AAC vs SPX
Ein detaillierter Vergleich von AAC Audio und Speex Audio — Dateigröße, Qualität, Kompatibilität und welches je nach Workflow zu wählen ist.
AAC Audio
Audio FilesAAC is a lossy audio codec that delivers better sound quality than MP3 at similar bitrates. It is the default audio format for Apple Music, YouTube, and most streaming services.
Über AAC-DateienSpeex Audio
Audio FilesSpeex is an open-source audio compression format specifically designed for speech encoding. It uses Code-Excited Linear Prediction (CELP) and supports narrowband, wideband, and ultra-wideband modes for different speech quality requirements.
Über SPX-DateienVorteilsvergleich
AAC Vorteile
- Better quality than MP3 at equal bitrate — the industry standard since 2000s.
- Universally supported on every smartphone, OS, and browser.
- Efficient on battery thanks to widespread hardware decoding.
- Scales from 8 kbps speech (HE-AACv2) to lossy-transparent 320 kbps.
- Five-channel + LFE surround support out of the box.
SPX Vorteile
- Patent-free voice codec.
- Three sample-rate modes for voice.
- Low CPU decode.
Einschränkungen
AAC Einschränkungen
- Patent-encumbered — encoders have licensing fees, which is why open alternatives (Opus, Vorbis) exist.
- Slightly more complex to encode than MP3.
- Raw .aac streams carry no seek index — tooling often prefers M4A/MP4 containers.
- Lossy — not suitable for archival or studio production.
SPX Einschränkungen
- Deprecated in favor of Opus.
- No music support.
- Rarely used in new projects.
Technische Spezifikationen
| Spezifikation | AAC | SPX |
|---|---|---|
| MIME type | audio/aac | audio/speex |
| Extensions | .aac, .m4a, .mp4 (container-dependent) | — |
| Standard | ISO/IEC 14496-3 | — |
| Variants | AAC-LC, HE-AAC, HE-AACv2, AAC-LD, xHE-AAC | — |
| Sample rates | 8-96 kHz | — |
| Extension | — | .spx |
| Container | — | Ogg |
| Modes | — | Narrowband/Wideband/Ultra-wideband |
| Successor | — | Opus |
Typische Dateigrößen
AAC
- Speech podcast (64 kbps) 1 MB/min
- 3-min music track (128 kbps) 3 MB
- 3-min music track (256 kbps) 6 MB
- Broadcast-quality 5.1 (384 kbps) 9 MB for 3 min
SPX
- 1 min voice (wideband 24 kbps) ~180 KB
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Häufig gestellte Fragen
AAC (Advanced Audio Coding) is a lossy audio format standardized by ISO as the successor to MP3. It delivers better sound quality than MP3 at equivalent bitrates and is the default audio format for Apple products, YouTube, and most streaming services.
AAC (Advanced Audio Coding) is a com perdas audio formato padrãoized by ISO como o successor to MP3. It delivers better sound quality than MP3 at equivalent bitrates e is the default audio formato para Apple products, YouTube, e most streaming services.
AAC files play in iTunes, Apple Music, VLC, Windows Media Player, and all modern web browsers. AAC is natively supported on iOS, Android, macOS, and Windows.
AAC arquivos reproduzir in iTunes, Apple Music, VLC, Windows Media Player, e all moderno web browsers. AAC is natively suportado no iOS, Android, macOS, e Windows.
AAC is technically superior, offering better quality at the same bitrate. Use AAC for Apple ecosystem and modern devices. Use MP3 only when you need compatibility with very old hardware like legacy car stereos or basic MP3 players.
AAC is technically superior, offering better quality at the same bitrate. usar AAC para Apple ecosystem e dispositivos modernoos. usar MP3 only when you need compatibilidade com very old hardware like legacy car stereos ou basic MP3 players.