package spotify import ( "fmt" "io/ioutil" "net/url" "os" "os/exec" "strings" ) func EncodeParam(s string) string { return url.QueryEscape(s) } func ToLowerCase(s string) string { var result string for _, char := range s { if char >= 'A' && char <= 'Z' { result += string(char + 32) } else { result += string(char) } } return result } func GetFileSize(file string) (int64, error) { fileInfo, err := os.Stat(file) if err != nil { return 0, err } size := int64(fileInfo.Size()) return size, nil } func DeleteFile(filePath string) { if _, err := os.Stat(filePath); err == nil { if err := os.RemoveAll(filePath); err != nil { fmt.Println("Error deleting file:", err) } } } // Convert M4A file from stereo to mono func ConvertM4aToMono(inputFile, outputFile string) ([]byte, error) { cmd := exec.Command("ffprobe", "-v", "error", "-show_entries", "stream=channels", "-of", "default=noprint_wrappers=1:nokey=1", inputFile) output, err := cmd.CombinedOutput() if err != nil { return nil, fmt.Errorf("error running ffprobe: %v, %v", err, string(output)) } audioBytes, err := ioutil.ReadFile(inputFile) if err != nil { return nil, fmt.Errorf("error reading input file: %v", err) } channels := strings.TrimSpace(string(output)) if channels != "1" { // Convert to mono cmd = exec.Command("ffmpeg", "-i", inputFile, "-af", "pan=mono|c0=c0", outputFile) if err := cmd.Run(); err != nil { return nil, fmt.Errorf("error running ffmpeg: %v", err) } // Resample to 8192 Hz // resampledFile := strings.TrimSuffix(outputFile, filepath.Ext(outputFile)) + "_resampled.m4a" // cmd = exec.Command("ffmpeg", "-i", outputFile, "-ar", "8192", resampledFile) // output, err = cmd.CombinedOutput() // if err := cmd.Run(); err != nil { // return nil, fmt.Errorf("error resampling: %v, %v", err, string(output)) // } audioBytes, err = ioutil.ReadFile(outputFile) if err != nil { return nil, fmt.Errorf("error reading input file: %v", err) } } return audioBytes, nil }