.fix audio analyzer alac

app.go

@@ -1298,6 +1298,14 @@ func (a *App) ReadFileAsBase64(filePath string) (string, error) {
 	return base64.StdEncoding.EncodeToString(content), nil
 }
 
+func (a *App) DecodeAudioForAnalysis(filePath string) (*backend.AnalysisDecodeResponse, error) {
+	if filePath == "" {
+		return nil, fmt.Errorf("file path is required")
+	}
+
+	return backend.DecodeAudioForAnalysis(filePath)
+}
+
 func (a *App) RenameFileTo(oldPath, newName string) error {
 	dir := filepath.Dir(oldPath)
 	ext := filepath.Ext(oldPath)

backend/analysis.go

@@ -1,6 +1,8 @@
 package backend
 
 import (
+	"bytes"
+	"encoding/base64"
 	"fmt"
 	"os"
 	"os/exec"
@@ -24,6 +26,16 @@ type AnalysisResult struct {
 	RMSLevel      float64 `json:"rms_level"`
 }
 
+type AnalysisDecodeResponse struct {
+	PCMBase64     string  `json:"pcm_base64"`
+	SampleRate    uint32  `json:"sample_rate"`
+	Channels      uint8   `json:"channels"`
+	BitsPerSample uint8   `json:"bits_per_sample"`
+	Duration      float64 `json:"duration"`
+	BitrateKbps   int     `json:"bitrate_kbps,omitempty"`
+	BitDepth      string  `json:"bit_depth,omitempty"`
+}
+
 func GetTrackMetadata(filepath string) (*AnalysisResult, error) {
 	if !fileExists(filepath) {
 		return nil, fmt.Errorf("file does not exist: %s", filepath)
@@ -113,3 +125,90 @@ func GetMetadataWithFFprobe(filePath string) (*AnalysisResult, error) {
 
 	return res, nil
 }
+
+func DecodeAudioForAnalysis(filePath string) (*AnalysisDecodeResponse, error) {
+	metadata, err := GetTrackMetadata(filePath)
+	if err != nil {
+		return nil, err
+	}
+
+	pcmBase64, err := extractAnalysisPCMBase64(filePath)
+	if err != nil {
+		return nil, err
+	}
+
+	resp := &AnalysisDecodeResponse{
+		PCMBase64:     pcmBase64,
+		SampleRate:    metadata.SampleRate,
+		Channels:      metadata.Channels,
+		BitsPerSample: metadata.BitsPerSample,
+		Duration:      metadata.Duration,
+		BitDepth:      metadata.BitDepth,
+	}
+
+	if metadata.Bitrate > 0 {
+		resp.BitrateKbps = metadata.Bitrate / 1000
+	}
+
+	return resp, nil
+}
+
+func extractAnalysisPCMBase64(filePath string) (string, error) {
+	ffmpegPath, err := GetFFmpegPath()
+	if err != nil {
+		return "", err
+	}
+
+	argSets := [][]string{
+		{
+			"-v", "error",
+			"-i", filePath,
+			"-vn",
+			"-map", "0:a:0",
+			"-af", "pan=mono|c0=c0",
+			"-f", "s16le",
+			"-acodec", "pcm_s16le",
+			"pipe:1",
+		},
+		{
+			"-v", "error",
+			"-i", filePath,
+			"-vn",
+			"-map", "0:a:0",
+			"-ac", "1",
+			"-f", "s16le",
+			"-acodec", "pcm_s16le",
+			"pipe:1",
+		},
+	}
+
+	var lastErr error
+
+	for _, args := range argSets {
+		var stdout bytes.Buffer
+		var stderr bytes.Buffer
+
+		cmd := exec.Command(ffmpegPath, args...)
+		setHideWindow(cmd)
+		cmd.Stdout = &stdout
+		cmd.Stderr = &stderr
+
+		if err := cmd.Run(); err != nil {
+			lastErr = fmt.Errorf("ffmpeg analysis decode failed: %w - %s", err, strings.TrimSpace(stderr.String()))
+			continue
+		}
+
+		if stdout.Len() == 0 {
+			lastErr = fmt.Errorf("ffmpeg analysis decode returned empty PCM output")
+			continue
+		}
+
+		return base64.StdEncoding.EncodeToString(stdout.Bytes()), nil
+	}
+
+	if lastErr != nil {
+		return "", lastErr
+	}
+
+	return "", fmt.Errorf("ffmpeg analysis decode failed")
+}

