Files
hacks/find-and-enflac/main.go

122 lines
2.8 KiB
Go

// Command find-and-enflac walks a directory tree, finds every
// uncompressed PCM audio file, and losslessly compresses them all in
// parallel. An original is deleted only after its encoded replacement
// has been verified to decode back to bit-identical audio.
//
// Integer PCM becomes FLAC. IEEE float PCM becomes WavPack, which is
// the only common lossless codec that stores float samples exactly;
// FLAC has no float sample type at all.
package main
import (
"context"
"flag"
"fmt"
"log/slog"
"os"
"os/exec"
"os/signal"
"runtime"
"sync"
"sync/atomic"
"syscall"
)
func main() {
jobs := flag.Int("jobs", runtime.NumCPU(), "files to encode concurrently")
threads := flag.Int("threads", runtime.NumCPU(), "threads per ffmpeg")
dryRun := flag.Bool("n", false, "report what would be done, change nothing")
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "usage: %s [flags] [directory]\n\n", os.Args[0])
fmt.Fprintf(os.Stderr, "Losslessly compress PCM audio under directory (default \".\").\n\n")
flag.PrintDefaults()
}
flag.Parse()
if flag.NArg() > 1 {
flag.Usage()
os.Exit(2)
}
root := "."
if flag.NArg() == 1 {
root = flag.Arg(0)
}
if err := run(root, *jobs, *threads, *dryRun); err != nil {
slog.Error("fatal", "err", err)
os.Exit(1)
}
}
func run(root string, jobs, threads int, dryRun bool) error {
for _, tool := range []string{"ffmpeg", "ffprobe"} {
if _, err := exec.LookPath(tool); err != nil {
return fmt.Errorf("%s not found in PATH: %w", tool, err)
}
}
if jobs < 1 || threads < 1 {
return fmt.Errorf("jobs and threads must be at least 1")
}
info, err := os.Stat(root)
if err != nil {
return err
}
if !info.IsDir() {
return fmt.Errorf("not a directory: %s", root)
}
// Ctrl-C cancels in-flight ffmpeg runs; a killed encode fails
// verification, so its partial output is removed and its source
// is left alone.
ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
defer stop()
srcs, err := findPCM(root)
if err != nil {
return err
}
if len(srcs) == 0 {
slog.Info("no PCM audio found", "root", root)
return nil
}
slog.Info("found PCM audio", "files", len(srcs), "jobs", jobs, "threads", threads)
enc := &encoder{threads: threads, dryRun: dryRun}
var failed atomic.Int64
queue := make(chan string)
var wg sync.WaitGroup
for range jobs {
wg.Go(func() {
for src := range queue {
if err := enc.encodeOne(ctx, src); err != nil {
slog.Error("failed", "src", src, "err", err)
failed.Add(1)
}
}
})
}
for _, src := range srcs {
if ctx.Err() != nil {
break
}
queue <- src
}
close(queue)
wg.Wait()
if n := failed.Load(); n > 0 {
return fmt.Errorf("%d of %d file(s) failed", n, len(srcs))
}
if ctx.Err() != nil {
return ctx.Err()
}
return nil
}