av/cmd/adpcm/decode-pcm/decode-pcm.go

76 lines
2.1 KiB
Go

/*
NAME
decode-pcm.go
DESCRIPTION
decode-pcm.go is a program for decoding/decompressing an adpcm file to a pcm file.
AUTHOR
Trek Hopton <trek@ausocean.org>
LICENSE
decode-pcm.go is Copyright (C) 2018 the Australian Ocean Lab (AusOcean)
It is free software: you can redistribute it and/or modify them
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.
It 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 revid in gpl.txt. If not, see [GNU licenses](http://www.gnu.org/licenses).
*/
package main
import (
"flag"
"fmt"
"io/ioutil"
"log"
"bitbucket.org/ausocean/av/stream/adpcm"
)
// This program accepts an input file encoded in adpcm and outputs a decoded pcm file.
// Input and output file names can be specified as arguments.
func main() {
var inPath string
var outPath string
flag.StringVar(&inPath, "in", "encoded.adpcm", "file path of input")
flag.StringVar(&outPath, "out", "decoded.pcm", "file path of output data")
flag.Parse()
// read adpcm
comp, err := ioutil.ReadFile(inPath)
if err != nil {
log.Fatal(err)
}
fmt.Println("Read", len(comp), "bytes from file", inPath)
// decode adpcm
inBSize := 256
numBlocks := int(len(comp) / inBSize)
outBSize := 2 + (inBSize-4)*4 // 2 bytes are copied, 2 are used as block header info, the remaining bytes are decompressed 1:4
decoded := make([]byte, 0, outBSize*numBlocks)
for i := 0; i < numBlocks; i++ {
block := comp[inBSize*i : inBSize*(i+1)]
decBlock, err := adpcm.DecodeBlock(block)
if err != nil {
log.Fatal(err)
}
decoded = append(decoded, decBlock...)
}
// save pcm to file
err = ioutil.WriteFile(outPath, decoded, 0644)
if err != nil {
log.Fatal(err)
}
fmt.Println("Decoded and wrote", len(decoded), "bytes to file", outPath)
}