frontend/src/hooks/useAudioAnalysis.ts

@@ -2,7 +2,7 @@ import { useState, useCallback, useRef, useEffect, type MutableRefObject } from
 import type { AnalysisResult } from "@/types/api";
 import { logger } from "@/lib/logger";
 import { toastWithSound as toast } from "@/lib/toast-with-sound";
-import { analyzeAudioArrayBuffer, analyzeAudioFile, analyzeSpectrumFromSamples, type AnalysisProgress, } from "@/lib/flac-analysis";
+import { analyzeAudioArrayBuffer, analyzeAudioFile, analyzeDecodedSamples, analyzeSpectrumFromSamples, parseAudioMetadataFromInput, pcm16MonoArrayBufferToFloat32Samples, type AnalysisProgress, type FrontendAnalysisPayload, type ParsedAudioMetadata, } from "@/lib/flac-analysis";
 import { loadAudioAnalysisPreferences } from "@/lib/audio-analysis-preferences";
 type WindowFunction = "hann" | "hamming" | "blackman" | "rectangular";
 function toWindowFunction(value: string): WindowFunction {
@@ -60,6 +60,25 @@ const DEFAULT_PROGRESS_STATE: ProgressState = {
 interface CancelToken {
     cancelled: boolean;
 }
+interface WailsWindow extends Window {
+    go?: {
+        main?: {
+            App?: {
+                ReadFileAsBase64?: (path: string) => Promise<string>;
+                DecodeAudioForAnalysis?: (path: string) => Promise<BackendAnalysisDecodeResponse>;
+            };
+        };
+    };
+}
+interface BackendAnalysisDecodeResponse {
+    pcm_base64: string;
+    sample_rate: number;
+    channels: number;
+    bits_per_sample: number;
+    duration: number;
+    bitrate_kbps?: number;
+    bit_depth?: string;
+}
 function cancelToken(tokenRef: MutableRefObject<CancelToken | null>): void {
     if (tokenRef.current) {
         tokenRef.current.cancelled = true;
@@ -81,6 +100,23 @@ function toProgressState(progress: AnalysisProgress): ProgressState {
         message: progress.message,
     };
 }
+function isDecodeFailure(error: unknown): boolean {
+    return error instanceof Error && /decode/i.test(error.message);
+}
+function mergeBackendDecodedMetadata(parsed: ParsedAudioMetadata, decoded: BackendAnalysisDecodeResponse): ParsedAudioMetadata {
+    const sampleRate = decoded.sample_rate > 0 ? decoded.sample_rate : parsed.sampleRate;
+    const bitsPerSample = decoded.bits_per_sample > 0 ? decoded.bits_per_sample : parsed.bitsPerSample;
+    const duration = decoded.duration > 0 ? decoded.duration : parsed.duration;
+    return {
+        ...parsed,
+        sampleRate,
+        channels: decoded.channels > 0 ? decoded.channels : parsed.channels,
+        bitsPerSample,
+        totalSamples: duration > 0 && sampleRate > 0 ? Math.floor(duration * sampleRate) : parsed.totalSamples,
+        duration,
+        bitrateKbps: decoded.bitrate_kbps ?? parsed.bitrateKbps,
+    };
+}
 export function useAudioAnalysis() {
     const [analyzing, setAnalyzing] = useState(false);
     const [analysisProgress, setAnalysisProgress] = useState<ProgressState>(DEFAULT_PROGRESS_STATE);
@@ -189,7 +225,7 @@ export function useAudioAnalysis() {
             logger.info(`Analyzing audio file (frontend from path): ${filePath}`);
             const start = Date.now();
             const prefs = loadAudioAnalysisPreferences();
-            const readFileAsBase64 = (window as any)?.go?.main?.App?.ReadFileAsBase64 as ((path: string) => Promise<string>) | undefined;
