Batch convert from mp3 to FLAC Lossless

[Floyd]

I ripped my CD's to FLAC uncompressed and ALAC and LAME 320kbps simultaneously.
Just experimenting with batch converter... I can convert the LAME version back to FLAC uncompressed and it appears to do this ok and appears to be 0% compressed.
Is the conversion from LAME back to FLAC uncompressed really really 0% compressed and essentially as good as a FLAC uncompreesed rip and theoretically the LAME rip could be converted to WAV?
Also I take it if this is the case,it would not work converting just any mp3 music file to FLAC uncompressed using the batch converter.
I assume it would only work if the original rip to LAME was done with dbP?
Thanks

[Dat Ei]

Re: Batch convert from mp3 to FLAC Lossless

Hey Floyd,

you're mixing up different kinds of compression. Flac compression is lossless, just a compression based on the data, the digital values. It's like zip compression - you can convert back and forth without any loss.
mp3 compression is lossy. mp3 tries to reduce audio data by assuming that you can hear or miss some of the signals of a complex audio signal. Once those signals are lost, they are lost forever - you can't reconstruct them.
Best practise: rip to flac, keep those files as your originals, and convert those to lossy mp3 copies whenever you need small transportable files.


Dat Ei

[Floyd]

Re: Batch convert from mp3 to FLAC Lossless

Thanks Dat..
Just that when I convert from a LAME CBR at320kbps dbP ripped album to FLAC Lossless each track seems to be the same size as the FLAC Lossless that I originally had.
Remember, originally I ripped to FLAC, ALAC and LAME simultaneously...then did a conversion of the LAME back to FLAC uncompressed just as an "experiment".
I do keep my "master" copy a FLAC uncompressed.
So I was just wondering in this instance of going from LAME to FLAC... does it just pad out the data or ?
Seems odd that the LAME conversion to FLAC is exactly the same size for all tracks on an album as my master FLAC copy for the same album.
Was just wondering.

[garym]

Re: Batch convert from mp3 to FLAC Lossless

I ripped my CD's to FLAC uncompressed and ALAC and LAME 320kbps simultaneously.
Just experimenting with batch converter... I can convert the LAME version back to FLAC uncompressed and it appears to do this ok and appears to be 0% compressed.
Is the conversion from LAME back to FLAC uncompressed really really 0% compressed and essentially as good as a FLAC uncompreesed rip and theoretically the LAME rip could be converted to WAV?
Also I take it if this is the case,it would not work converting just any mp3 music file to FLAC uncompressed using the batch converter.
I assume it would only work if the original rip to LAME was done with dbP?
Thanks

As Dat Ei has pointed out, your idea about how this works is incorrect. Once you create an mp3 file with LAME (even if created *from* a lossless FLAC file), the resulting mp3 file CANNOT be converted back to a lossless FLAC file. As you've seen, you can convert the mp3 file to FLAC format, and it will be a larger file. But this is because of a bunch of padding. The conversion to mp3 "threw out" data and that cannot be recreated. One can take a very low quality, low bitrate mp3 file and convert it to FLAC. But all you have at that point is very low quality mp3 file contained within a FLAC container with a lot of wasted space.

[Floyd]

Re: Batch convert from mp3 to FLAC Lossless

Thanks.
Thought it was the case but maybe dbP was able to do some "magic" somehow
So in looking at the properties of a track in the id-tag I guess the real way to tell the source of the file is to look at the source field.
In the attachment below for the same track on the same album the FLAC done from CD is on the right and the FLAC done from LAME is on the left.
The Source field seems to tell the story.

FLAC from LAME - Source CD (Lossless) >> Very High (Lossy) [mp3]
FLAC from CD - CD (Lossless)

Is this the same story for going from say FLAC Lossless (level 5) and trying to convert to FLAC uncompressed using dbP converter?


(Maybe, as an aside, a way of checking if you purchase what you think is a "FLAC" copy online to make sure that you are getting what you paid for perhaps...)

[garym]

Re: Batch convert from mp3 to FLAC Lossless

Except FLAC files created not using dbpa may not have that SOURCE field.

[Floyd]

Re: Batch convert from mp3 to FLAC Lossless

Sorry to bother with another question..
When you rip to FLAC, say level 5 for instance (or other levels of FLAC), can you convert this to FLAC uncompressed without "losing" any data / quality?
Thanks

[Dat Ei]

Re: Batch convert from mp3 to FLAC Lossless

Hey Floyd,

yes, you can. Because flac compression is lossless (like zip and other data compression algotrithms), you can convert back and forth between different compression levels without any loss. But keep in mind: uncompressed flac has the same audio quality as any other compressed flac. The differences are just the resulting file sizes and the need for cpu time for compression and decompression.


Dat Ei

[garym]

Re: Batch convert from mp3 to FLAC Lossless

Hey Floyd,

yes, you can. Because flac compression is lossless (like zip and other data compression algotrithms), you can convert back and forth between different compression levels without any loss. But keep in mind: uncompressed flac has the same audio quality as any other compressed flac. The differences are just the resulting file sizes and the need for cpu time for compression and decompression.


Dat Ei

correct, and also keep in mind that the extra CPU time is almost all for the compression/creation of the FLAC file. Decoding effort is essentially the same whether the FLAC is uncompressed or compressed at level 8. Personally, I use FLAC level 5.