Ultra Low Bitrates (REALLY!), 22khz Mono at 16kbps Options

[Freya]

I'm encoding at around 16kbps/24kbps in Mono at 22khz. I'm trying to achieve something like FM radio quality.
Sometimes I get close...

I've tried lame VBR with maxbitrate and more recently have tried ABR but I'm not sure the VBR wasn't better?

Does anyone have any tips on how I can improve my encodes in Lame? Should I add a highpass filter? What do others think of ABR vs VBR? I know ABR is recommended for low bitrates...

I know this is really far away from the usual Lame stuff but I hope people might be able to help a bit anyway!

love

Freya

[Fedot L]

I'm trying to achieve something like FM radio quality.
…Does anyone have any tips on how I can improve my encodes in Lame?

To achieve something like FM radio quality, you can code in “mp3 CBR-128 kbps”. Listened to and verified on spectrum analyzer display on music and white noise samples. FM radio frequency band is 30…15000 Hz, “mp3 CBR-128 kbps” frequency band is 30…16000 Hz. If you want to simulate FM radio sound/noise ratio for the best reception conditions too, add hiss at “minus 60 dB” relative to the 0 dB (peak) level of a program listened to.

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…your reply Fedot! Really made me smile…

Really? And your “trying to achieve something like FM radio quality” (and only mono, I don’t know why, as since 1963, FM is stereo…) by coding in “mp3 16 kbps/24 kbps at 22 khz”, when even in “mp3 24 kbps at 22 khz” the frequency band is 8 kHz, and in “mp3 16 kbps at 22 khz” it’s 5,5 kHz (tested and watched on spectrum analyzer display). Against 15 kHz in FM…

…especially the stuff about adding hiss!

You never heard hiss in FM reception?

If it doesn't need to be MP3, you should give OGG Vorbis and AAC a try. These usually work much more efficient at very low bitrates.

You are quite right. “M4a VBR-16 kbps” stereo gave me 10,5 kHz on HQ music/vocal file, with a good stereo effect and rather good general quality. But far from “simulating FM radio quality”.

Best way to beat the swirlies is narrowing the passband that lame has to encode.

I clearly heard that in HQ files coded in “OGG Vorbis” there was no swirling at much lower bitrates than it was present in “mp3”. On some low frequency music passages I heard swirling in “mp3 CBR-128 kbps”, while it was not in “OGG Vorbis CBR-48 kbps”.