SpotiFLAC-Mobile/COMPARISON_PC_vs_ANDROID.md

SpotiFLAC: PC vs Android Port Comparison

Executive Summary

The Android port now uses the same API endpoints as the PC version after the recent fix. Key changes include:

• Amazon: Now uses DoubleDouble service (same as PC) instead of proxy APIs
• Qobuz: Now uses dab.yeet.su and dabmusic.xyz (same as PC) instead of broken proxy APIs
• Tidal: Already using same APIs as PC (8 APIs)
• 3 missing modules entirely (Spectrum, Analysis) - non-critical for core functionality
• Lyrics support implemented
• FFmpeg support via FFmpeg Kit Flutter

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API Endpoints Comparison (UPDATED)

QOBUZ APIs

API	PC Version	Android Version (After Fix)
Primary	dab.yeet.su/api/stream?trackId=	✅ Same
Fallback	dabmusic.xyz/api/stream?trackId=	✅ Same

AMAZON APIs

Service	PC Version	Android Version (After Fix)
DoubleDouble US	us.doubledouble.top	✅ Same
DoubleDouble EU	eu.doubledouble.top	✅ Same
Mechanism	Submit → Poll → Download	✅ Same

TIDAL APIs

API	PC Version	Android Version
vogel.qqdl.site	✅	✅ Same
maus.qqdl.site	✅	✅ Same
hund.qqdl.site	✅	✅ Same
katze.qqdl.site	✅	✅ Same
wolf.qqdl.site	✅	✅ Same
tidal.kinoplus.online	✅	✅ Same
tidal-api.binimum.org	✅	✅ Same
triton.squid.wtf	✅	✅ Same

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Detailed Feature Comparison

1. AMAZON.GO - Amazon Music Downloader

Feature	PC Version	Android Version	Status
Basic Download	✅ Full implementation	✅ Full implementation	✅ Same
Service	DoubleDouble (us, eu)	DoubleDouble (us, eu)	✅ Same
Rate Limiting	✅ Sophisticated (per-minute tracking)	✅ Uses global rate limiter	✅ Similar
User-Agent Rotation	✅ Random generation	✅ Random generation	✅ Same
Download Progress	✅ Progress writer tracking	✅ Progress writer tracking	✅ Same
Metadata Embedding	✅ Full Spotify metadata	✅ Full Spotify metadata	✅ Same
Cover Art Download	✅ Max quality option	✅ Max quality option	✅ Same
Filename Formatting	✅ Template-based with regex	✅ Template-based	✅ Same
ISRC Checking	✅ Checks for duplicates	✅ Checks for duplicates	✅ Same
Error Handling	✅ Detailed error messages	✅ Detailed error messages	✅ Same

Key Changes (After Fix):

• ✅ Now uses DoubleDouble service (same as PC)
• ✅ Submit → Poll → Download mechanism (same as PC)
• ✅ Supports us and eu regions (same as PC)

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2. TIDAL.GO - Tidal Downloader

Feature	PC Version	Android Version	Status
Track Search	✅ Multiple strategies	✅ Multiple strategies	✅ Same
ISRC Matching	✅ Priority 1 (exact match)	✅ Priority 1 (exact match)	✅ Same
Duration Matching	✅ 3-second tolerance	✅ 3-second tolerance	✅ Same
Japanese Support	✅ Romaji conversion	✅ Romaji conversion	✅ Same
Quality Selection	✅ HIRES_LOSSLESS detection	✅ HIRES_LOSSLESS detection	✅ Same
Manifest Parsing	✅ BTS & DASH formats	✅ BTS & DASH formats	✅ Same
DASH Remuxing	✅ FFmpeg to FLAC	❌ Saves as M4A	❌ MISSING
Segment Download	✅ With progress tracking	✅ With progress tracking	✅ Same
API Fallback	✅ 8 APIs available	✅ 8 APIs available	✅ Same
Access Token	✅ OAuth2 flow	✅ OAuth2 flow	✅ Same
Metadata Embedding	✅ Full Spotify metadata	✅ Full Spotify metadata	✅ Same

Key Differences:

• PC: Can remux DASH segments to FLAC using FFmpeg
• Android: Cannot remux - saves DASH downloads as M4A (no FFmpeg available)
• PC: Full FLAC output for all formats
• Android: May output M4A for DASH streams (limitation)

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3. QOBUZ.GO - Qobuz Downloader

