[FFmpeg-user] 5.1 AAC without lowpass on the LFE channel

[Steven Ruppert]

On 9/12/22 09:33, Steven Ruppert via ffmpeg-user wrote:
> I couldn't find any references whether that's inherent to the AAC 5.1 
> encoding, something that ffmpeg does, or inherent to the decoding 
> process. (I did decode my same test files using something that uses 
> Microsoft MediaFoundation and the LFE channel was still lowpassed).

Turns out the AAC codec inherently limits the LFE bandwidth, so there's 
no way around it.

The actual ISO/IEC 13818-7:2006(en) Standard costs a bunch of money to 
read as usual, but in the free glossary there is an entry:

 >low frequency enhancement ( LFE ) channel: limited bandwidth channel 
for low frequency audio effects in a multichannel system

https://www.iso.org/obp/ui/#iso:std:iso-iec:13818:-7:ed-4:v1:en