Convert MPC to AMR
Max file size 100mb.
MPC vs AMR Format Comparison
| Aspect | MPC (Source Format) | AMR (Target Format) |
|---|---|---|
| Format Overview |
MPC
Musepack / MPEG Plus
Musepack is a lossy audio codec derived from MPEG-1 Layer II, developed by Andree Buschmann in the late 1990s. Optimized for perceptual transparency at high bitrates, it became a reference format for audiophiles seeking the best possible lossy compression. The codec uses quality-based variable bitrate encoding centered around 180 kbps for its standard quality profile. Lossy Legacy |
AMR
Adaptive Multi-Rate
AMR is a speech codec standardized by 3GPP (3rd Generation Partnership Project) for GSM and 3G mobile telephony. Operating at extremely low bitrates (4.75–12.2 kbps), AMR is optimized exclusively for human voice rather than music. It dynamically adapts its bitrate based on network conditions, making it ideal for voice calls, voicemail, and MMS audio messages on mobile networks. Lossy Legacy |
| Technical Specifications |
Sample Rates: 44.1 kHz, 48 kHz, 32 kHz
Bit Rates: ~160–250 kbps VBR typical Channels: Mono, Stereo Codec: Musepack SV7/SV8 Container: .mpc (Musepack stream) |
Sample Rate: 8 kHz (narrowband fixed)
Bit Rates: 4.75, 5.15, 5.90, 6.70, 7.40, 7.95, 10.2, 12.2 kbps Channels: Mono only Codec: AMR-NB (ACELP-based) Container: .amr, or inside 3GP/3G2 |
| Audio Encoding |
Musepack applies enhanced MPEG-1 Layer II psychoacoustics with sub-band coding optimized for music transparency: # Decode MPC to PCM ffmpeg -i input.mpc -codec:a pcm_s16le \ decoded.wav # Musepack targets perceptual quality # rather than specific bitrate targets |
AMR uses Algebraic Code-Excited Linear Prediction (ACELP) optimized for encoding human speech at very low bitrates: # Convert MPC to AMR (12.2 kbps max) ffmpeg -i input.mpc -codec:a libopencore_amrnb \ -ar 8000 -ac 1 -b:a 12.2k output.amr # Lower bitrate for smaller files ffmpeg -i input.mpc -codec:a libopencore_amrnb \ -ar 8000 -ac 1 -b:a 6.7k output.amr |
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| Version History |
Introduced: 1997 (as MPEG Plus)
Current Version: SV8 (Stream Version 8) Status: Legacy — inactive since ~2009 Evolution: MPEG Plus → SV4–SV6 → SV7 (2003) → SV8 (2009) |
Introduced: 1999 (3GPP TS 26.071)
Current Version: AMR-NB, AMR-WB (wideband variant) Status: Legacy — being replaced by EVS codec Evolution: AMR-NB (1999) → AMR-WB (2001) → EVS (2014) |
| Software Support |
Media Players: foobar2000, VLC, AIMP, Winamp
DAWs: Limited — via FFmpeg import Mobile: No native support Web Browsers: Not supported Libraries: libmpcdec, FFmpeg |
Media Players: VLC, QuickTime, Windows Media Player
Mobile: All mobile phones (native) Telephony: Asterisk, FreeSWITCH, Opal Web Browsers: Limited support Libraries: opencore-amr, FFmpeg, vo-amrwbenc |
Why Convert MPC to AMR?
Converting MPC to AMR is a specialized operation for extracting voice content from Musepack audio and preparing it for mobile telephony systems. AMR is the standard voice codec for GSM and 3G mobile networks, producing extremely compact files suitable for voice messages, MMS attachments, and telephony applications. This conversion makes sense only when you need voice-quality audio at the smallest possible file size.
It is important to understand that AMR is a speech-only codec operating at 8 kHz sample rate and mono only. Music content will sound poor in AMR format because the codec's psychoacoustic model is tuned exclusively for human voice frequencies (300–3400 Hz). The conversion is appropriate for spoken-word MPC recordings like voice memos, interviews, or podcast episodes where music quality is not the primary concern.
The primary advantage of AMR is its remarkably small file size. At 12.2 kbps (the highest AMR-NB bitrate), a one-minute recording occupies approximately 90 KB — compared to roughly 1.3 MB for the same duration in MPC. This extreme compression makes AMR ideal for sending audio via MMS messages or storing voice recordings on devices with very limited storage.
For modern voice applications, consider using Opus instead, which offers better quality at similar bitrates with broader software support. AMR conversion is most relevant for legacy mobile systems, specific telephony platforms, or when you need guaranteed compatibility with older mobile phones that only support AMR natively.
