Converting from lossy AAC to lossless FLAC

[mattjax05]

I use a Squeezebox Receiver and buy songs off iTunes. However when playing these files it can be slow and the Receiver seems to get out of sync with the Squeezebox Server (something to do with converting AAC to FLAC before playback on the fly I believe)

Therefore I propose to convert to FLAC before hand. Just converted a song using dBpoweramp and the file size has increased significantly! Does anyone know where all this extra data has come from? I don't want to degrade the original file by introducing unwanted data.

I understand that a compressed lossless file can be increased in size back to it's original file but I thought a lossy compressed file can't and the data lost in transit is irrecoverable!

Hope someone can help.

Thanks. Matt

 

[idc]

Think of it as the same amount of words, but now in a bigger book than before.

 

[Anonymous]

You can't convert directly between an AAC and a FLAC format. If you think about it they both contain different types of data however the end result is just a representation the sound as a number of different pressure measurements. The AAC has probably been converted to a 16bit / 44k PCM format before then being converted into FLAC. As for how well that was done it will depend on the quality of the decoding software I would guess but I wouldn't worry about it too much. I am surprised that you needed to do this at all though.

EDIT: Or what idc said in his more compressed format!!

 

[Alec]

Songs will always appear bigger when you transcode them to a bigger format, but this does not mean the lost data has been replaced; its just empty data i thik, or a kind of guesstimate at what was there before. Whether it degrades sound quality or not im not so sure to be honest, tho i suspect it shouldnt...

 

[Anonymous]

It's not empty data, it's the raw PCM data (from the decoded AAC files) re-encoded in the new format. As you say the new format takes up more space on disk.

 

[Alec]

Stereolad:

You can't convert directly between an AAC and a FLAC format. If you think about it they both contain different types of data...

How so? Here, they both seem to contain music. I'm confused.

 

[mattjax05]

idc:Think of it as the same amount of words, but now in a bigger book than before.

Simple yet effective, thanks idc. So I have a book full of blank pages........

 

[mattjax05]

Stereolad:

I am surprised that you needed to do this at all though.

I don't want to but I find it frustrating playing aac files with cut outs!

 

[nads]

how is the receiver connected to the server?

 

[mattjax05]

al7478:Stereolad:

You can't convert directly between an AAC and a FLAC format. If you think about it they both contain different types of data...

How so? Here, they both seem to contain music. I'm confused.

I think Stereolad means you need to convert back to the original pcm before then converting to a new format?

 

[nads]

mattjax05:al7478:Stereolad:

You can't convert directly between an AAC and a FLAC format. If you think about it they both contain different types of data...

How so? Here, they both seem to contain music. I'm confused.

I think Stereolad means you need to convert back to the original pcm before then converting to a new format?

if the file is a lossy file they you have lost the data and converting it to PCM or flac will gain you nothing other than less storage space as you will have a lager file with the same data.

sounds more like a set up problem.

 

[mattjax05]

nads:how is the receiver connected to the server?

The wonderful world of wireless! TBH I'd love to run an ethernet cable between the two, it's not been too reliable recently (won't connect/stops playing music) and I can't think why.

I hear there is a new version of the server available? I have the server installed on a Netgear ReadyNas Duo.

 

[mattjax05]

nads:mattjax05:al7478:Stereolad:

You can't convert directly between an AAC and a FLAC format. If you think about it they both contain different types of data...

How so? Here, they both seem to contain music. I'm confused.

I think Stereolad means you need to convert back to the original pcm before then converting to a new format?

if the file is a lossy file they you have lost the data and converting it to PCM or flac will gain you nothing other than less storage space as you will have a lager file with the same data.

sounds more like a set up problem.

I agree

 

[idc]

mattjax05:

idc:Think of it as the same amount of words, but now in a bigger book than before.

Simple yet effective, thanks idc. So I have a book full of blank pages........

You don't have any blank pages, it is just that each page now has fewer words and bigger spaces between them.

 

[Gerrardasnails]

mattjax05:nads:mattjax05:al7478:Stereolad:

You can't convert directly between an AAC and a FLAC format. If you think about it they both contain different types of data...

How so? Here, they both seem to contain music. I'm confused.

I think Stereolad means you need to convert back to the original pcm before then converting to a new format?

if the file is a lossy file they you have lost the data and converting it to PCM or flac will gain you nothing other than less storage space as you will have a lager file with the same data.

sounds more like a set up problem.

I agree

Me too.

Lossy can't be made lossless full stop.

 

[nads]

mattjax05:
nads:how is the receiver connected to the server?

The wonderful world of wireless! TBH I'd love to run an ethernet cable between the two, it's not been too reliable recently (won't connect/stops playing music) and I can't think why.

