Skip Encode of MP3 Files Under [x] Bitrate

[qwecom]

I haven't seen this option, and it may not be practical for cross-format conversions. My apologies if it exists. I am only thinking in terms of "resampling" existing MP3's at lower bitrates.

Feature:

• Skip Encoding Files Under [[COLOR=DarkRed]x[/COLOR]] Bitrate

Possible Variations:

• Copy Existing File if Under [[COLOR=DarkRed]x[/COLOR]] Bitrate
• Copy Existing file if Average Bitrate is under [[COLOR=DarkRed]x[/COLOR]]
• Skip Files Under [[COLOR=DarkRed]x[/COLOR]] Bitrate
• Skip Files with Average Bitrate Under [[COLOR=DarkRed]x[/COLOR]]
• Rip & Compare (Keep file with lower bitrate)
• Rip & Compare (Keep file with smallest file size)

Situation:

You want to download all your favorite MP3's to your portable player at a particualr bitrate, but your PC Library consists of a diverse collection of MP3's with differing constant, Average, and Variable bitrates.

For the sake of argument, you want to reduce the bitrates to an arbitrary setting (say 128kbp). Some files in your collection may actually be 64kbp, 96kbp or already at 128kbp.

Upsampling low bitrate files to higher rates would be inefficient, increase file sizes, and destroy what little quality remains, so it would be a great way to preserve and/or skip them.

Potential Problems:
• Is it actually possible to determine the ABR or VBR settings used to record an MP3? Is that embedded in the file itself? (I don’t know)

• If it is not possible to read the ABR/VBR rate, perhaps the current file could be parsed to calculate the effective “ABR” of the file.

• If the current ABR & VBR rate can’t be determined, keeping the file with the smallest filesize might be a “cheap” alternative

• I don’t know that conversions to non MP3 formats would be compatible with any comparison other than file size.

Comments:

I’ve tried to think about this as a programmer, but this might be such a “nitch” feature focused on “MP3” files that it’s not worth the bother. I figured I’d write up the request anyway.

I’m not sure whether it’s possible to determine the ABR/VBR settings used to encode an MP3. I’ve looked at several programs that display bitrates (including Windows XP when you enable the “bitrate” column of a detailed directory view), and they often seem to randomly grab the initial VBR of the first few seconds of the MP3.

[LtData]

Re: Skip Encode of MP3 Files Under [x] Bitrate

I know with sveta you can set it to re-encode files that have a bitrate above a certain number and then send them. It works for any format that Sveta supports and you ahve the codec for. It ignores any bitrates under this limit.

[qwecom]

Re: Skip Encode of MP3 Files Under [x] Bitrate

Thanks.

And, I realize that resampling is a "lossy" proposition, and ideally I should go back to my CD's and reRip.

But, sometimes going back to the source is inconvenient and impractical. If I'm listening in a car or on a plane, there's enough ambient noise that I don't mind a reasonable quality loss from resampling.

After reading about the additional problems of throwing "Joint-Stereo vs Duel Stereo", "VBR to Constant", "Cross-codec encoding (IE blade to Lame)", and the general subjectivity of "quality"... a comparison of bitrate may not be enough of a test. Perhaps the only comparison that may make sense is the "Ripped File Size".

I read a cross post with links about these issues:

http://www.hydrogenaudio.org/forums...topic=30637&hl=

http://www.audiograbber.com-us.net/boards/ubb/Forum1/HTML/001538.html

The feature would be pretty much restricted to folks who are "going to do it", find the loss of quality acceptable, and just want to automate the process.

Any other comments or ideas?

[LtData]

Re: Skip Encode of MP3 Files Under [x] Bitrate

True, bitrate isn't the end-all to knowing the quality of a song. However, it is a good start at determine how high/low the quality of a song could be.