mirror of
https://github.com/hajimehoshi/ebiten.git
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f0ef1ecad0
This change adds these APIs * (*audio.Context).NewPlayerF32 * (*audio.Context).NewPlayerF32FromBytes * audio.NewInfiniteLoopF32 * audio.NewInfiniteLoopWithIntroF32 * audio.ResampleF32 * mp3.DecodeF32 * vorbis.DecodeF32 * wav.DecodeF32 Closes #2160
277 lines
9.4 KiB
Go
277 lines
9.4 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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package audio
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import (
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"fmt"
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"io"
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"math"
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)
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// InfiniteLoop represents a looped stream which never ends.
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type InfiniteLoop struct {
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src io.ReadSeeker
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lstart int64
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llength int64
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pos int64
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bitDepthInBytes int
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bytesPerSample int
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// extra is the remainder in the case when the read byte sizes are not multiple of the bit depth.
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extra []byte
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// afterLoop is data after the loop.
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afterLoop []byte
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// blending represents whether the loop start and afterLoop are blended or not.
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blending bool
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noBlendForTesting bool
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}
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// NewInfiniteLoop creates a new infinite loop stream with a source stream and length in bytes.
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//
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// src is a signed 16bit integer little endian stream, 2 channels (stereo).
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//
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// If the loop's total length is exactly the same as src's length, you might hear noises around the loop joint.
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// This noise can be heard especially when src is decoded from a lossy compression format like Ogg/Vorbis and MP3.
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// In this case, try to add more (about 0.1[s]) data to src after the loop end.
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// If src has data after the loop end, an InfiniteLoop uses part of the data to blend with the loop start
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// to make the loop joint smooth.
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func NewInfiniteLoop(src io.ReadSeeker, length int64) *InfiniteLoop {
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return newInfiniteLoopWithIntro(src, 0, length, bitDepthInBytesInt16)
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}
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// NewInfiniteLoopF32 creates a new infinite loop stream with a source stream and length in bytes.
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//
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// src is a 32bit float little endian stream, 2 channels (stereo).
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//
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// If the loop's total length is exactly the same as src's length, you might hear noises around the loop joint.
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// This noise can be heard especially when src is decoded from a lossy compression format like Ogg/Vorbis and MP3.
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// In this case, try to add more (about 0.1[s]) data to src after the loop end.
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// If src has data after the loop end, an InfiniteLoop uses part of the data to blend with the loop start
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// to make the loop joint smooth.
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func NewInfiniteLoopF32(src io.ReadSeeker, length int64) *InfiniteLoop {
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return newInfiniteLoopWithIntro(src, 0, length, bitDepthInBytesFloat32)
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}
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// NewInfiniteLoopWithIntro creates a new infinite loop stream with an intro part.
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// NewInfiniteLoopWithIntro accepts a source stream src, introLength in bytes and loopLength in bytes.
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//
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// src is a signed 16bit integer little endian stream, 2 channels (stereo).
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//
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// If the loop's total length is exactly the same as src's length, you might hear noises around the loop joint.
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// This noise can be heard especially when src is decoded from a lossy compression format like Ogg/Vorbis and MP3.
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// In this case, try to add more (about 0.1[s]) data to src after the loop end.
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// If src has data after the loop end, an InfiniteLoop uses part of the data to blend with the loop start
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// to make the loop joint smooth.
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func NewInfiniteLoopWithIntro(src io.ReadSeeker, introLength int64, loopLength int64) *InfiniteLoop {
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return newInfiniteLoopWithIntro(src, introLength, loopLength, bitDepthInBytesInt16)
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}
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// NewInfiniteLoopWithIntroF32 creates a new infinite loop stream with an intro part.
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// NewInfiniteLoopWithIntroF32 accepts a source stream src, introLength in bytes and loopLength in bytes.
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//
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// src is a 32bit float little endian stream, 2 channels (stereo).
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//
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// If the loop's total length is exactly the same as src's length, you might hear noises around the loop joint.
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// This noise can be heard especially when src is decoded from a lossy compression format like Ogg/Vorbis and MP3.
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// In this case, try to add more (about 0.1[s]) data to src after the loop end.
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// If src has data after the loop end, an InfiniteLoop uses part of the data to blend with the loop start
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// to make the loop joint smooth.
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func NewInfiniteLoopWithIntroF32(src io.ReadSeeker, introLength int64, loopLength int64) *InfiniteLoop {
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return newInfiniteLoopWithIntro(src, introLength, loopLength, bitDepthInBytesFloat32)
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}
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func newInfiniteLoopWithIntro(src io.ReadSeeker, introLength int64, loopLength int64, bitDepthInBytes int) *InfiniteLoop {
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bytesPerSample := bitDepthInBytes * channelCount
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return &InfiniteLoop{
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src: src,
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lstart: introLength / int64(bytesPerSample) * int64(bytesPerSample),
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llength: loopLength / int64(bytesPerSample) * int64(bytesPerSample),
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pos: -1,
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bitDepthInBytes: bitDepthInBytes,
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bytesPerSample: bytesPerSample,
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}
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}
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func (i *InfiniteLoop) length() int64 {
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return i.lstart + i.llength
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}
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func (i *InfiniteLoop) ensurePos() error {
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if i.pos >= 0 {
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return nil
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}
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pos, err := i.src.Seek(0, io.SeekCurrent)
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if err != nil {
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return err
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}
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if pos >= i.length() {
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return fmt.Errorf("audio: stream position must be less than the specified length")
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}
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i.pos = pos
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return nil
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}
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func (i *InfiniteLoop) blendRate(pos int64) float32 {
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if pos < i.lstart {
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return 0
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}
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if pos >= i.lstart+int64(len(i.afterLoop)) {
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return 0
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}
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p := (pos - i.lstart) / int64(i.bytesPerSample)
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l := len(i.afterLoop) / i.bytesPerSample
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return 1 - float32(p)/float32(l)
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}
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// Read is implementation of ReadSeeker's Read.
