _channels;
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rest_buffer.Open(channels);
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}
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std::span<const uint32_t>
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DsdToDopConverter::Convert(std::span<const std::byte> src) noexcept
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{
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return rest_buffer.Process<uint32_t>(buffer, src, 2 * channels,
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[this](auto && arg1, auto && arg2, auto && arg3) { return DsdToDop(arg1, arg2, arg3, channels); });
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}
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