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/*
* Copyright (c) 2021, kleines Filmröllchen <filmroellchen@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include "Queue.h"
#include "SampleFormats.h"
#include <AK/ByteBuffer.h>
#include <AK/Types.h>
#include <AK/Variant.h>
#include <LibCrypto/Checksum/CRC8.h>
namespace Audio {
// These are not the actual values stored in the file! They are marker constants instead, only used temporarily in the decoder.
// 11.22.3. INTERCHANNEL SAMPLE BLOCK SIZE
#define FLAC_BLOCKSIZE_AT_END_OF_HEADER_8 0xffffffff
#define FLAC_BLOCKSIZE_AT_END_OF_HEADER_16 0xfffffffe
// 11.22.4. SAMPLE RATE
#define FLAC_SAMPLERATE_AT_END_OF_HEADER_8 0xffffffff
#define FLAC_SAMPLERATE_AT_END_OF_HEADER_16 0xfffffffe
#define FLAC_SAMPLERATE_AT_END_OF_HEADER_16X10 0xfffffffd
// 11.22.11. FRAME CRC
// The polynomial used here is known as CRC-8-CCITT.
static constexpr u8 flac_polynomial = 0x07;
using FlacFrameHeaderCRC = Crypto::Checksum::CRC8<flac_polynomial>;
// 11.8 BLOCK_TYPE (7 bits)
enum class FlacMetadataBlockType : u8 {
STREAMINFO = 0, // Important data about the audio format
PADDING = 1, // Non-data block to be ignored
APPLICATION = 2, // Ignored
SEEKTABLE = 3, // Seeking info, maybe to be used later
VORBIS_COMMENT = 4, // Ignored
CUESHEET = 5, // Ignored
PICTURE = 6, // Ignored
INVALID = 127, // Error
};
// 11.22.5. CHANNEL ASSIGNMENT
enum class FlacFrameChannelType : u8 {
Mono = 0,
Stereo = 1,
StereoCenter = 2, // left, right, center
Surround4p0 = 3, // front left/right, back left/right
Surround5p0 = 4, // front left/right, center, back left/right
Surround5p1 = 5, // front left/right, center, LFE, back left/right
Surround6p1 = 6, // front left/right, center, LFE, back center, side left/right
Surround7p1 = 7, // front left/right, center, LFE, back left/right, side left/right
LeftSideStereo = 8, // channel coupling: left and difference
RightSideStereo = 9, // channel coupling: difference and right
MidSideStereo = 10, // channel coupling: center and difference
// others are reserved
};
// 11.25.1. SUBFRAME TYPE
enum class FlacSubframeType : u8 {
Constant = 0,
Verbatim = 1,
Fixed = 0b001000,
LPC = 0b100000,
// others are reserved
};
// 11.30.1. RESIDUAL_CODING_METHOD
enum class FlacResidualMode : u8 {
Rice4Bit = 0,
Rice5Bit = 1,
};
// 11.6. METADATA_BLOCK
struct FlacRawMetadataBlock {
bool is_last_block;
FlacMetadataBlockType type;
u32 length; // 24 bits
ByteBuffer data;
};
// 11.22. FRAME_HEADER
struct FlacFrameHeader {
u32 sample_count;
u32 sample_rate;
FlacFrameChannelType channels;
u8 bit_depth;
u8 checksum;
};
// 11.25. SUBFRAME_HEADER
struct FlacSubframeHeader {
FlacSubframeType type;
// order for fixed and LPC subframes
u8 order;
u8 wasted_bits_per_sample;
u8 bits_per_sample;
};
}
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