Hello!

So, I have a really strange issue. I downloaded from the internet an album in flac and then I converted it to mp3@320 with the latest version of dbpoweramp. What happened is that the mp3s that resulted after the conversion we're larger than the original flac. For exemple track 1.flac was 20MB and the resulted track 1.mp3 was 28MB. I even converted all the flacs to wav and then back to mp3 but I still got all the mp3s larger than the flacs. I have done this before many times. This is the first time when it happens.

Did anybody around here experience this issue?

Thanks a lot!

Hi.

If you mean that you're encoding to MP3 in CBR at 320Kbps then the tracks will be around 2.3MB per minute. How long are these tracks in terms of playback duration?

Cheers, Slipstreem.

It's an album with Rachmaninoff so the tracks are quite long. Track 1 has 12 minutes and 9 seconds.

I agree with slipstreem, we need to know the length of the tracks. Also, what bitrate are the FLAC files using? Are the songs comprised of silence? If the FLAC files use a bitrate less than 320kbps (it looks like it) then they may not in fact be lossless. Then again, the songs could be complete silence (or close to that).

12 minutes 9 seconds at 2.3MB per minute = 28MB. It's exactly the size you'd expect it to be at 320Kbps in CBR.

Have you considered using LAME in VBR mode at -V3 instead? The files will end up much smaller but I very much doubt if you'll hear any difference. If you do hear a difference then try -V2.

Cheers, Slipstreem.

It is possible, but not probable, that the FLACs compress the music down to less than 320kb/s.

I've personally seen some extreme scenarios of Lossless being extremely efficient. I know in testing, I saw WMA Lossless with 16-bit/44Khz CD content go down below 320 kbps in at least 100 cases. I'd expect FLAC to have similar rare big win scenarios, too.

I've seen this once with an Opera album. But it was mono. 16-bits mono speech may also compress below 320 kBit/s.

Would it be accurate to say that music that's highly compressible in FLAC is also likely to be highly compressible in LAME VBR? My limited knowledge says "yes", but I'm keen to learn.

Cheers, Slipstreem.

Music that can be highly compressed using FLAC has the potential to be highly compressed with Lame VBR. I say it has the potential because that is not always the case. I have my library backed up to Apple lossless so I can kind of draw a comparison. The average bitrate in my library is about 1100kbps. I have a song that comes out to ~160kbps VBR when using Lame mp3 3.97 at -V 2 --vbr-new. That same song encoded in Apple lossless (from the source CD) takes up about 1000kbps. Lossless formats use different compression techniques over lossy formats. However, if a lossless file comes out to below 320kbps, I think it is safe to say that a Lame VBR mp3 file at -V 2 or lower would come out at a very low bitrate.

OK... So, it says in the propreties that the flac file has an bitrate of 1411kbps. I've tried to convert it to mp3@VBR V0 "extreme" and I got from 20MB (flac file) to 12.4MB for the mp3. So flac encodes are VBR? I have also uploaded track 1.flac so you may check it up to see what you discover.

Thanks!

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a) FLAC encodes (as well as other lossless encodes) are VBR.

b) It happened rarely (and only with classical music), but I too have run upon tracks which losslessly encoded yielded a bitrate around 300 kbps.

That FLAC's bitrate is 227 kbps and it seems pretty silent and mono, so it's normal to have so low bitrate and you should use VBR with MP3.

Not only that flac files are VBR, flac also uses something similar to joint stereo. So it can compress classical music with a lot of silent parts and with very little difference between channels very efficient. That's why you got smaller files with flac as with LAME. Try using VBR LAME, don't force it to use 320kbps if it's not needed...

All in all, CBR shoul nowadays ONLY be used for compatibility reasons for use on some really old hardware players. In all other scenarios VBR should be used!

How can I find out the actual bitrate of a FLAC? Thank you all for helping me out!

Mr QuestionMan
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