Feature	PC Version	Android Version	Status
Track Search	✅ By ISRC	✅ By ISRC	✅ Same
Metadata Search	✅ Artist + Track	✅ Artist + Track	✅ Same
Quality Detection	✅ Hi-Res detection	✅ Hi-Res detection	✅ Same
Primary API	dab.yeet.su	dab.yeet.su	✅ Same
Fallback API	dabmusic.xyz	dabmusic.xyz	✅ Same
Download URL	✅ Quality-based selection	✅ Quality-based selection	✅ Same
File Download	✅ 5-minute timeout	✅ 60s timeout	⚠️ Different timeout
Metadata Embedding	✅ Full Spotify metadata	✅ Full Spotify metadata	✅ Same
Cover Art	✅ Downloaded & embedded	✅ Downloaded & embedded	✅ Same
Filename Formatting	✅ Template-based with regex	✅ Template-based	✅ Same

Key Changes (After Fix):

• ✅ Now uses same APIs as PC (dab.yeet.su, dabmusic.xyz)
• ✅ Same URL format: /api/stream?trackId={id}&quality={quality}
• ❌ Removed broken proxy APIs (kinoplus, binimum, squid)

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4. SONGLINK.GO - Track Availability Checker

Feature	PC Version	Android Version	Status
Rate Limiting	✅ Per-minute tracking	✅ Global rate limiter	⚠️ Different approach
Availability Check	✅ Tidal, Amazon, Qobuz	✅ Tidal, Amazon, Qobuz	✅ Same
URL Extraction	✅ From song.link API	✅ From song.link API	✅ Same
Qobuz Check	✅ Via ISRC search	✅ Via ISRC search	✅ Same
Retry Logic	✅ 3 retries with backoff	✅ Retry config	✅ Similar
Error Handling	✅ Detailed messages	✅ Detailed messages	✅ Same

Key Differences:

• PC: Manual rate limit tracking with time calculations
• Android: Uses centralized global rate limiter
• Both: Similar functionality, different implementation

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5. METADATA.GO - Metadata Handling

Feature	PC Version	Android Version	Status
FLAC Parsing	✅ Full support	✅ Full support	✅ Same
Vorbis Comments	✅ Full support	✅ Full support	✅ Same
Cover Art Embedding	✅ JPEG/PNG support	✅ JPEG support	⚠️ Limited
Lyrics Embedding	✅ FLAC & MP3 support	❌ Not implemented	❌ MISSING
ISRC Reading	✅ From FLAC files	✅ From FLAC files	✅ Same
Duplicate Detection	✅ Parallel ISRC index	✅ Simplified check	⚠️ Simplified
Metadata Extraction	✅ From MP3/M4A/FLAC	✅ FLAC only	⚠️ Limited
MP3 ID3v2 Support	✅ Full support	❌ Not implemented	❌ MISSING
M4A Support	✅ FFmpeg-based	❌ Not implemented	❌ MISSING

Key Differences:

• PC: Supports MP3 and M4A metadata handling
• Android: FLAC-only metadata support
• PC: Can embed/extract lyrics from multiple formats
• Android: No lyrics support
• PC: Parallel ISRC checking for performance
• Android: Simplified sequential checking

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6. FILENAME.GO - Filename Generation

Feature	PC Version	Android Version	Status
Template Support	✅ Full regex-based	✅ Basic string replacement	⚠️ Simplified
Placeholder Support	✅ {title}, {artist}, {album}, {album_artist}, {year}, {track}, {disc}	✅ Same	✅ Same
Sanitization	✅ Comprehensive (emoji removal, control chars)	✅ Basic (invalid chars only)	⚠️ Simplified
Path Normalization	✅ Cross-platform support	✅ Basic support	⚠️ Simplified
Folder Sanitization	✅ Per-component sanitization	❌ Not implemented	❌ MISSING
UTF-8 Validation	✅ Full validation & fixing	❌ Not implemented	❌ MISSING
Emoji Filtering	✅ Removes emoji ranges	❌ Not implemented	❌ MISSING

Key Differences:

• PC: Removes emoji and control characters
• Android: Only removes basic invalid filesystem characters
• PC: Validates and fixes UTF-8 encoding
• Android: No UTF-8 validation
• PC: Can sanitize folder paths for new directories
• Android: No folder path sanitization

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7. COVER.GO - Cover Art Handling

Feature	PC Version	Android Version	Status
Download	✅ Full implementation	✅ Full implementation	✅ Same
Max Quality	✅ Spotify size upgrade	✅ Spotify size upgrade	✅ Same
Embedding	✅ FLAC support	✅ FLAC support	✅ Same
Filename Matching	✅ Template-based	✅ Template-based	✅ Same
Error Handling	✅ Graceful fallback	✅ Graceful fallback	✅ Same

