[xcodeguy]

If I were to burn an Audio CD of iTunes Protected AAC songs and then imported the audio CD back into iTunes as AIFF - would there be any more loss of the already lossy compression of the original protected AAC music?

I know that if I went from AAC to Audio CD then import as MP3 I would get even more loss than the source. But does this hold true if you re-import as AIFF. Isn't AIFF lossless? And if so wouldn't that mean that the original 128 Protected AAC didn't sustain any loss during re-import as AIFF?

Hope someone can help me out...


Thanks everyone

 

[xcodeguy]

To the forum moderator:

After fully reading the 'sticky' to this forum - it looks like my above question is questionable. My appologies. Please delete this thread if you see fit. Sorry.

 

[Wodgy]

I don't think your question violates any forum rules.

Yes, you're right that doing this doesn't cause any additional quality loss. The only drawback is increased file size.

 

[Chri5peed]

You haven't factored in the 128Kb/s part. Discussing such low quality pap is almost against the rules of this forum.

 

[xcodeguy]

Quote:

Originally Posted by Chri5peed You haven't factored in the 128Kb/s part. Discussing such low quality pap is almost against the rules of this forum.

LOL! I agree. I'm in one of these situations..."If I only knew then what I know now..."

While I can re-rip my CD collection to a format that is much better quality (I think I would just go AIFF), I'm locked into the Ipod because of my iTunes Store downloads. It sucks but that's the way it is so...

 

[deagol]

You're only locked into iTunes as long as your AAC files have DRM on them. As soon as you remove the DRM (using a program or, in the way you have suggested, burning a ripping) they could play on any player that supports AAC. If you converted them to another file type, you could play them on any player. Of corse, all of these things will result in some quality loss, but at 128 kbps, that isn't a huge concern.

 

[pds6]

xcodeguy says:
Quote:

If I were to burn an Audio CD of iTunes Protected AAC songs and then imported the audio CD back into iTunes as AIFF - would there be any more loss of the already lossy compression of the original protected AAC music?

I believe the answer is Yes. The act of burning the AAC to cd and a new format causes a loss of digital quality.

TibBits states:
Quote:

But the question remains: how easy will it be for someone to convert one of Apple's protected AAC files into an MP3 file with no DRM or even identifying information? Not hard at all, in fact, because you can burn an audio CD from iTunes 4 of your purchased music, and then you can rip those files back to MP3, even retaining track names and other metadata. The process comes with some loss of quality that audiophiles will undoubtedly dislike but that won't bother most people (I can't hear it at all).

SEE: http://db.tidbits.com/article/07175

 

[blessingx]

Quote:

Originally Posted by pds6 I believe the answer is Yes. The act of burning the AAC to cd and a new format causes a loss of digital quality.

No there would be no loss in quality in the case presented.

And as mentioned as burning CDs is expressly permitted in your purchase agreement there is no problem addressing it here (though over-cautious deletion has occurred before).

 

[pds6]

blessingx says:
Quote:

No there would be no loss in quality in the case presented.

No big deal, but can you cite your source. I have read a number of sources that indicate that once the drm wrapper is removed (by whatever source) some of the music is removed in the process.

 

[blessingx]

Quote:

Originally Posted by pds6 No big deal, but can you cite your source. I have read a number of sources that indicate that once the drm wrapper is removed (by whatever source) some of the music is removed in the process.

I've never heard this. I'd be curious to read it, but it would seem to have been much more widely reported if it indeed was the case. Many sources refer to the reimportation of the files back in a lossy form will cause a quality loss. Effectively lossy to lossy transcoding. Even then if the secondary encoding has enough "headroom" the decrease may not be audibly perceptual. Try a test of 128 AAC versus 128 AAC to AIFF/WAV/PCM to 320 LAME MP3 and see if you can hear a difference. I transcoded some iTunes Store tracks when it was first launched to "--alt-preset standard" and couldn't. Limited test though.

Since AIFF is being discussed I suspect a few of you are on Macs. Remember the iTunes-LAME app is available.

 

[pds6]

I've seen it a number of times. Where?, I forget but will keep in back of mind.

I will add that the tibBits quote seems to support my position: Quote:

[C]onvert one of Apple's protected AAC files into an MP3 file with no DRM . . . comes with some loss of quality . . .

 

[blessingx]

That's the back to MP3 part I referred to as lossy to lossy transcoding. Even AAC to AIFF to AAC will do the same. So will non-DRM AAC to AIFF to MP3/AAC. The DRM has nothing to do with it. The mentioned AAC to AIFF shouldn't though and again the loss may not be audible in the other cases if you're careful.

 

[pds6]

blessingx says:
Quote:

AAC to AIFF shouldn't, (but loss when) ... AAC to AIFF to AAC and/or AAC to AIFF to MP3/AAC

I will look it up and report back. I agree, the drm wrapper may be a red herring, but I believe the act of re-encoding from AAC to MP3 does create a loss of quality.

I would add that if a re-encoding (AAC to AIFF) creates a "perfect" encoding of the AIFF file. A re-re-encoding (AAC to AIFF to MP3) should have no effect. I don't believe a re-encoded AIFF is of the same quality as a freshly ripped AIFF file.

 

[xcodeguy]

Quote:

Originally Posted by pds6 I would add that if a re-encoding (AAC to AIFF) creates a "perfect" encoding of the AIFF file. A re-re-encoding (AAC to AIFF to MP3) should have no effect. I don't believe a re-encoded AIFF is of the same quality as a freshly ripped AIFF file.

I think this is true - sound logical anyway. My goal is to not lose anything more from the original 128, hence AAC to Audio CD to AIFF. I think re-encoding (*brining it back in*) from anything but AIFF will result is some loss - and these files are already at 128 so...

 

[blessingx]

There are several ways to think about this.

A. They're so low a bitrate so you wouldn't want to decrease the SQ any more.
B. They're so low a bitrate transcoding at high lossy bitrates shouldn't substantially affect the SQ.
C. They're so low a bitrate they aren't worth uncompressed/lossless file sizes.
D. All of the above.

Seriously pick a couple tracks. Have 128 AAC, AIFF and reencoded 320 kbps & --alt-preset standard/extreme MP3s and compare them. Transcoding is frowned upon around these parts for a good reason, it's rarely ideal. However very few people test transcoding. Transcoding will always share less information with the original source. It is in essence less bit perfect (though never bit perfect as it's perceptual compression) if transfered back to a uncompressed state. When it is necessary to transcode though it doesn't mean if you take proper steps that new imperfections/secondary artifacts are always audible.

I'm going to step away from this thread, but do yourself a favor and test.