Key Benefits of Converting MPC to AMR:
- Tiny Files: Approximately 90 KB per minute at maximum quality
- Mobile Universal: Every mobile phone supports AMR playback
- MMS Ready: Fits within MMS size limits for audio messages
- Voice Optimized: Clear speech reproduction at ultra-low bitrates
- Telephony Standard: Compatible with IVR and voicemail systems
- Low Bandwidth: Suitable for poor network connections
- 3GPP Standard: Official GSM/3G voice format
Practical Examples
Example 1: Extracting Voice Memo for MMS
Scenario: A user has a recorded interview stored as MPC and needs to send a short clip via MMS message to a colleague with a basic phone.
Source: interview_clip.mpc (45 sec, ~180 kbps, 990 KB) Conversion: MPC → AMR (12.2 kbps, 8 kHz, Mono) Result: interview_clip.amr (67 KB) Benefits: ✓ Under 100 KB — fits any MMS size limit ✓ Plays on any mobile phone natively ✓ Voice content remains clearly intelligible ✓ No app installation required for recipient ✓ 93% file size reduction from original
Example 2: Creating IVR System Prompts
Scenario: A business has voice prompts recorded as MPC files that need to be uploaded to their telephony IVR system which requires AMR format.
Source: welcome_message.mpc (15 sec, ~175 kbps, 320 KB) Conversion: MPC → AMR (12.2 kbps, 8 kHz, Mono) Result: welcome_message.amr (22 KB) Telephony integration: ✓ AMR natively supported by Asterisk PBX ✓ Standard format for 3GPP telephony systems ✓ Minimal server storage for prompt libraries ✓ Low bandwidth during playback to callers ✓ Compatible with FreeSWITCH and Opal
Example 3: Archiving Voice Recordings Compactly
Scenario: A journalist has hours of interview recordings stored as MPC and needs an ultra-compact voice archive for limited cloud storage.
Source: full_interview.mpc (90 min, ~185 kbps, 122 MB) Conversion: MPC → AMR (12.2 kbps, 8 kHz, Mono) Result: full_interview.amr (8 MB) Storage savings: ✓ 93% reduction in file size ✓ Voice remains clearly intelligible ✓ Suitable for transcription workflows ✓ Multiple hours fit on basic cloud storage ✓ Playable on any mobile device
Frequently Asked Questions (FAQ)
Q: Will music sound good in AMR format?
A: No — AMR is a speech codec operating at 8 kHz sample rate (telephone bandwidth of 300–3400 Hz). Music will sound heavily degraded, losing all high frequencies, stereo imaging, and musical detail. AMR should only be used for voice/speech content. For music, use AAC, MP3, OGG, or Opus instead.
Q: What is the maximum quality AMR can achieve?
A: AMR-NB (narrowband) maxes out at 12.2 kbps with 8 kHz sample rate — equivalent to standard telephone call quality. AMR-WB (wideband) extends to 23.85 kbps with 16 kHz sample rate for clearer voice. Neither comes close to MPC's audio quality. The conversion involves significant quality reduction by design.
Q: Why would I convert high-quality MPC to low-quality AMR?
A: The only practical reasons are: extreme file size reduction for voice content, compatibility with legacy mobile phones, MMS audio message creation, or telephony system requirements (IVR, voicemail). If your MPC files contain music, AMR is not an appropriate target format.
Q: Is AMR still relevant in modern mobile systems?
A: AMR-NB remains deployed in 2G/3G networks, but it is being phased out in favor of EVS (Enhanced Voice Services) for VoLTE (4G) and VoNR (5G). For new projects, Opus offers better voice quality at similar bitrates with broader software support. AMR conversion is mainly relevant for legacy system compatibility.
Q: Can AMR files be played on desktop computers?
A: Yes — VLC, QuickTime Player (macOS), and Windows Media Player (with codecs) can all play AMR files. Most media players with FFmpeg-based backends handle AMR without issues. However, the audio quality will sound like a telephone call regardless of your playback equipment.
Q: What is the difference between AMR-NB and AMR-WB?
A: AMR-NB (narrowband) operates at 8 kHz with bitrates of 4.75–12.2 kbps — standard telephone quality. AMR-WB (wideband, also called HD Voice) operates at 16 kHz with bitrates up to 23.85 kbps, providing noticeably clearer voice reproduction. Our converter uses AMR-NB by default for maximum compatibility.
Q: How small will the AMR files be compared to MPC?
A: AMR files are dramatically smaller. At 12.2 kbps, AMR produces about 91 KB per minute compared to MPC's ~1.3 MB per minute — roughly 14 times smaller. At lower AMR bitrates (6.7 kbps), the ratio is even more extreme. This compression comes at the cost of music quality, retaining only telephone-grade voice clarity.
Q: Will stereo information be preserved?
A: No — AMR is mono only. The stereo MPC audio will be downmixed to a single mono channel during conversion. Additionally, the sample rate drops from 44.1/48 kHz to 8 kHz, discarding all frequencies above 4 kHz. This is by design — AMR is a narrowband telephone speech codec, not a music format.