Compressed FLAC Wont Decompress

Have you tried converting it to WAV first?

No not tried that, will try it but surely it should decompress fully

Indeed it should. But converting it to WAV is quick and will probably get it done.

I don't get it.  If the FLAC is compressed and you believe that compression "loses information"  Isn't uncompressing it going to give you a larger file that still has lost information?

My understanding is that FLAC does not lose information but just stores it more efficiently so allowing for smaller file sizes.

Yes.  But if it is already "lossless" then expanding it to WAV will not restore data that was never lost.  But if you believe, as some do, that lossless files really do in fact lose data, then taking a file with lost data and expanding it to WAV (uncompressed) will not do anything.  Am I wrong?

A file is either "lossless" or it isn't. If it has lost data then, by definition, it isn't lossless.

Look at it like this - this thread, as it's displayed on your screen, has a load of blank lines doesn't it?  If I remove every blank line and replace each bunch of blank lines with just a count of the number of blank characters (spaces) I've removed then chances are this number will occupy less space than all the blanks I removed.  I've compressed the file, but not lost any actual data.  I can recreate the file exactly by inserting the exact number of blanks that I counted as I removed them.  This is the principle of FLAC.

IF, on the other hand, I leave each and every blank in place, I still have all the data but without any compression... like WAV.  

Simples....

Sj

Good analogy, but if the flac cant decompress fully to zero percent then does it mean that something is corrupt and its doesnt know how many blank lines have been removed in certain parts of the file

Graeme

Graeme, indeed this is strange.. As I understand Uncompressed FLAC may well use an internal coding variant  to simply store the discrete PCM sample integer values within its container (aleg found the reference describing this capability on another thread). Therefore I can't see why it still states the file is still compressed. Perhaps one for the dbpoweramp support web site... I'd be inclined to convert to WAV then re encode as compression free FLAC.

Simon

Will try this later when i get home. Thing is can WAV be compressed? if not I'm wondering if this will then just take the 33% compressed FLAC and convert it bit for bit to WAV (sorry for the terminology) But when i convert back to FLAC it will be 0% compressed as the data will have been lost already. If that makes sense.

Foxman - if there is an error and data corruption I suspect it won't convert to WAV anyway. Also I would imagine if the corruption does however somehow remain it won't sound subtle.. and will be obvious something is awry.

Simon

Simon, to be honest its only a free download from HDTracks so I'm not bothered about the actual album. I'm just really curious now following the conversation the other day about FLAC compression.

As soon as i've managed to do the conversion ill post back

Graeme

OK the Original file, which is track 4 on the HDTracks free download album, was if memory serves 65% compressed and around 48Mb in size. After conversion to Uncompressed FLAC
with DbPowerAmp the file came out at 33% compressed and 89Mb in size.

Converting this file to WAV it comes out 0% compressed and 140Mb in size. Converting back to FLAC, using the No Compression setting, it converts back to its original 33% compressed 89Mb size.

Any ideas??

Only ideas, no proof. The file sizes sound about right so it might be that the FLAC has a read/process error. Does the WAV sound OK and have you tried pulling the FLAC down again? Not sure if the HDT downloader will let you do this. What a load of mucking about for a freebie! Not so free after all - unless your time is worth nothing.

Hi Harry

That was the first thing i tried, downloading again. Same issue. As i said its only a freebie, just a good way to hear new music. Ive not tried playing the two tracks back to back.

The reason I'm curious is that I've noticed this before but never thought too much of it. Following a discussion the other day, Simon was, as usual, very informative and it got me thinking when this issue came up again.

All the other tracks converted fine

Graeme

It is my understanding that 'Uncompressed FLAC' can still be compressed if either:

the source is 24 bit

there is true digital silence (lots of zeros).

Many thanks MrSpoon, interesting to know