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func (i *InfiniteLoop) Read(b []byte) (int, error) {
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if err := i.ensurePos(); err != nil {
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return 0, err
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}
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if i.pos+int64(len(b)) > i.length() {
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b = b[:i.length()-i.pos]
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}
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extralen := len(i.extra)
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copy(b, i.extra)
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i.extra = i.extra[:0]
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n, err := i.src.Read(b[extralen:])
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n += extralen
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i.pos += int64(n)
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if i.pos > i.length() {
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panic(fmt.Sprintf("audio: position must be <= length but not at (*InfiniteLoop).Read: pos: %d, length: %d", i.pos, i.length()))
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}
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// Save the remainder part to extra. This will be used at the next Read.
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if rem := n % i.bitDepthInBytes; rem != 0 {
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i.extra = append(i.extra, b[n-rem:n]...)
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b = b[:n-rem]
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n = n - rem
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}
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// Blend afterLoop and the loop start to reduce noises (#1888).
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// Ideally, afterLoop and the loop start should be identical, but they can have very slight differences.
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if !i.noBlendForTesting && i.blending && i.pos >= i.lstart && i.pos-int64(n) < i.lstart+int64(len(i.afterLoop)) {
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if n%i.bitDepthInBytes != 0 {
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panic(fmt.Sprintf("audio: n must be a multiple of bit depth %d [bytes] but not: %d", i.bitDepthInBytes, n))
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}
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for idx := 0; idx < n/i.bitDepthInBytes; idx++ {
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abspos := i.pos - int64(n) + int64(idx)*int64(i.bitDepthInBytes)
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rate := i.blendRate(abspos)
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if rate == 0 {
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continue
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}
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relpos := abspos - i.lstart
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switch i.bitDepthInBytes {
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case 2:
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afterLoop := int16(i.afterLoop[relpos]) | (int16(i.afterLoop[relpos+1]) << 8)
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orig := int16(b[2*idx]) | (int16(b[2*idx+1]) << 8)
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newVal := int16(float32(afterLoop)*rate + float32(orig)*(1-rate))
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b[2*idx] = byte(newVal)
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b[2*idx+1] = byte(newVal >> 8)
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case 4:
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afterLoop := math.Float32frombits(uint32(i.afterLoop[relpos]) | (uint32(i.afterLoop[relpos+1]) << 8) | (uint32(i.afterLoop[relpos+2]) << 16) | (uint32(i.afterLoop[relpos+3]) << 24))
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orig := math.Float32frombits(uint32(b[4*idx]) | (uint32(b[4*idx+1]) << 8) | (uint32(b[4*idx+2]) << 16) | (uint32(b[4*idx+3]) << 24))
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newVal := float32(afterLoop*rate + orig*(1-rate))
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newValBits := math.Float32bits(newVal)
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b[4*idx] = byte(newValBits)
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b[4*idx+1] = byte(newValBits >> 8)
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b[4*idx+2] = byte(newValBits >> 16)
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b[4*idx+3] = byte(newValBits >> 24)
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default:
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panic("not reached")
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}
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}
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}
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if err != nil && err != io.EOF {
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return 0, err
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}
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// Read the afterLoop part if necessary.
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if i.pos == i.length() && err == nil {
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if i.afterLoop == nil {
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buflen := int64(256 * i.bytesPerSample)
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if buflen > i.length() {
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buflen = i.length()
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}
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buf := make([]byte, buflen)
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pos := 0
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for pos < len(buf) {
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n, err := i.src.Read(buf[pos:])
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if err != nil && err != io.EOF {
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return 0, err
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}
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pos += n
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if err == io.EOF {
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break
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}
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}
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i.afterLoop = buf[:pos]
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}
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if len(i.afterLoop) > 0 {
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i.blending = true
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}
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}
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if i.pos == i.length() || err == io.EOF {
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// Ignore the new position returned by Seek since the source position might not be match with the position
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// managed by this.
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if _, err := i.src.Seek(i.lstart, io.SeekStart); err != nil {
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return 0, err
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}
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i.pos = i.lstart
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}
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return n, nil
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}
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// Seek is implementation of ReadSeeker's Seek.
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func (i *InfiniteLoop) Seek(offset int64, whence int) (int64, error) {
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i.blending = false
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if err := i.ensurePos(); err != nil {
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return 0, err
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}
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next := int64(0)
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switch whence {
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case io.SeekStart:
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next = offset
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case io.SeekCurrent:
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next = i.pos + offset
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case io.SeekEnd:
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return 0, fmt.Errorf("audio: whence must be io.SeekStart or io.SeekCurrent for InfiniteLoop")
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}
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if next < 0 {
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return 0, fmt.Errorf("audio: position must >= 0")
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}
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if next > i.lstart {
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next = ((next - i.lstart) % i.llength) + i.lstart
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}
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// Ignore the new position returned by Seek since the source position might not be match with the position
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// managed by this.
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if _, err := i.src.Seek(next, io.SeekStart); err != nil {
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return 0, err
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}
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i.pos = next
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return i.pos, nil
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}
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