Ogg Vorbis lower limit - rationale for?

[JimmyBarnes]

With mp3, 128 kbps is the lower limit for no audible loss of quality, though for 1 CD rips, 96 kbps is often used.

With OV, I have often heard 64 kbps recommended as the absolute lower limit - but on what basis? Is there audible loss of quality at this level?

thanx
JB

[MaTTeR]

80-96kbps is the lowest I ever go with Vorbis. Even that might be low if your looking for a surround downmix. If surround is desired at those low bitrates then I might suggest you try lossless or light lossy channel coupling in order to preserve the surround FX.

I would think anything below 80kbps is going to show some artifacts unless the movie has no dynamic sound.

[JimmyBarnes]

Originally posted by MaTTeR
80-96kbps is the lowest I ever go with Vorbis. Even that might be low if your looking for a surround downmix. If surround is desired at those low bitrates then I might suggest you try lossless or light lossy channel coupling in order to preserve the surround FX.

I would think anything below 80kbps is going to show some artifacts unless the movie has no dynamic sound.

What about if using just plain stereo, not surround?

JB

[MaTTeR]

I'm a bit of a quality freak so I most likely would never go under 80kbps, that should work for most movies. For action type movies I'd try -q3 or -q4 possibly.

If your just watching your movies on a computer speaker system then most likely you wont hear any artifacts anyways.

[soujir0u]

At 64kbps Ogg isn't any better than WMA or MP3Pro, I would suggest you never go below 80kbps. Q4.99 gives about 128kbps and sounds pretty good. I'll use that for most movies.

[canadian_fbi]

"loss of quality" is a very subjective term... it depends on what you're encoding and what speakers you're listening to it on and who's listening to it. if a movie is mainly dialogue, then you can get away with low -q values. i personally use 4.99 though, as i notice problems in music in the movie at anything lower than this. it always gives a bitrate under 128, so i don't find it excessive at all.

and i would take issue with your assertion that 128 kbps is the lower limit for no audible loss of quality in mp3s. :) although i'm pretty picky. but still i use 64 kbps mono mp3s for my iron chef encodes, in order to save space, because of the issues with mono vorbis sound and because it's a lot easier.

[Apfelstruhdl]

for 1 cd rips i use vorbis ( headac3he ) at bitrates between 70 and 80 and i am ver impressed by the quality as i can't hear artifacts or very rarely.

i did once a small test and encoded a short sound clip at a really low bitrate. vorbis and lame at arround 40kbs. mp3 was really bad but vorbis was a lot of better ( still very shitty) but 2 or more times better. So i wouldn't use mp3 under 100 kbs and vorbis never under 70 kbs.

but do some testing yourself.;)

Apfelstruhdl

[RadicalEd]

I've done a bunch of tests with all kinds of audio codecs and at all kinds of bitrates, and I'd have to say that the optimum bitrates for the main codecs around today are;
128 mp3
128 wma
128 aac
96 vorbis
64 ra

With mp3, lower than 128 starts to sound as if your ears are plugged with wax.

WMA under 128 starts to show that clinking metallic artifacting which is common to aac and vorbis as well.

AAC is as bad as WMA under 128.

Vorbis at 96 is good, but at 64 the metallic clinking is very apparent, and at 32 it sounds like mp3, again, like your ears are plugged up.

Real Audio amazes me, 64 kbps stereo audio is artifact free and very hard to distinguish from an original uncompressed source. Even 44 is good but the compression begins to show at this bitrate. Unfortunately in this case Real is moot, since its a closed format and you can't use it with your .. eh.. wait a minute.. you can use real audio with a DivX or XviD movie :eek: ah, it just hit me! Scripting an smil that joins the divx/xvid avi with the real audio allows use of realaudio to be coupled with divx ^.^ I wonder if anyone has attempted this yet... well, I have something new to try.

Anyway, quality is of course subjective but I do have pretty good ears and I am a bit of a perfectionist, so don't take those results too lightly ;)