Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: technical merits of formats (encoding) (Read 4452 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

technical merits of formats (encoding)

What additional encoding strategies does AAC use that make it technically (not necessarily implementation/compatibility) superior to mp3? I always here this as a reason for why AAC is marginally better, but what exactly are these additional encoding techniques?

Can someone point me to a technical document/site that explains this?

technical merits of formats (encoding)

Reply #1 –
Quote
What additional encoding strategies does AAC use that make it technically (not necessarily implementation/compatibility) superior to mp3? I always here this as a reason for why AAC is marginally better, but what exactly are these additional encoding techniques?

Can someone point me to a technical document/site that explains this?
[a href="index.php?act=findpost&pid=349299"][{POST_SNAPBACK}][/a]

There are several limitations inherent to the MP3 format that cannot be overcome by using a better encoder.

Newer audio compression formats such as Vorbis and AAC no longer have these limitations.

In technical terms, MP3 is limited in the following ways:
Bitrate is limited to a maximum of 320 kibit/s
Time resolution can be too low for highly transient signals
No scale factor band for frequencies above 15.5/15.8 kHz
Joint stereo is done on a frame-to-frame basis
Encoder/decoder overall delay is not defined, which means lack of official provision for gapless playback; gaps may be introduced between tracks, although this can be avoided to a degree by using LAME to encode.

Nevertheless, a well-tuned MP3 encoder can perform competitively even with these restrictions. [wikipedia]

technical merits of formats (encoding)

Reply #2 –
Quote
What additional encoding strategies does AAC use that make it technically (not necessarily implementation/compatibility) superior to mp3? I always here this as a reason for why AAC is marginally better, but what exactly are these additional encoding techniques?

Can someone point me to a technical document/site that explains this?


These are some of the more interesting ones from a technical perspective.

PNS - Perceptual Noise Substitution
TNS - Temporary Noise Shaping
SBR - Spectral Band Replication
LTP - long Term Prediction

http://www.audiocoding.com/modules/wiki/?p...+Technical+Info here you go. Have a field day  . The scale factor band 21 issue has always pissed me off with MP3 though. If something was encoded with LAME, however I wouldn't be as bitter about it.
budding I.T professional
 

technical merits of formats (encoding)

Reply #4 –
Quote
SBR - Spectral Band Replication
LTP - long Term Prediction
[a href="index.php?act=findpost&pid=349341"][{POST_SNAPBACK}][/a]


SBR can be applied to MP3 too (MP3Pro) and LTP is never used. So these don't count.