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View Full Version : Any fidelity lost going from Variable to Lossless?



JoeRip
11-14-2006, 09:00 PM
I have a pretty specific question. There's a long story behind it, that we can cover at another time. However, for now, I'd prefer to just stick to this specific question.

I have some 4000 songs that were ripped with these settings:

Windows Media Audio 9.1 (WMA)
VBR Quality 98, 44kHz, 16 bit stereo 1-pass VBR

Most of these files are between 400 and 500 kBps, but some of them fall as far down as 210 kBps.

Due to circumstances beyond my control, I'm going to use DMC to convert these files to match all of my other files, with these settings:

Windows Media Audio 9.1 Lossless
VBR 100, 44 kHz, 2 channel 16 bit 1-pass VBR

Basically, I'm converting from a very high variable bit rate to a lossless format, which will grow the file size by about 100%.

My question is; do I lose any fidelity in this conversion? Or are all of the "original bits" (as located in the Variable Bit Rate version) actually in the Lossless version, just padded out?

ChristinaS
11-14-2006, 09:38 PM
Lossless means just that: identical in quality to the original from whihc you start. If yuor lossless file was from a wav, then it's as good as that wav.

Regular wma (not lossless) is lossy, whether VBR or CBR or no matter what. So you have already lost quality when you converted you wav (or audio cd track) to this lossy wma - even the professional one you used.

Converting this lossy format to lossless wma now will gain nothing in quality, because you cannot gain quality. The lossless wma will be the same audio quality as the lossy wam, but in a much bigger file. Don't expect to have the quality that lossless would have had from the origjnal wav. It can only have the quality of the already losst wma you are planning to convert to lossless wma.

Going from wma to wma lossless only uses up more space - for no good reason.

JoeRip
11-14-2006, 10:18 PM
Note that I didn't ask if it (source file, a high quality VBR) would gain quality. I specifically asked if it would RETAIN exactly the quality it started with, even though there is a conversion going on here (if I understand it correctly, Spoon's code will convert the WMA HQVBR to WAV, then to WMA Lossless).

So is that a yes? There will be no loss in fidelity at all?

ChristinaS
11-14-2006, 11:29 PM
There should not be any loss with respect to the audio quality of your input file. Only a much larger resulting file.

Spoon
11-15-2006, 02:46 AM
There would be little point going from normal WMA >> WMA Lossless.

JoeRip
11-15-2006, 09:16 PM
Yeah, that would be the "There's a long story behind it, that we can cover at another time" part.

The point of this would be thus:

I have 6000 files ripped WMA Lossless. I have 4000 files ripped WMA High Quality VBR. I have 300 files WMA low res, 128 to 320. I have 3000 files in Mp3 of quality ranging from 128 to 320.

When using my media manager (name withheld) with my device (name withheld), my media manager and the device negotiate on how to transfer media. After they exchange capabilities, I have two choices:

1. let the device decide what files it can play, and which need conversion
2. force all formats to WMA 192 CBR.

When converting WMA Lossless, choice 1 yields WMA 300 CBR. I could live with this.

When converting WMA High Quality VBR, choice 1 yields NO CONVERSION. This means 500kbps files are simply copied, taking up enormous space. I can't live with this (run out of room too quickly).

If I choose the second option (force everything above 190 to WMA 192 CBR), then many of my low res WMA's (which have already been optimally converted) and my MP3s are forced to be converted. This is not a quality loss I'm willing to live with.

Given that the only real failure here is that all WMA Variables fail to convert under option 1, I'm considering simply converting all them "up" to WMA Lossless, since they will then correctly be converted to WMA 300 when copied to the device.

You see? A long story. Providing this story FIRST would simply have resulted in lots of "your media manager sucks, your device sucks, krypton sucks" arguments, instead of the data I needed.

Since it appear that the expected conversion path:

WMA High Quality VBR >> WMA Lossless >> WMA 300 CBR

isn't really any worse than the ideal (under the circumstances) path of:

WMA High Quality VBR >> WMA 300 CBR

then it seems reasonable to go ahead and "up" convert my HQVBRs, until such a time as I can go back and re-rip those CD's to WMA Lossless.