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Subject: Re: High kbps/Low kbps power consumption
From: stevem_at_gator.net
Date: 2003-06-06


Now for my even dumber question: What is so bad about "transcoding" from a
higher-encoded mp3 to a lower kbps, as opposed to ripping right from an
original audio file?

(I can imagine a few things, but you sound like you could explain
definitively...)

thanks,

Steve

> At 02:37 PM 6/5/2003, Neon John wrote:
>>No, not a bug. Just an effect of running the thing at the edge of its
>> performance envelope. Contemplate how much data the thing has to move
>> to handle that bitrate and how much processing it takes and how much
>> power that requires. Given that there is a fixed amount of RAM, the
>> higher the bitrate the more often the drive runs. More power required.
>> You're simply overwhelming the unit and with no material gain in sound
>> quality.
>
> no offense, but that's a load of rich creamery butter. my JBR is
> happily playing 320K mp3's right now with only 30% battery life left.
> not a skip to be heard in 80 minutes (so far) of playing.
>
>>I have very good ears and I can't hear the difference between the
>> original CD and 192kbps even on my mid-level home system playing
>> directly from the computer. I certainly can't hear the difference once
>> the sound goes through the Archos' audio output circuit and then
>> through headphones, even my PortaPros. It is a waste of space and
>> processing power to put anything above 128kbps on the Archos, unless
>> perhaps you're using the digital out to a high end system.
>
> now this is a totally different issue. i agree in principle that 192K
> is generally OK for most things and that 320K is generally overkill.
> however i have found a few pieces where i can definitely hear artifacts
> at 192K. not many.
>
> in fact this is why i recommend using LAME's "--preset standard" mode.
> it averages 192K anyway, and the sound quality is superb. it can
> "burst" up to 320K if needed. the only drawback is it is significantly
> slower to encode a file than using 192K CBR.
>
>>I store all my rips at 192kbps on my computer. I downsample to 128kbps
>> for the Archos using CDex and LAME. On this 2 gig machine the process
>> is quite rapid. Since I have the disc space I simply maintain two file
>> trees, one for the original rips and one for the archos.
>
> i hope you are not transcoding the 192K files to 128K files but rather
> generating the 128's from the original wav or cd.
>
>>Best thing to do is simply experiment some. Downsample to various
>> rates and do some listening tests. When you find something you like,
>> check the battery life. You'll be pleasantly surprised.
>
> agreed.
>
> -jsd-



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