Re: Converting FLAC to Opus. 160 or 192kbps for universal transparency?
Reply #8 – 2021-05-13 11:16:27
160kbps would be my upper limit for any post MP3 codec, Any higher like 192 ~ 320kbps may as well use Lossless codec. Outside of few hard samples on MP3, LAME V5 ~ V4 still hold up very well for many people. Yeah, I would largely agree, especially taking efficiency into account. even for MP3 using the Hydrogenaudio Wiki page (i.e. https://wiki.hydrogenaud.io/index.php/LAME#Recommended_encoder_settings ) as a guide... given what it says there I tend to figure V4 (165kbps average) is probably not worth using considering there is only 10kbps difference going to V3 (175kbps average) which is the early stage of 'very high quality' mode where as V4 is still a bit shy of that status and is barely lower in bit rate. that's why when it comes to MP3 I tend to be of the mindset to use either V5 (130kbps average) or switch to at least V3 (175kbps average). even V2 (190kbps) probably ain't a bad idea either since it's only minimally more bit rate than V3. but I have no idea whether V3 (175kbps average) to V2 (190kbps average) has much, if any, real world difference in sound quality(?). but some might just see it as a little safety buffer. but once you start getting into V1(225kbps) or V0(245kbps), MP3's efficiency starts to go out the window. NOTE: even for those who like to nit pick over fine tuning MP3's bit rates may consider one users suggestion of V1.7 which I think floats around 200kbps off the top of my head. but yeah, I think V5 is pretty good for myself and is still quite efficient to. I tend to see V5 (130kbps average) as a good minimum bitrate guideline when it comes to MP3 and, like you said, holds up well for many people, especially given this public listening test from 2014 (i.e. https://listening-test.coresv.net/results.htm ) which pretty much sums up that MP3 V5 is a solid performer all-around even though I am sure there are some who claim one needs V0(245kbps average) or 320kbps for MP3 to be good which is largely not true given the data we got to say otherwise, especially for anyone who's anywhere near the average person. so given this whole V5 (130kbps average) with MP3 doing pretty well for many, that's kind of why I think with Opus many (hell, I think it's safe to say most people) will be okay with 64kbps or no more than 96kbps, since as you already know, 96kbps is better than MP3 @ V5 (130kbps average) and will probably challenge the higher bit rate MP3 ranges. I think it was IgorC that said Opus @ 80kbps is roughly the same as MP3 @ V5 (130kbps average). hell, I don't think it's a stretch to claim that Opus @ 64kbps could challenge MP3 @ V5 (130kbps average) for many people (since many people tend not to be able to hear the finer details that people like IgorC etc can around here) and it's about half the bit rate. even with your post-MP3 encoder comment of 160kbps being upper limit... I doubt I can tell a difference between Opus @ 96kbps and maybe not even at 64kbps in most cases. so, at least speaking for myself, I almost surely won't even need to be close to 160kbps to have WELL more than enough quality sound (although I get your reasoning taking into account a bit more picky listeners in which case I can easily see you arguing 160kbps is the sweet spot for those types of people). when I think Opus I tend to have the mindset 'use 96kbps and forget about it' as a general guideline as that will likely please a lot of people short of a small amount of golden eared types. but if someone is a bit tight on space, 'use 64kbps and forget about it'. NOTE: I tend to consider 64kbps a good minimum for Opus as going lower than that, while still respectable sound quality given the bit rates, it's not worth the largely minimal storage space savings for the sound quality decline at that point and I also feel basically the same in another way when it comes to 96kbps in that going higher than that point one is not increasing sound quality enough to justify 1/4th or more bit rate increase (i.e. like say 96kbps to 128kbps or higher). but then I am sure, especially at this point in time when storage space is cheap, one could argue it does not even matter (i.e. jack up the bit rate (say 192kbps+) and forget about it). still, I think, as you basically think, that the whole point of lossy is to find that sweet spot of sound quality/storage space as it defeats the purpose of using lossy files with ridiculously high bit rates (i.e. lets call 'ridiculously high' over about 192kbps or so), especially with modern encoders like Opus which can really drop bit rates (i.e. 64kbps) without sound quality taking too much of a hit for the common person or thereabouts.