Sobre os arquivos AAC

Áudio AAC

Lançado em 1997 Por MPEG (Fraunhofer, Dolby, AT&T, Sony, Nokia)

AAC (Advanced Audio Coding) é o sucessor técnico do MP3, padronizado em 1997. Apple o adotou para iTunes em 2003 e desde então é o formato de áudio padrão do ecossistema Apple. Tecnicamente superior ao MP3: ~25% melhor compressão a qualidade equivalente. Suporta áudio multicanal (5.1, 7.1) e tem suporte amplo em dispositivos modernos.

Família

Audio Files

Extensão

.aac

Tipo MIME

audio/aac

Pode ser usado como

Entrada Saída

A história

COMO NASCEU O
FORMATO AAC.

1997

2003

AAC — Advanced Audio Coding — was standardized by MPEG in 1997 as the successor to MP3. Fraunhofer led the work again, this time joined by Dolby, AT&T, Sony, and Nokia. The design brief was explicit: at every bitrate, AAC must sound better than MP3. It hit that target across the board.

AAC became mainstream when Apple picked it for the iTunes Store (2003) and later for iPhones. YouTube’s default audio, most digital TV broadcasts in Europe and Asia, and all DAB+ digital radio also use AAC. On mobile it’s ubiquitous because the codec is cheap to decode on low-power hardware. Raw AAC is often stored inside .aac, .m4a, or .mp4 — the file extension tells you about the container, not the codec itself.

CURIOSIDADES E
FATOS INTERESSANTES.

At 128 kbps, AAC sounds roughly equivalent to MP3 at 192 kbps — about 33% smaller for the same quality.

Every iPod, iPhone, and Android phone contains an AAC hardware decoder to save battery.

The HE-AAC variant uses "spectral band replication" to reconstruct high frequencies — a clever trick that keeps low-bitrate audio listenable.

YouTube uses AAC for all audio streams paired with H.264 video, but Opus for its VP9 streams.

Raw AAC (.aac) files use an "ADTS" framing format that makes them trivially streamable — unlike MP4-wrapped M4A.

VANTAGENS E
LIMITAÇÕES.

Vantagens

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.

Limitações

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.

Tamanhos típicos de arquivo

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

Especificações técnicas

MIME type: audio/aac
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

CONVERTER A PARTIR DE
AAC

aac mp3 aac wav aac flac aac m4a aac ogg aac opus aac wma aac aiff aac ac3 aac au aac amr aac aif aac gsm aac voc aac w64 aac sox aac snd aac wv aac spx aac mp2

CONVERTER PARA
AAC

mp3 aac flac aac wav aac alac aac m4a aac ogg aac opus aac wma aac aiff aac ac3 aac au aac caf aac amr aac mka aac ape aac mp4 aac mov aac mkv aac avi aac webm aac flv aac wmv aac mpeg aac 3gp aac ogv aac vob aac m4v aac ts aac m2ts aac mts aac mpg aac aif aac gsm aac voc aac w64 aac shn aac sox aac snd aac 8svx aac tta aac wv aac spx aac mp2 aac dsf aac dff aac swf aac asf aac dv aac f4v aac h264 aac h265 aac m2v aac mjpeg aac mxf aac rm aac rmvb aac divx aac nut aac y4m aac dts aac mid aac ra aac tak aac

Casos de uso comuns

Streaming audio, Apple ecosystem, mobile audio playback.