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0b421a3764
Brought to you by the inventor of QOI, QOA is a lossy audio codec that is, as the name says, quite okay in compressing audio data reasonably well without frequency transformation, mostly introducing some white noise in the background. This implementation of QOA is fully compatible with the qoa.h reference implementation as of 2023-02-25. Note that there may be changes to the QOA format before a specification is finalized, and there is currently no information on when that will happen and which changes will be made. This implementation of QOA can handle varying sample rate and varying channel count files. The reference implementation does not produce these files and cannot handle them, so their implementation is untested. The QOA loader is capable of seeking in constant-bitrate streams. QOA links: https://phoboslab.org/log/2023/02/qoa-time-domain-audio-compression https://github.com/phoboslab/qoa
69 lines
2.6 KiB
C++
69 lines
2.6 KiB
C++
/*
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* Copyright (c) 2023, kleines Filmröllchen <filmroellchen@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Error.h>
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#include <AK/Span.h>
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#include <AK/Types.h>
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#include <LibAudio/Loader.h>
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#include <LibAudio/QOATypes.h>
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#include <LibAudio/SampleFormats.h>
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namespace Audio {
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// Decoder for the Quite Okay Audio (QOA) format.
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// NOTE: The QOA format is not finalized yet and this decoder might not be fully spec-compliant as of 2023-02-02.
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//
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// https://github.com/phoboslab/qoa/blob/master/qoa.h
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class QOALoaderPlugin : public LoaderPlugin {
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public:
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explicit QOALoaderPlugin(NonnullOwnPtr<AK::SeekableStream> stream);
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virtual ~QOALoaderPlugin() override = default;
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static Result<NonnullOwnPtr<QOALoaderPlugin>, LoaderError> create(StringView path);
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static Result<NonnullOwnPtr<QOALoaderPlugin>, LoaderError> create(Bytes buffer);
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virtual LoaderSamples get_more_samples(size_t max_samples_to_read_from_input = 128 * KiB) override;
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virtual MaybeLoaderError reset() override;
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virtual MaybeLoaderError seek(int sample_index) override;
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virtual int loaded_samples() override { return static_cast<int>(m_loaded_samples); }
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virtual int total_samples() override { return static_cast<int>(m_total_samples); }
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virtual u32 sample_rate() override { return m_sample_rate; }
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virtual u16 num_channels() override { return m_num_channels; }
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virtual DeprecatedString format_name() override { return "Quite Okay Audio (.qoa)"; }
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virtual PcmSampleFormat pcm_format() override { return PcmSampleFormat::Int16; }
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private:
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enum class IsFirstFrame : bool {
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Yes = true,
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No = false,
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};
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MaybeLoaderError initialize();
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MaybeLoaderError parse_header();
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MaybeLoaderError load_one_frame(Span<Sample>& target, IsFirstFrame is_first_frame = IsFirstFrame::No);
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// Updates predictor values in lms_state so the next slice can reuse the same state.
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MaybeLoaderError read_one_slice(QOA::LMSState& lms_state, Span<i16>& samples);
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static ALWAYS_INLINE QOA::UnpackedSlice unpack_slice(QOA::PackedSlice packed_slice);
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// QOA's division routine for scaling residuals before final quantization.
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static ALWAYS_INLINE i16 qoa_divide(i16 value, i16 scale_factor);
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// Because QOA has dynamic sample rate and channel count, we only use the sample rate and channel count from the first frame.
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u32 m_sample_rate { 0 };
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u8 m_num_channels { 0 };
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// If this is the case (the reference encoder even enforces it at the moment)
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bool m_has_uniform_channel_count { true };
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size_t m_loaded_samples { 0 };
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size_t m_total_samples { 0 };
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};
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}
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