[jack963]

Hey, I had a thread called "MP3 Encoder," in which I aksed many questions, but after fooling around a bit with Lame, I've figured some things out. I now have a more specific question, so I wanted to start a new thread.

Anyways, I'm using CDex and Lame, and there are two fields that still mystify me: Bitrate Min and Bitrate Max. So far, I've just set them both to the same value: 160 kbps. Is it not a good idea to do so? Should there be a range? Say, 128 for Min. and 192 for Max?

Also, I've been encoding with the following settings:

Bitrate Min: 160
Bitrate Max: 160
Quality: Very High Quality (q=0)
VBR Method: VBR-new
VBR Quality: 0

Do you see anything wrong with these settings?

Also, for "Mode," there is "Stereo" and "J-stereo." What's the difference?

Thanks for the help.

 

[Outlaws]

i think by setting both at same range, the bit rate will be constant not variable
and about stereo , joint stereo, that may help:
copied:
· Joint Stereo: Joint Stereo shares certain bits between high frequency left and right channels. This improves compression efficiency at a slight loss of stereo separation. Lower frequencies are treated as normal stereo. Use Joint Stereo to obtain the best overall quality at mid-to-lower bit rates. < 224 Kbit.

· Stereo: Stereo includes two independent channels. The total bit rate remains constant, but the split between the channels can vary. The Encoder uses this flexibility to improve quality by allocating more bits to the channel with the more dynamic signal. Use the Stereo setting for best quality stereo audio at higher bit rates.

 

[jack963]

Thanks a lot. So, is there some sort of guideline as to how to set the bitrate min/max range? My target bitrate is 160 kbps; should the min be one step below 160 (128) and the max be one step above 160 (192)? Thanks again.

 

[jack963]

Sorry to double post, but looking back at a link a member referred me to, why do I even have to set the bitrate min/max at all? Am I doing something wrong? Looking at this page, http://www.hydrogenaudio.org/forums/...howtopic=28124, it looks like all I should have to do is set it at "VBR-new," "VBR Quality 0," and that is it. It doesn't mention "Quality" (not too be confused with "VBR Quality"), nor the bitrate min./max. setting. Can somebody who uses Lame please clarify this for me? Thanks.

 

[Asr]

There are two types of MP3 files: CBR (Constant Bit Rate) and VBR (Variable Bit Rate).

CBR is when you set the min and max to the same value, and the encoder will encode the entirety of the source WAV file at that one bit rate. This keeps the sound all at an equivalent bit rate, which is helpful in some situations.

When you set the min and max to different values, you're about to make a VBR MP3. What VBR does is encode the source WAV at varying bit rates (the minimum and maximum of which you set) as it encodes, using lower bit rates on less complicated passages, and higher bit rates on complex passages. The overall effect hopefully isn't noticeable, and usually results in smaller file sizes than CBR.

Back when MP3 was new most playback software and hardware players didn't support VBR, but now you won't find anything that doesn't support it. So it's a trade-off, VBR tends to give smaller file sizes but an unknown bit rate "gradient" in the MP3, while CBR encodes everything at the same rate so you can be assured of whatever quality level you want, but leads to higher file sizes. CBR is still economical though as long as you don't go past 256 kb/s. 128 kb/s gives about 1 MB per minute, 160 kb/s gives about 1.5MB per minute, 192 kb/s just under 2MB per minute. 192 kb/s is generally regarded to be the best balance of file size vs sound quality for CBR.

 

[jack963]

Ok, thanks a lot for the info.