HydrogenAudio

Hosted Forums => foobar2000 => General - (fb2k) => Topic started by: gfxnow on 2018-11-06 11:35:09

Title: Bits per sample conversion
Post by: gfxnow on 2018-11-06 11:35:09
Some of the music that I have gotten from Bandcamp is oddly 24/44.1 FLAC.

Normally the high-res music that I get is 24/48 or 24/96. When converting those to mp3 I use the SSRC dsp and choose 44.1 in the options. That gives me properly dithered 16/44.1 mp3 files.

How should I handle 24/44.1 FLAC to mp3 conversion for optimum quality? Thank you
Title: Re: Bits per sample conversion
Post by: Case on 2018-11-06 14:01:15
MP3 has no bit depth and there's no reason to add dither noise or lower the bit depth before encoding. LAME is able to use the 24-bit source signal as is. Only thing you can and should do is resample unsupported sample rates to 44.1 kHz as you have done.
Title: Re: Bits per sample conversion
Post by: yetanotherid on 2018-11-08 22:43:30
LAME supports 48k, so wouldn't it be better to resample 96k source files to 48k rather than 44.1k and leave 48k source files as-is?
48k support appears to be part of the MP3 specification so a compliant player shouldn't have a problem with them. https://en.wikipedia.org/wiki/MP3#Bit_rate

My portable MP3 player, which is probably 8-9 years old, happily plays 48k MP3s (a long time ago, I resampled some 48k sources to 44.1k myself before I realised it wasn't necessary). Back when everybody was encoding their DVDs as Xvid/MP3/AVI, the audio was converted to mp3 without resampling to 44.1k and I've never met a player that was unhappy about it.

The SSRC DSP will resample from 96k to 48k etc but it doesn't change the bitdepth from 24 to 16.
Title: Re: Bits per sample conversion
Post by: Case on 2018-11-09 07:45:53
At least historically LAME provided better quality at 44.1 kHz than with 48 kHz. It's a myth that resampling to integer multiples provides better quality.
Title: Re: Bits per sample conversion
Post by: yetanotherid on 2018-11-12 04:33:34
I wonder why LAME would provide better quality at 44.1kHz. I'm not saying you're wrong or anything... just wondering why.
Cheers.
Title: Re: Bits per sample conversion
Post by: magicgoose on 2018-11-12 07:19:11
I wonder why LAME would provide better quality at 44.1kHz. I'm not saying you're wrong or anything... just wondering why.
Cheers.
Could be that this was the most common format (CDDA) so it was the target for most optimizations.
Title: Re: Bits per sample conversion
Post by: gfxnow on 2018-11-13 16:59:25
MP3 has no bit depth and there's no reason to add dither noise or lower the bit depth before encoding.
Thank you!

48k support appears to be part of the MP3 specification so a compliant player shouldn't have a problem with them

Interesting. Did not know that. Thanks!