From 1b7d30292c0d6233f38121366adc400cb4be029a Mon Sep 17 00:00:00 2001
From: Leo Tenenbaum <pommicket@gmail.com>
Date: Sun, 16 Jun 2019 12:46:14 -0400
Subject: Initial commit

---
 autoutils/audio.go | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 autoutils/audio.go

(limited to 'autoutils/audio.go')

diff --git a/autoutils/audio.go b/autoutils/audio.go
new file mode 100644
index 0000000..19ae5f3
--- /dev/null
+++ b/autoutils/audio.go
@@ -0,0 +1,83 @@
+/*
+Copyright (C) 2019 Leo Tenenbaum
+
+This file is part of AutoArt.
+
+AutoArt is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+AutoArt is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with AutoArt.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+package autoutils
+
+import (
+    "io"
+    "encoding/binary"
+)
+
+// Write a header to writer. You need to decide ahead of time how many samples
+// you want.
+func WriteAudioHeader(writer io.Writer, nSamples int64, channels, sampleRate int32) error {
+    w := func (data interface{}) error {
+        return binary.Write(writer, binary.LittleEndian, data)
+    }
+    var err error
+    if err = w([]byte("RIFF")); err != nil { return err }
+    var chunkSize1 uint32 = 36 + uint32(nSamples)
+    if err = w(chunkSize1); err != nil { return err }
+    if err = w([]byte("WAVEfmt ")); err != nil { return err }
+    var subchunk1size uint32 = 16
+    if err = w(subchunk1size); err != nil { return err }
+    var audioFormat uint16 = 1
+    if err = w(audioFormat); err != nil { return err }
+    var nChannels uint16 = uint16(channels)
+    if err = w(nChannels); err != nil { return err }
+    var srate uint32 = uint32(sampleRate)
+    if err = w(srate); err != nil { return err }
+    var byteRate uint32 = srate * uint32(nChannels)
+    if err = w(byteRate); err != nil { return err }
+    var blockAlign uint16 = nChannels
+    if err = w(blockAlign); err != nil { return err }
+    var bitsPerSample uint16 = 8
+    if err = w(bitsPerSample); err != nil { return err }
+    if err = w([]byte("data")); err != nil { return err }
+    var chunkSize2 uint32 = uint32(nSamples) * uint32(nChannels)
+    if err = w(chunkSize2); err != nil { return err }
+    return nil
+}
+
+
+// Writes some samples to the writer. You will need to write a header before
+// any samples.
+func WriteAudioSamples(writer io.Writer, samples []uint8) error {
+    return binary.Write(writer, binary.LittleEndian, samples)
+}
+
+/*
+Writes audio data in WAV format to the writer. There is only support for 8-bit
+audio. If there are multiple channels, audio[0] should refer to the first sample
+for the first channel, audio[1] should refer to the first sample for the second
+channel, etc.
+WAV does not support more then 65535 channels (but what are you doing if
+you're using that many?!)
+*/
+func WriteAudio(writer io.Writer, audio []uint8, channels, sampleRate int32) error {
+
+    err := WriteAudioHeader(writer, int64(len(audio)), channels, sampleRate)
+    if err != nil {
+        return err
+    }
+    if err = WriteAudioSamples(writer, audio); err != nil {
+        return err
+    }
+    return nil
+}
-- 
cgit v1.2.3