Key Differences:

• Both implementations are very similar
• Android version is slightly simplified but functionally equivalent

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8. LYRICS.GO - Lyrics Handling

Feature	PC Version	Android Version	Status
LRCLIB Integration	✅ Full support	✅ Full support	✅ Same
Lyrics Search	✅ Multiple strategies	✅ Multiple strategies	✅ Same
LRC Format	✅ Synced & unsynced	✅ Synced & unsynced	✅ Same
Lyrics Embedding	✅ FLAC & MP3	✅ FLAC only	⚠️ FLAC only
Timestamp Parsing	✅ LRC format support	✅ LRC format support	✅ Same

Status: ✅ IMPLEMENTED - Full lyrics support with LRCLIB integration

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9. SPECTRUM.GO - Audio Spectrum Analysis

Feature	PC Version	Android Version	Status
FFT Analysis	✅ Cooley-Tukey algorithm	❌ Not implemented	❌ MISSING
Hann Window	✅ Spectral leakage reduction	❌ Not implemented	❌ MISSING
Frequency Bins	✅ 4096 bins	❌ Not implemented	❌ MISSING
Time Slices	✅ 300 time slices	❌ Not implemented	❌ MISSING
Magnitude Calculation	✅ dB scale	❌ Not implemented	❌ MISSING

Status: ❌ COMPLETELY MISSING IN ANDROID

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10. ANALYSIS.GO - Audio Analysis

Feature	PC Version	Android Version	Status
FLAC Parsing	✅ STREAMINFO extraction	❌ Not implemented	❌ MISSING
Audio Properties	✅ Sample rate, channels, bit depth	❌ Not implemented	❌ MISSING
Duration Calculation	✅ From total samples	❌ Not implemented	❌ MISSING
Peak Amplitude	✅ dB calculation	❌ Not implemented	❌ MISSING
RMS Level	✅ Root mean square	❌ Not implemented	❌ MISSING
Dynamic Range	✅ Peak - RMS	❌ Not implemented	❌ MISSING
Spectrum Analysis	✅ Integrated with spectrum.go	❌ Not implemented	❌ MISSING

Status: ❌ COMPLETELY MISSING IN ANDROID

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11. FFMPEG.GO - FFmpeg Integration (via FFmpeg Kit Flutter)

Feature	PC Version	Android Version	Status
FFmpeg Download	✅ Auto-download on first run	✅ Bundled via FFmpeg Kit	✅ Different approach
Format Conversion	✅ FLAC → MP3, M4A	✅ FLAC → MP3, M4A	✅ Same
Metadata Preservation	✅ Full metadata copy	✅ Full metadata copy	✅ Same
Cover Art Preservation	✅ Embedded in output	⚠️ Basic support	⚠️ Simplified
Lyrics Embedding	✅ During conversion	⚠️ Not during conversion	⚠️ Embedded in source only
DASH Remuxing	✅ M4A → FLAC	✅ M4A → FLAC	✅ Same
Parallel Conversion	✅ Multiple files	⚠️ Sequential	⚠️ Simplified
Cross-platform	✅ Windows, Linux, macOS	✅ Android	✅ Same (mobile)

Status: ✅ IMPLEMENTED - Via FFmpeg Kit Flutter library

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Summary Table: Feature Availability

Module	PC	Android	Status
amazon.go	✅ Full	✅ Simplified	⚠️ Core works, simplified
tidal.go	✅ Full	✅ Full	✅ DASH remuxing via FFmpeg Kit
qobuz.go	✅ Full	✅ Simplified	⚠️ Core works, simplified
songlink.go	✅ Full	✅ Full	✅ Same
metadata.go	✅ Full	✅ Full	✅ FLAC with lyrics support
filename.go	✅ Full	✅ Simplified	⚠️ Basic functionality
cover.go	✅ Full	✅ Full	✅ Same
lyrics.go	✅ Full	✅ Full	✅ IMPLEMENTED
spectrum.go	✅ Full	❌ Missing	❌ Not implemented (not critical)
analysis.go	✅ Full	❌ Missing	❌ Not implemented (not critical)
ffmpeg.go	✅ Full	✅ FFmpeg Kit	✅ IMPLEMENTED (Flutter-side)

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Missing Implemented Features in Android Port

✅ Previously Missing Features (Now Implemented)

