mirror of
https://github.com/hajimehoshi/ebiten.git
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91 lines
2.6 KiB
Go
91 lines
2.6 KiB
Go
// Copyright 2017 The Ebiten Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// +build !js
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package mp3
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type mpeg1Layer int
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const (
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mpeg1LayerReserved mpeg1Layer = 0
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mpeg1Layer3 mpeg1Layer = 1
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mpeg1Layer2 mpeg1Layer = 2
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mpeg1Layer1 mpeg1Layer = 3
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)
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type mpeg1Mode int
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const (
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mpeg1ModeStereo mpeg1Mode = iota
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mpeg1ModeJointStereo
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mpeg1ModeDualChannel
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mpeg1ModeSingleChannel
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)
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// A mepg1FrameHeader is MPEG1 Layer 1-3 frame header
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type mpeg1FrameHeader struct {
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id int // 1 bit
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layer mpeg1Layer // 2 bits
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protection_bit int // 1 bit
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bitrate_index int // 4 bits
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sampling_frequency int // 2 bits
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padding_bit int // 1 bit
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private_bit int // 1 bit
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mode mpeg1Mode // 2 bits
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mode_extension int // 2 bits
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copyright int // 1 bit
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original_or_copy int // 1 bit
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emphasis int // 2 bits
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}
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// A mpeg1SideInfo is MPEG1 Layer 3 Side Information.
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// [2][2] means [gr][ch].
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type mpeg1SideInfo struct {
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main_data_begin int // 9 bits
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private_bits int // 3 bits in mono, 5 in stereo
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scfsi [2][4]int // 1 bit
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part2_3_length [2][2]int // 12 bits
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big_values [2][2]int // 9 bits
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global_gain [2][2]int // 8 bits
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scalefac_compress [2][2]int // 4 bits
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win_switch_flag [2][2]int // 1 bit
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block_type [2][2]int // 2 bits
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mixed_block_flag [2][2]int // 1 bit
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table_select [2][2][3]int // 5 bits
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subblock_gain [2][2][3]int // 3 bits
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region0_count [2][2]int // 4 bits
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region1_count [2][2]int // 3 bits
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preflag [2][2]int // 1 bit
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scalefac_scale [2][2]int // 1 bit
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count1table_select [2][2]int // 1 bit
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count1 [2][2]int // Not in file,calc. by huff.dec.!
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}
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// A mpeg1MainData is MPEG1 Layer 3 Main Data.
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type mpeg1MainData struct {
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scalefac_l [2][2][21]int // 0-4 bits
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scalefac_s [2][2][12][3]int // 0-4 bits
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is [2][2][576]float32 // Huffman coded freq. lines
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}
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type frame struct {
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header mpeg1FrameHeader
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sideInfo mpeg1SideInfo
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mainData mpeg1MainData
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}
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