+            const readFileAsBase64 = (window as WailsWindow).go?.main?.App?.ReadFileAsBase64;
             if (!readFileAsBase64) {
                 throw new Error("ReadFileAsBase64 backend method is unavailable");
             }
@@ -211,14 +247,16 @@ export function useAudioAnalysis() {
                 message: "Preparing audio buffer...",
             });
             const fileName = fileNameFromPath(filePath);
-            const payload = await analyzeAudioArrayBuffer({
+            const input = {
                 fileName,
                 fileSize: arrayBuffer.byteLength,
                 arrayBuffer,
-            }, {
+            };
+            const analysisParams = {
                 fftSize: prefs.fftSize,
                 windowFunction: prefs.windowFunction,
-            }, (progress) => {
+            } as const;
+            const updateProgress = (progress: AnalysisProgress) => {
                 if (token.cancelled)
                     return;
                 const mappedPercent = 10 + (progress.percent * 0.9);
@@ -226,7 +264,45 @@ export function useAudioAnalysis() {
                     percent: Math.round(Math.max(0, Math.min(100, mappedPercent))),
                     message: progress.message,
                 });
-            }, () => token.cancelled);
+            };
+            let payload: FrontendAnalysisPayload;
+            try {
+                payload = await analyzeAudioArrayBuffer(input, analysisParams, updateProgress, () => token.cancelled);
+            }
+            catch (err) {
+                if (!isDecodeFailure(err)) {
+                    throw err;
+                }
+                const decodeAudioForAnalysis = (window as WailsWindow).go?.main?.App?.DecodeAudioForAnalysis;
+                if (!decodeAudioForAnalysis) {
+                    throw err;
+                }
+                logger.warning(`Browser decoder failed for ${fileName}; trying FFmpeg fallback`);
+                setAnalysisProgress({
+                    percent: 18,
+                    message: "Browser decoder failed, trying FFmpeg fallback...",
+                });
+                const decoded = await decodeAudioForAnalysis(filePath);
+                if (token.cancelled) {
+                    return null;
+                }
+                setAnalysisProgress({
+                    percent: 24,
+                    message: "Decoding audio with FFmpeg...",
+                });
+                const pcmBase64 = decoded.pcm_base64 || "";
+                if (!pcmBase64) {
+                    throw new Error("FFmpeg analysis decode returned no PCM data");
+                }
+                const pcmBuffer = await base64ToArrayBuffer(pcmBase64, () => token.cancelled);
+                if (token.cancelled) {
+                    return null;
+                }
+                const parsedMetadata = parseAudioMetadataFromInput(input);
+                const mergedMetadata = mergeBackendDecodedMetadata(parsedMetadata, decoded);
+                const samples = pcm16MonoArrayBufferToFloat32Samples(pcmBuffer);
+                payload = await analyzeDecodedSamples(input, mergedMetadata, samples, analysisParams, updateProgress, () => token.cancelled, mergedMetadata.duration);
+            }
             if (token.cancelled) {
                 return null;
             }