I hear there is a new version of the server available? I have the server installed on a Netgear ReadyNas Duo.

i would try running wired as most problems tend to be from wireless interference, and yes there have been quite a few updates current one is 7.4.2 from feb 22nd

 

[Anonymous]

mattjax05:al7478:Stereolad:
You can't convert directly between an AAC and a FLAC format. If you think about it they both contain different types of data...

How so? Here, they both seem to contain music. I'm confused.

I think Stereolad means you need to convert back to the original pcm before then converting to a new format?

Sort of, but I wasn't suggesting course of action. It is impossible to convert from the AAC format to FLAC without the data being converted into the intermediate format of PCM data (the AAC and FLAC formats are just ways of encoding this data after all). This is why you can convert between two compression formats provided you can decode from the one (i.e. generate PCM data from the compressed file) and encode to the other (generate the compressed representation of the audio from PCM data). Yes the audio that the FLAC then represents is only as good as could be retrieved from the AAC file, however the size it will occupy on disk will be related to the the FLAC compression applied to 16bit / 44K representation of the data.

As I said I don't know why the OP has needed to do this to get around the original problem; it seems unfortunate.

Right now I need a lie down.

 

[Binman]

I have had the exact same issue with my Squeezebox Classic. Most of my music is FLAC, but I convert my aac stuff into Lossless, just like you do using dppoweramp.

For those who don't understand why I have to do this:

My music is stored on a very small, but very low powered PC, streamed wirelessley to the SB. As aac isn't natively supported by the SB, it has to be transcoded at the PC before transmission, and as the PC is slow (500MHZ processor, 512K Ram), it cant transcode in time. FLAC makes bigger files, but no transcoding required, so it works.

When streaming FLAC, the percentage of the wireless bandwidth being used is tiny, so I know its not a setup problem in my case.

 

[Anonymous]

hey,

i am actually looking for the opposite flac->apple lossless.

what can i use?

(hope you don't mind i post it here)

thanks,

Dan.

 

[daveh75]

lt_dan:i am actually looking for the opposite flac->apple lossless.
what can i use?, http://www.dbpoweramp.com/

 

[Anonymous]

I am not an expert on Squeezeboxes, but as a thought rather than decoding the AAC and then encoding to FLAC in realtime in order to stream, can you not just stream a PCM wave ?

Granted the this will use slightly more bandwith (1536kbs) than FLAC but it should not max out 54G wi-fi network.

I can easily stream 4000-5000kbs MPEG2 video wirelessly to my laptop at home without issue, so if it is possible to send pure wav with a Squeezebox, then you should get better performance as I think the FLAC encoding is where the problems lie.

 

[mattjax05]

bendrummond:
I am not an expert on Squeezeboxes, but as a thought rather than decoding the AAC and then encoding to FLAC in realtime in order to stream, can you not just stream a PCM wave ?

Granted the this will use slightly more bandwith (1536kbs) than FLAC but it should not max out 54G wi-fi network.

I can easily stream 4000-5000kbs MPEG2 video wirelessly to my laptop at home without issue, so if it is possible to send pure wav with a Squeezebox, then you should get better performance as I think the FLAC encoding is where the problems lie.

Right, been trying all night transcoding AAC to WAVE and all the time when playing on my squeezebox I get a 1 second 'FUZZ' from each WAVE file at the end of every track. I'm using dBpoweramp. If I transcode to FLAC it's fine.

 

[Anonymous]

Right I am not sure technically whether the music is actually being streamed or the Squeezebox just plays/decodes file stored elsewhere on a network hence why it won't play DRM AAC files

Can you elaborate on the relationship between dbpoweramp and the Squeezebox ? Do you have to configure dbdpoweramp in someway such as using the AssetT UPnP (DLNA compatible) server ?

 

[mattjax05]

bendrummond:

Right I am not sure technically whether the music is actually being streamed or the Squeezebox just plays/decodes file stored elsewhere on a network hence why it won't play DRM AAC files

Can you elaborate on the relationship between dbpoweramp and the Squeezebox ? Do you have to configure dbdpoweramp in someway such as using the AssetT UPnP (DLNA compatible) server ?

Hi

There is no relationship between dBpoweramp and Squeezebox. I just use dBpoweramp to transcode and then drag and drop the files to my NAS. When my Squeezebox plays the file it creates a fuzz/scratch sound at the end of the track. Only tried transcoding AAC to WAV. Now going to try FLAC to WAV.........

 

[Binman]

The latest version of Squeezebox Server (v 7.4.2) says it fixes 'Audio glitches at the end of WAV/AIFF files'. May be a fix for your problem