Vbr-mp3...

[FSB-SPY]

Is the 'average bitrate' (ABR?) the same as VBR?

I wanted to have exceptional audio and video quality for my movies, so I made my custom file size of 1.3 GBs (I will later take 4 movies and plop them on a DVD CD.) in Gordian Knot and selected 2x VBR-MP3 sound selection. Then I proceed to 'Add Job' and browse to the Audio 1 tab, the only MP3 you could choose is, as noted before, 'average bitrate.' Is there a way to set 128-160, depending on the amount needed? I thought that's what VBR was, if I'm mistaken please educate me. ;)

[cofferscuffs]

Yes as it scales bitrate to get the sound quality good (or something along those lines...). So if you set --abr 128 (the default in Gknot), it will aim to keep at that bitrate unless it's a low noise scene (audio wise that is) and will go as low as 32kbps to save space, but if there's a lot of sound, it will go higher (but not always as high as needed). You can define how high and low it can go by:

-b minbitrate --abr whateveryouwant -B maxbitrate.

However if you want the best ABR sound, download the latest modified Lame which allows for the --dm-preset option and do something like:

--dm-preset 160

To compare with CBR its best to go a few kbps higher when encoding with ABR, so 128 CBR = 133 (roughly) ABR and it will produce roughly the same filsize but better quality.

Just remember to use VBR MP3 audio input in Nandub, not add a wave header to your MP3 file than select WAV otherwise the MP3 won't interleave correctly.

[FSB-SPY]

Thanks for the reply!

Very informative indeed. :) You mentioned getting the latest LAME encoder, that it comes with this new 'dm' switch, what does it exactly do?

All I found mentioned about it in their revision history was this:
LAME 3.90alpha (CVS)
Darin Morrison: some very good VBR and ABR presets, now available with --dm-preset {standard,xtreme,insane,metal}
So what will -dm 160 achieve? And do you suggest doing this apart from setting the min (128) and max (160) VBR? I guess the real question here is, will it yield better results than me simply putting in 160 (128 being the default as you said) into Gordian Knot's ABR MP3 encode setting.

And you mentioned Nandub? I don't believe I use this manually, I just use Godian Knot (Smart Ripper, DVD2AVI, and then encode) and it seems to combine the video and audio on its own.

[cofferscuffs]

the --dm-preset invokes ABR at the bitrate present with a few optimisations like lowpass filters and stuff. Basically it's the best you can get for that bitrate ABR atm.

You don't have to use 160 bitrate, that was just an example and I use it for 1 CD rips and as you are doing 2, you can experiment to get the one that fills two CD's (sometimes for this I use --r3mix full VBR (average achived bitrate ~192).

For Gknot do the MP3 first in Lame (get RazarLame for this a GUI for Lame), then if it fills the size you want do a mux under audio processing.

[FSB-SPY]

Yeah I know I don't have to use 160, but it just happens that I was already. :) I wanted 128-160 VBR, but I guess ABR is better with the use of the--dm switch.

Another question for you, as far as encoding goes, should I encode manually and use some sort of filters for my DVD rips? Or is using GK's automatic process pretty much have me set?


Edit: You said I should get RazorLame, a GUI frontend as I undertand it, do I really need this? I mean, in GK it lets you do a 'manual' command line input, so me putting in '--dm 160' won't work? (Assuming I update my LAME codec.)

[cofferscuffs]

Sorry I got you muddled up, I use RazorLame so I can see the bitrate distrubution before I start). You don't need it if you just update to the latest Lame version so you just use GKnot's command line input.

Erm.. what else? ABR is VBR pratically and everything else you need is included with Gknot provided you do a full install. How to use it? It will either be obvious or you need to read the guides.

[FSB-SPY]

Good stuff! Thank you for your help. :)

[FSB-SPY]

Doh!

Having a problem with the audio now, has to be the new command line...

LAME:
--dm-preset 160

That's all I should have, right? Or do I append this to what was already there by default?

[cofferscuffs]

Just that nothing else. BTW if the AC3 source is 48hz then the MP3 file Lame creates will be 48hz unless you put as well --resample 44.1 to get 44.1hz frequency sound.

[FSB-SPY]

It didn't work. It would skip LAME's encoding and go onto the first pass for video. Something is wrong with that command line, "--dm 160."

[Maccara]

You wrote that you used --dm 160. Use --dm-preset 160 as you have mentioned in your previous post, the word "preset" is part of the switch and should not be left out.

And make sure you have a version of LAME that supports dm-presets. (I suspect that the one coming with GKnot does not?) I know that 3.90 alpha supports.

Also, make sure you have copied the new lame executable over the one in GKnot installation.

Also, please note that this is alpha software and if something goes wrong you're basically on your own.

I haven't had any problems with it myself yet, but then again, I'm constantly previewing the latest and greates, whether it works or not... ;)

B Rgds,
Maccara

[FSB-SPY]

Oops, it was a typo. ;) I did indeed use the said '--dm-preset 160' setting, and it still puked. And yes, I did replace the LAME executable with the latest 3.90 alpha that I found on a site. :(

It's okay though I suppose, I went along last night with: -b 128 --abr 160 -B 192 and it sounds splendid! ;)