frontend/src/lib/flac-analysis.ts

@@ -17,8 +17,8 @@ const MP4_CONTAINER_TYPES = new Set([
     "moov", "trak", "mdia", "minf", "stbl", "edts", "dinf",
     "udta", "ilst", "meta", "stsd", "wave",
 ]);
-type SupportedAudioFileType = "FLAC" | "MP3" | "M4A" | "AAC";
+export type SupportedAudioFileType = "FLAC" | "MP3" | "M4A" | "AAC";
-interface ParsedAudioMetadata {
+export interface ParsedAudioMetadata {
     fileType: SupportedAudioFileType;
     sampleRate: number;
     channels: number;
@@ -417,7 +417,7 @@ function parseM4aMetadata(buffer: ArrayBuffer): ParsedAudioMetadata {
                     }
                 }
             }
-            else if ((box.type === "mp4a" || box.type === "aac ") && box.offset + 36 <= boxEnd) {
+            else if ((box.type === "mp4a" || box.type === "aac " || box.type === "alac") && box.offset + 36 <= boxEnd) {
                 channels = view.getUint16(box.offset + 24, false) || channels;
                 bitsPerSample = view.getUint16(box.offset + 26, false) || bitsPerSample;
                 if (!sampleRate) {
@@ -455,7 +455,7 @@ function parseM4aMetadata(buffer: ArrayBuffer): ParsedAudioMetadata {
         duration,
     };
 }
-function parseAudioMetadata(input: AudioArrayBufferInput): ParsedAudioMetadata {
+export function parseAudioMetadataFromInput(input: AudioArrayBufferInput): ParsedAudioMetadata {
     const fileType = detectAudioFileType(input.arrayBuffer, input.fileName);
     switch (fileType) {
         case "FLAC": return parseFlacMetadata(input.arrayBuffer);
@@ -465,6 +465,15 @@ function parseAudioMetadata(input: AudioArrayBufferInput): ParsedAudioMetadata {
         default: throw new Error(`Unsupported audio format: ${input.fileName || "unknown"}`);
     }
 }
+export function pcm16MonoArrayBufferToFloat32Samples(buffer: ArrayBuffer): Float32Array {
+    const sampleCount = Math.floor(buffer.byteLength / 2);
+    const samples = new Float32Array(sampleCount);
+    const view = new DataView(buffer);
+    for (let i = 0; i < sampleCount; i++) {
+        samples[i] = view.getInt16(i * 2, true) / 32768;
+    }
+    return samples;
+}
 function buildWindowCoefficients(size: number, windowFunction: SpectrumParams["windowFunction"]): Float32Array {
     const coeffs = new Float32Array(size);
     if (size <= 1) {
@@ -649,7 +658,7 @@ export async function analyzeAudioFile(file: File, params: SpectrumParams = DEFA
 export async function analyzeAudioArrayBuffer(input: AudioArrayBufferInput, params: SpectrumParams = DEFAULT_PARAMS, onProgress?: AnalysisProgressCallback, shouldCancel?: AnalysisCancelCheck): Promise<FrontendAnalysisPayload> {
     throwIfCancelled(shouldCancel);
     reportProgress(onProgress, "parse", 5, "Parsing audio metadata...");
-    const metadata = parseAudioMetadata(input);
+    const metadata = parseAudioMetadataFromInput(input);
     throwIfCancelled(shouldCancel);
     reportProgress(onProgress, "decode", 15, "Decoding audio stream...");
     const audioContext = createAnalysisAudioContext(metadata.sampleRate);
@@ -658,6 +667,17 @@ export async function analyzeAudioArrayBuffer(input: AudioArrayBufferInput, para
         throwIfCancelled(shouldCancel);
         reportProgress(onProgress, "decode", 35, "Audio decoded");
         const samples = audioBuffer.getChannelData(0);
+        return analyzeDecodedSamples(input, metadata, samples, params, onProgress, shouldCancel, audioBuffer.duration);
+    }
+    finally {
+        await audioContext.close();
+    }
+}
