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Old Mar 19, 2012, 03:28 PM
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Efendija Efendija is offline
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Quote:
Originally Posted by Hellacia View Post
Slightly off the original topic now (forgive me), but I just wanted to clarify something: in the most recent stable build of LAME, 3.99 (excluding betas and whatnot), when encoding with VBR V -0, the lowpass filter is disabled, right? I encode with LAME 3.99 and I use to do 320kbps, and got a message about the lowpass filter working at about 20.5 KHz, like you said. However, now I use VBR -V 0, and I get a message saying the lowpass filter was disabled.
Yeah, VBR V0 is my favorite for mp3 encoding and I did try 3.99 stable and I think 3.98 is still better for V0... Here are some screens with my comments along:

(Source was lossless of course, view is zoomed on the same spot)





Upper image is CBR 320 kbps with Lame 3.98, and the one below is the same only with 3.99.... Lowpass is still 20.5 kHz for both, but it seems some more information from higher frequency range is kept in 3.99.

Mediainfo details:

Audio
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Mode : Joint stereo
Mode extension : MS Stereo
Duration : 3mn 9s
Bit rate mode : Constant
Bit rate : 320 Kbps
Channel(s) : 2 channels
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 7.21 MiB (100%)
Writing library : LAME3.98r
Encoding settings : -m j -V 4 -q 3 -lowpass 20.5

Audio
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Mode : Joint stereo
Mode extension : MS Stereo
Duration : 3mn 9s
Bit rate mode : Constant
Bit rate : 320 Kbps
Channel(s) : 2 channels
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 7.21 MiB (100%)
Writing library : LAME3.99r
Encoding settings : -m j -V 4 -q 3 -lowpass 20.5





These two images are V0 (upper lame 3.98, lower 3.99). In this new version lowpass filter is disabled or set at 22.1 kHz, which is the same thing, at least for source material with 44.1 kHz freq. This is bad because part of very high frequency sound data is preserved, while the data with a bit lower frequency is lost more in 3.99 than 3.98. I think like this because of the nature of normal human hearing range which is (biological maximum) 20 kHz (per channel). Higher frequencies human ear just can't register at all. Take note that 20 kHz range is if you have really, really perfect hearing, but most people around 30 years old or younger have even lower range (about 18-19 kHz). Back to this, it means new 3.99 V0 keeps some more data above the audible range, while it sacrifices more data on lower (audible) frequencies. On the other hand V0 with 3.98 has lowpass at 19.5 kHz, cutting everything above (which anyway you just can't hear), but keeps more data from 16 kHz to 19.5 kHz range which is more important.

Or to put V0 encode spectral views side by side - left 3.98, right 3.99; it's noticeable 3.99 loses more data in 16-19.5 kHz range... (I've marked it with those green lines lol)



That's why I keep doing mp3 v0 encodes with 3.98, for now. Thanks Hellacia if you had the patience to read this lmao

Mediainfo for V0 encodes:

Audio
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Mode : Joint stereo
Mode extension : MS Stereo
Duration : 3mn 9s
Bit rate mode : Variable
Bit rate : 294 Kbps
Minimum bit rate : 32.0 Kbps
Channel(s) : 2 channels
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 6.64 MiB (100%)
Writing library : LAME3.98r
Encoding settings : -m j -V 0 -q 0 -lowpass 19.5 --vbr-new -b 32

Audio
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Mode : Joint stereo
Mode extension : MS Stereo
Duration : 3mn 9s
Bit rate mode : Variable
Bit rate : 284 Kbps
Minimum bit rate : 32.0 Kbps
Channel(s) : 2 channels
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 6.40 MiB (100%)
Writing library : LAME3.99r
Encoding settings : -m j -V 0 -q 0 -lowpass 22.1 --vbr-new -b 32

Last edited by Efendija; Mar 19, 2012 at 04:18 PM.
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