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Old 2012-05-21, 00:58   Link #40
Quarkboy
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Join Date: Nov 2003
Location: Tokyo, Japan
Age: 44
Quote:
Originally Posted by HauntingShock View Post
What does LC and HE means?
AAC has two different profiles (i.e, modes).

LC = Low Complexity
HE = High Efficiency

Briefly, LC mode is designed for ease of playback, where decoding takes little computing resources (good for things like ipods which have limited battery life)
HE mode is designed for maintaining quality at lower bitrates while sacrificing decoding complexity.

To be more specific, HE adds on something extra to the codec called " spectral band replication ", which is the main way it increases perceived quality at lower bandwidths. Basically, it's a way of recreating high frequency data using the low frequency data: It makes things sound more crisp even at low bitrates.
This recreation however is just that, a replica. It doesn't actually recreate the original high-frequency data, and thus can get in the way at higher bitrates and actually make things sound WORSE than LC (in my opinion).

A practical guide is that you should use LC when you want to maximize playback capability, and whenever your bitrates are more than like, 48 Kb/s (per stereo track). If you're doing something like 192 Kb/s 5.1, HE might give you better quality. Or if you're doing a super low bitrate like 48 Kb/s stereo, then HE is the way to go.
But for most anime encoding LC is the correct choice.

There, that's more information than you need .
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