Convert MPEG Audio Layer 1 (.mp1) to MPEG-4 Audio (.m4a) online for free. Fast, secure audio conversion with no watermarks or registration.
Upload your .mp1 file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .m4a file when it's ready.
Converting MP1 to M4A upgrades legacy MPEG Audio Layer 1 content to the modern MPEG-4 audio container with AAC or ALAC encoding. M4A is the default audio format across Apple's ecosystem and is widely supported on Android, Windows, and web browsers. This conversion transforms audio from the earliest perceptual coding standard to its most modern successor.
MP1 was standardized in 1993 as part of MPEG-1 (ISO 11172-3). M4A/AAC was standardized in 1997 as part of MPEG-2 and enhanced in MPEG-4. The 30+ year evolution between these formats brought dramatic improvements in compression efficiency and metadata support.
M4A provides everything MP1 lacks: universal device support, rich metadata (artist, album, artwork, lyrics, chapters), efficient compression, and integration with modern music ecosystems. Converting MP1 to M4A is the definitive format upgrade — the resulting file plays everywhere, looks good in media libraries, and uses storage efficiently.
For music library organization, M4A's extensive metadata support transforms tagged, categorized audio from anonymous MP1 bitstreams. Adding proper metadata during conversion creates a usable, organized library from previously unmanageable MP1 collections.
FFmpeg decodes the MP1 subband audio to PCM and encodes to AAC-LC within an M4A (MPEG-4 Part 14) container. The M4A container supports moov, udta, and ilst atoms for comprehensive metadata. For archival, ALAC encoding within M4A preserves the decoded audio losslessly. VBR mode optimizes bitrate allocation per frame. The encoder handles the full encoding pipeline internally.
AAC at 128-192 kbps in M4A preserves the full quality of most MP1 sources — the AAC codec can represent all the audio information the MP1 decoder produces. At 256 kbps, the output exceeds the MP1 source quality ceiling. ALAC in M4A provides lossless decoded quality.
| Device | MP1 | M4A |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Native |
| iPhone/iPad | Partial | Native |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No |
Resolution: N/A
Bitrate: 320 kbps
OGG Vorbis preferred
Resolution: N/A
Bitrate: 256 kbps
AAC format required
Resolution: N/A
Bitrate: 128 kbps
Lossless FLAC/WAV for best quality
Resolution: N/A
Bitrate: 128 kbps
MP3 mono for spoken word
MP1 to M4A is the definitive format modernization for legacy MPEG audio. M4A provides universal playback, rich metadata, and efficient compression.
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| No |
| ฟีเจอร์ | MP1 | M4A |
|---|---|---|
| ชื่อเต็ม | MPEG Audio Layer 1 | MPEG-4 Audio |
| นามสกุล | .mp1 | .m4a |
| เหมาะที่สุดสำหรับ | Early MPEG standard | Better than MP3 |