Hi there,
a friend sold me his old MP3-standard-player for 1 EUR (aprox $1.5).
It plays MP3 only ... no SVCD, no DVD ... funny :-)
It makes trouble with VBR-MP3s produced by LAME :-(
Is it okay to use the "--alt-preset cbr 192" setting for reencoding the MP3s from "--alt-preset standard" to CBR?
Or is there a better setting?
Best,
Tobias
Full Version: Reencoding VBR => CBR
Well if you can still get hold of the originals then your are best off to re-rip, but if you currently only have the VBR mp3's then you've got no choice but to transcode.
The only thing I could think of that might be worth a try would be to re-encode it without any lowpass filter (there are command line parameters to do this but I've never used them as they're not normally recommended). So I haven't tested this but it just crossed my mind that it might be worth a try becuse the original material has (presumably) already been LPF'ed once during the original VBR encoding.
Has anyone here ever tested this "no LPF" idea for trancoding when the source mp3 has already been suitibly LPF'ed for the target bit rate ?
The only thing I could think of that might be worth a try would be to re-encode it without any lowpass filter (there are command line parameters to do this but I've never used them as they're not normally recommended). So I haven't tested this but it just crossed my mind that it might be worth a try becuse the original material has (presumably) already been LPF'ed once during the original VBR encoding.
Has anyone here ever tested this "no LPF" idea for trancoding when the source mp3 has already been suitibly LPF'ed for the target bit rate ?
mmh, why no LPF? AFAIK vbr uses LPF also.
So double-low-pass won't chance anything, since first low-pass removed the things already :-)
So double-low-pass won't chance anything, since first low-pass removed the things already :-)
QUOTE(TobWen @ Jan 11 2005, 04:38 AM)
mmh, why no LPF? AFAIK vbr uses LPF also.
So double-low-pass won't chance anything, since first low-pass removed the things already :-)
So double-low-pass won't chance anything, since first low-pass removed the things already :-)
Not true. It would be true if the LPF was ideal (or perfect) but for real filters the resultant response of "double filtering" can be significantly different. That's why I suggested it might be worth a try.
can I override --alt-preset cbr 's lowpass directly or do I have to enter the "real" commands?
-k (I think)
But note that there is no proof that this would be any better. Since you are transcoding to a different preset than what the original is in (-aps) this preset may have a different lowpass than -aps. Each preset has a lowpass that should be optimum for that specific preset. By overriding this lowpass with -k you will be using -aps lowpass with a different preset. This seems bad to me generally.
For your specific example of transcoding to -ap cbr 192, I think actually that this preset has a slightly higher lowpass than -aps so there shouldn't really be any practical difference (whether you use -k or not).
I think you would improve much more by raising the bitrate from 192 to as high as your portable is capable of handling. It may be that it cannot handle 320 kbps, and therefore cannot handle -aps encodings. If that is the case you have to stay at 256 kbps.
But note that there is no proof that this would be any better. Since you are transcoding to a different preset than what the original is in (-aps) this preset may have a different lowpass than -aps. Each preset has a lowpass that should be optimum for that specific preset. By overriding this lowpass with -k you will be using -aps lowpass with a different preset. This seems bad to me generally.
For your specific example of transcoding to -ap cbr 192, I think actually that this preset has a slightly higher lowpass than -aps so there shouldn't really be any practical difference (whether you use -k or not).
I think you would improve much more by raising the bitrate from 192 to as high as your portable is capable of handling. It may be that it cannot handle 320 kbps, and therefore cannot handle -aps encodings. If that is the case you have to stay at 256 kbps.
Hi, it's not a portable. It's a hifi-thing ... but okay, I will play around with the settings. Thanks!
--alt-preset standard has a lower transition band (18671 Hz - 19205 Hz) than CBR 192; all ABR/CBR bitrates from 176-207 use the transition band 19383 Hz - 19916 Hz. Doesn't this mean that --alt-preset standard removes everything above 19205 Hz so there would be no effect from reencoding with a transition band that starts at 19383 Hz?
I would assume that disabling the lowpass for bitrates of 176 or higher is therefore irrelevant. If that's not the case, I could certainly understand disabling the filter since the initial encoding has already done more filtering than normal for CBR 192.
I would assume that disabling the lowpass for bitrates of 176 or higher is therefore irrelevant. If that's not the case, I could certainly understand disabling the filter since the initial encoding has already done more filtering than normal for CBR 192.
QUOTE
Hi there,
a friend sold me his old MP3-standard-player for 1 EUR (aprox $1.5).
It plays MP3 only ... no SVCD, no DVD ... funny :-)
a friend sold me his old MP3-standard-player for 1 EUR (aprox $1.5).
It plays MP3 only ... no SVCD, no DVD ... funny :-)
Get yourself a new player for chrissake!
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.