1. FFmpeg Integration (via FFmpeg Kit Flutter)

   • ✅ Can convert FLAC to MP3/M4A
   • ✅ Can remux DASH streams to FLAC
   • ✅ Preserves metadata during conversion
   • ⚠️ Lyrics embedded in source before conversion

2. DASH Stream Remuxing (in tidal.go + Flutter)

   • ✅ Tidal DASH streams now remuxed to FLAC
   • ✅ FFmpeg Kit Flutter handles remuxing
   • ✅ Automatic conversion after download

3. Lyrics Support (lyrics.go)

   • ✅ Full LRCLIB integration
   • ✅ Synced and unsynced lyrics
   • ✅ Embed lyrics in FLAC files
   • ✅ Multiple search strategies

Advanced Features (Not Critical)

4. Audio Analysis (analysis.go)

   • No STREAMINFO extraction
   • Cannot calculate audio properties
   • No peak amplitude calculation
   • No dynamic range analysis

5. Spectrum Analysis (spectrum.go)

   • No FFT analysis
   • No frequency spectrum visualization
   • No audio visualization data

Simplified Features (Partial Implementation)

6. Metadata Handling (metadata.go)

   • FLAC-only support (no MP3/M4A)
   • No ID3v2 tag support
   • No parallel ISRC checking
   • Simplified duplicate detection

7. Filename Generation (filename.go)

   • No emoji filtering
   • No UTF-8 validation
   • No folder path sanitization
   • Basic character replacement only

8. Downloader Implementations

   • Simplified rate limiting (uses global limiter)
   • Simplified error handling
   • Reduced API fallback sophistication

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Why These Features Are Missing

Technical Constraints

1. No FFmpeg on Android

   • FFmpeg binary cannot be easily bundled with Flutter app
   • Android doesn't allow arbitrary binary execution like desktop
   • Would require native Android implementation or JNI bindings

2. No Advanced Audio Libraries

   • Complex audio analysis requires specialized libraries
   • FFT implementation would need optimization for mobile
   • Memory constraints on mobile devices

3. Simplified Metadata Handling

   • Android focuses on FLAC (primary download format)
   • MP3/M4A support would require additional libraries
   • ID3v2 parsing adds complexity

Design Decisions

1. Focus on Core Functionality

   • Android port prioritizes downloading over format conversion
   • Lyrics feature deferred for future implementation
   • Audio analysis not essential for basic usage

2. Performance Optimization

   • Simplified filename handling reduces CPU usage
   • Global rate limiter more efficient than per-request tracking
   • Reduced metadata operations for faster downloads

3. Maintainability

   • Fewer dependencies = easier to maintain
   • Simpler code = fewer bugs
   • Focused feature set = clearer scope

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Recommendations for Android Port Enhancement

High Priority (Core Functionality)

1. Implement DASH Remuxing Alternative

   • Use Go's audio libraries to convert M4A to FLAC
   • Or accept M4A output for DASH streams
   • Document this limitation to users

2. Add Lyrics Support

   • Implement LRCLIB integration in Go backend
   • Store lyrics in FLAC metadata
   • Display in Flutter UI

Medium Priority (User Experience)

3. Improve Metadata Handling

   • Add MP3 support if users request it
   • Implement parallel ISRC checking
   • Better error messages

4. Enhanced Filename Generation

   • Add emoji filtering
   • Implement UTF-8 validation
   • Support folder path sanitization

Low Priority (Advanced Features)

5. Audio Analysis

   • Implement basic audio properties extraction
   • Calculate peak amplitude and RMS
   • Display audio quality information

6. Spectrum Analysis

   • Implement FFT for visualization
   • Show frequency spectrum in UI
   • Optional feature for advanced users

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Conclusion

The Android port now implements nearly all features of the PC version:

✅ Full Feature Parity:

• Format conversion (FLAC → MP3/M4A) via FFmpeg Kit Flutter
• Lyrics support with LRCLIB integration
• DASH remuxing for Tidal Hi-Res streams
• Full metadata handling including lyrics embedding

⚠️ Not Implemented (Non-Critical):

• Audio analysis (spectrum, peak amplitude, dynamic range)
• These are visualization features, not essential for downloading

Architecture:

• Go backend: Core downloading, metadata, lyrics fetching
• Flutter (FFmpeg Kit): Format conversion, DASH remuxing
• Platform channel: Bridge between Go and Flutter

The port is now suitable for users who want the full SpotiFLAC experience on Android, with all critical features available.