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Topic: Would MP3 Give Better Quality at V4.8 than at V5? (Read 4685 times) previous topic - next topic
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Would MP3 Give Better Quality at V4.8 than at V5?

Hello everyone, I am new to these forums, in fact I just signed up 10 minutes ago. I do have a question regarding the VBR functionality of MP3, especially with emphasis on quality. So here goes:

Suppose that I encode an MP3 file at V5, and the overall bitrate of that file works out to approx. 109 kbps, which is surprisingly low for a level of quality which is meant to rival and improve upon the old 128 CBR.

Now, suppose that I take my original source and I re-encode it again, several times actually, trying out different "V" settings between V4 and V5, until I finally arrive at a file with an overall VBR bitrate that happens to work out to exactly 128 kbps. Let's say that the "V" setting that finally got me to that bitrate was V4.8,

Because my V4.8 file yields an overally bitrate of 128 kbps (VBR, not CBR), is it going to give me any higher quality at all than my V5 file at 109 kbps? Is there any possibility that LAME adds some padding to (what would normally be) a V4-quality file to give it this extra filesize, but no actual improvement made to quality (in similar fashion to how MP3 Packer would do)? Is there a way that the V5 file could still come out sounding of higher quality, due to the precision tuning of the psycho-acoustic model? Or, would the quality of the V4.8-encoded MP3 file actually benefit from the slight increase in bitrate?

Thanks,
ETM.

Re: Would MP3 Give Better Quality at V4.8 than at V5?

Reply #1 –
Quote
Because my V4.8 file yields an overally bitrate of 128 kbps (VBR, not CBR), is it going to give me any higher quality at all than my V5 file at 109 kbps? Is there any possibility that LAME adds some padding to (what would normally be) a V4-quality file to give it this extra filesize, but no actual improvement made to quality (in similar fashion to how MP3 Packer would do

If it wasn't transparent at 109 kbps, there is a chance that increasing the bitrate to 128k could improve that.

Quote
Is there a way that the V5 file could still come out sounding of higher quality, due to the precision tuning of the psycho-acoustic model?

Anything is possible.  Not very likely though.

Re: Would MP3 Give Better Quality at V4.8 than at V5?

Reply #2 –
Quote from: ExtraTerrestrialMud on
Suppose that I encode an MP3 file at V5, and the overall bitrate of that file works out to approx. 109 kbps, which is surprisingly low for a level of quality which is meant to rival and improve upon the old 128 CBR.
It is not at all surprising. "V" for "variable" in VBR, means the encoder tries to spend more bits where it is needed, and less bits where it is not. So if implemented well, you will on average hit a "CBR 128 equivalent" with less bits (for example, you don't need 128 for total silence parts).

And there is no reason why a single random file will hit the average.

If -V5 produces annoying artifacts (... TOS#8, blah blah blah), then going to -V4.8 is a small change. As saratoga says, there is a chance that the additional 19k could fix it, but there is a chance that it needs more. As long as you keep your lossless originals, you can just throw away your -V5 and use -V4. Spending time finding the precise 4.something is OK if out of curiosity, but how much time do you want to spend listening for errors rather than listening to music?




Re: Would MP3 Give Better Quality at V4.8 than at V5?

Reply #3 –
There is no reason to not beleive in the V5 setting just because a particualar track needs less bits. That's just VBR.

V5 is fine for nearly any track. There are few tracks where it isn't, but if you want to take care of them you should use a higher quality setting. But as Porcus said if you really want to take care of those samples you usually have to take a much higher setting like V3 or better. V4.8 isn't worth while. With today's mass storage capacities and prices V3 or better is quite worth to consider though we're talking about reaaly reare samples.
lame3995o -Q1.7 --lowpass 17