RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-27 09:07:45 +00:00
Code Issues Activity Actions

LibAudio: Add basic MP3 Decoder

Browse source 
This is a basic MPEG-1 layer 3 audio decoder. It supports all
sample rates and stereo modes except for freeformat.
This commit is contained in:
Arne Elster 2022-02-24 11:27:48 +01:00 • committed by Andreas Kling
parent 6a64aabce8
commit 7223b593cb
5 changed files with 1106 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

81
Userland/Libraries/LibAudio/MP3Loader.h Normal file
View file

@ -0,0 +1,81 @@
/*
* Copyright (c) 2021, Arne Elster <arne@elster.li>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include "Buffer.h"
#include "Loader.h"
#include "MP3Types.h"
#include <AK/Tuple.h>
#include <LibCore/FileStream.h>
#include <LibDSP/MDCT.h>
namespace Audio {
namespace MP3::Tables {
struct ScaleFactorBand;
}
class MP3LoaderPlugin : public LoaderPlugin {
public:
explicit MP3LoaderPlugin(StringView path);
~MP3LoaderPlugin();
virtual MaybeLoaderError initialize() override;
virtual LoaderSamples get_more_samples(size_t max_bytes_to_read_from_input = 128 * KiB) override;
virtual MaybeLoaderError reset() override;
virtual MaybeLoaderError seek(int const position) override;
virtual int loaded_samples() override { return m_loaded_samples; }
virtual int total_samples() override { return m_total_samples; }
virtual u32 sample_rate() override { return m_sample_rate; }
virtual u16 num_channels() override { return m_num_channels; }
virtual PcmSampleFormat pcm_format() override { return m_sample_format; }
virtual RefPtr<Core::File> file() override { return m_file; }
virtual String format_name() override { return "MP3 (.mp3)"; }
private:
MaybeLoaderError synchronize();
MaybeLoaderError build_seek_table();
ErrorOr<MP3::Header, LoaderError> read_header();
ErrorOr<MP3::MP3Frame, LoaderError> read_next_frame();
ErrorOr<MP3::MP3Frame, LoaderError> read_frame_data(MP3::Header const&, bool is_first_frame);
MaybeLoaderError read_side_information(MP3::MP3Frame&);
ErrorOr<size_t, LoaderError> read_scale_factors(MP3::MP3Frame&, InputBitStream& reservoir, size_t granule_index, size_t channel_index);
MaybeLoaderError read_huffman_data(MP3::MP3Frame&, InputBitStream& reservoir, size_t granule_index, size_t channel_index, size_t granule_bits_read);
static AK::Array<double, 576> calculate_frame_exponents(MP3::MP3Frame const&, size_t granule_index, size_t channel_index);
static void reorder_samples(MP3::Granule&, u32 sample_rate);
static void reduce_alias(MP3::Granule&, size_t max_subband_index = 576);
static void process_stereo(MP3::MP3Frame&, size_t granule_index);
static void transform_samples_to_time(Array<double, 576> const& input, size_t input_offset, Array<double, 36>& output, MP3::BlockType block_type);
static void synthesis(Array<double, 1024>& V, Array<double, 32>& samples, Array<double, 32>& result);
static Span<MP3::Tables::ScaleFactorBand const> get_scalefactor_bands(MP3::Granule const&, int samplerate);
AK::Vector<AK::Tuple<size_t, int>> m_seek_table;
AK::Array<AK::Array<AK::Array<double, 18>, 32>, 2> m_last_values {};
AK::Array<AK::Array<double, 1024>, 2> m_synthesis_buffer {};
static LibDSP::MDCT<36> s_mdct_36;
static LibDSP::MDCT<12> s_mdct_12;
u32 m_sample_rate { 0 };
u8 m_num_channels { 0 };
PcmSampleFormat m_sample_format { PcmSampleFormat::Int16 };
size_t m_file_size { 0 };
int m_total_samples { 0 };
size_t m_loaded_samples { 0 };
bool m_is_first_frame { true };
AK::Optional<MP3::MP3Frame> m_current_frame;
u32 m_current_frame_read;
RefPtr<Core::File> m_file;
OwnPtr<Core::InputFileStream> m_input_stream;
OwnPtr<InputBitStream> m_bitstream;
DuplexMemoryStream m_bit_reservoir;
Optional<LoaderError> m_error {};
};
}