Rockbox.org home
release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Rockbox mail archive

Subject: Re: Quick questions
From: Chris Holt (amiga2k_at_cox.net)
Date: 2003-10-20


NO

This is completely wrong. JS utilizes a MS Stereo uses one channel to
encode information that is identical on the left and right channels and
the other channel to encode the differences between the two channels., to
reduce the quantity of information. There is no reason for a MS stereo
encoding technique to sacrifice quality to reduce needed bandwidth because
it can be done without sacrifice.

What you give below is closer to a description of Intensity Stereo
encoding which is only used for Layer2 encoding on low bitrate files where
it only encodes bits that are perceived to be important to the
stereophonic image.

I'm no expert on the MAS chip, but I feel fairly confident that it
shouldn't be doing IS encoding, at least on the higher quality settings.
Surely someone here can expand on this.

Chris

On Mon, 20 Oct 2003 17:31:10 +0100, BlueChip wrote:
> 1. ???
> 2. "Joint Stereo" divides the fequency spectrum in to two halves. Not
> sure quite where the line is, but the theory is that the human ear
> cannot detect direction for frequencies below a certain value.
> SO... The recording is generally stereo, but frequencies below this
> line (not more than 200Hz) will be recorded in mono.
> ...it's fine until you listen carefully - if you can hear MP3 "hiss"
> then you will likely be able to detect the mono reduction on "joint
> stereo"
>
> At 11:35 20/10/03 -0400, you wrote:
>
>
>> I have a couple of questions about record settings;
>>
>>
>> 1. Quality 1-7 relates to what bitrates??
>>
>>
>> 2. Joint stereo vs stereo difference.
>>
>>
>> Thanks ahead,
>>
>>
>> Bubba



Page was last modified "Jan 10 2012" The Rockbox Crew
aaa