67 lines
1.5 KiB
C++
67 lines
1.5 KiB
C++
// SPDX-License-Identifier: GPL-2.0-or-later
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// Copyright The Music Player Daemon Project
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#ifndef MPD_PCM_RESAMPLER_HXX
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#define MPD_PCM_RESAMPLER_HXX
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#include <cstddef>
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#include <span>
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struct AudioFormat;
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/**
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* This is an interface for plugins that convert PCM data to a
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* specific sample rate.
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*/
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class PcmResampler {
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public:
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virtual ~PcmResampler() = default;
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/**
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* Opens the resampler, preparing it for Resample().
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*
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* Throws std::runtime_error on error.
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*
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* @param af the audio format of incoming data; the plugin may
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* modify the object to enforce another input format (however,
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* it may not request a different input sample rate)
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* @param new_sample_rate the requested output sample rate
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* @return the format of outgoing data
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*/
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virtual AudioFormat Open(AudioFormat &af,
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unsigned new_sample_rate) = 0;
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/**
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* Closes the resampler. After that, you may call Open()
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* again.
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*/
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virtual void Close() noexcept = 0;
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/**
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* Reset the filter's state, e.g. drop/flush buffers.
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*/
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virtual void Reset() noexcept {
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}
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/**
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* Resamples a block of PCM data.
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*
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* Throws std::runtime_error on error.
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*
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* @param src the input buffer
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* @return the destination buffer (will be invalidated by
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* filter_close() or filter_filter())
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*/
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virtual std::span<const std::byte> Resample(std::span<const std::byte> src) = 0;
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/**
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* Flush pending data and return it. This should be called
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* repepatedly until it returns nullptr.
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*/
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virtual std::span<const std::byte> Flush() {
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return {};
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}
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};
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#endif
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