+export async function analyzeDecodedSamples(input: AudioArrayBufferInput, metadata: ParsedAudioMetadata, samples: Float32Array, params: SpectrumParams = DEFAULT_PARAMS, onProgress?: AnalysisProgressCallback, shouldCancel?: AnalysisCancelCheck, durationOverride?: number): Promise<FrontendAnalysisPayload> {
+    throwIfCancelled(shouldCancel);
+    const analysisSampleRate = metadata.sampleRate > 0 ? metadata.sampleRate : 44100;
+    const analysisChannels = metadata.channels > 0 ? metadata.channels : 1;
+    const bitDepthLabel = metadata.bitsPerSample > 0 ? `${metadata.bitsPerSample}-bit` : "Unknown";
     reportProgress(onProgress, "metrics", 40, "Calculating peak/RMS...");
     let peak = 0;
     let sumSquares = 0;
@@ -670,7 +690,7 @@ export async function analyzeAudioArrayBuffer(input: AudioArrayBufferInput, para
             peak = absSample;
         sumSquares += sample * sample;
         if ((i + 1) % METRICS_CHUNK_SIZE === 0 || i === samples.length - 1) {
-                const metricsProgress = 40 + (((i + 1) / samples.length) * 10);
+            const metricsProgress = 40 + (((i + 1) / Math.max(1, samples.length)) * 10);
             reportProgress(onProgress, "metrics", metricsProgress, "Calculating peak/RMS...");
             const now = nowMs();
             if (now - lastMetricsYieldAt >= 16) {
@@ -684,12 +704,16 @@ export async function analyzeAudioArrayBuffer(input: AudioArrayBufferInput, para
     const rms = samples.length > 0 ? Math.sqrt(sumSquares / samples.length) : 0;
     const rmsDB = rms > 0 ? 20 * Math.log10(rms) : -120;
     const dynamicRange = peakDB - rmsDB;
-        const duration = audioBuffer.duration > 0 ? audioBuffer.duration : metadata.duration;
+    const duration = durationOverride && durationOverride > 0
+        ? durationOverride
+        : (metadata.duration > 0
+            ? metadata.duration
+            : (analysisSampleRate > 0 ? samples.length / analysisSampleRate : 0));
     const totalSamples = metadata.totalSamples > 0
         ? metadata.totalSamples
-            : Math.floor(duration * metadata.sampleRate);
+        : (duration > 0 ? Math.floor(duration * analysisSampleRate) : samples.length);
     reportProgress(onProgress, "metrics", 50, "Signal metrics complete");
-        const spectrum = await analyzeSpectrumFromSamples(samples, metadata.sampleRate, params, (progress) => {
+    const spectrum = await analyzeSpectrumFromSamples(samples, analysisSampleRate, params, (progress) => {
         const mappedPercent = 50 + (progress.percent * 0.45);
         reportProgress(onProgress, "spectrum", mappedPercent, progress.message);
     }, shouldCancel);
@@ -699,12 +723,12 @@ export async function analyzeAudioArrayBuffer(input: AudioArrayBufferInput, para
             file_path: input.fileName,
             file_size: input.fileSize,
             file_type: metadata.fileType,
-                sample_rate: metadata.sampleRate,
+            sample_rate: analysisSampleRate,
-                channels: metadata.channels || audioBuffer.numberOfChannels,
+            channels: analysisChannels,
             bits_per_sample: metadata.bitsPerSample,
             total_samples: totalSamples,
             duration,
-                bit_depth: `${metadata.bitsPerSample}-bit`,
+            bit_depth: bitDepthLabel,
             dynamic_range: dynamicRange,
             peak_amplitude: peakDB,
             rms_level: rmsDB,
@@ -719,9 +743,5 @@ export async function analyzeAudioArrayBuffer(input: AudioArrayBufferInput, para
     reportProgress(onProgress, "finalize", 100, "Analysis complete");
     return payload;
 }
-    finally {
-        await audioContext.close();
-    }
-}
 export const analyzeFlacFile = analyzeAudioFile;
 export const analyzeFlacArrayBuffer = analyzeAudioArrayBuffer;