is apple lossless real lossless? - Page 2

 

Compress lossless gets decompressed on the fly, so what you actually hear is the decompressed signal.

 

If I compress a file using either a lossy or a lossless approach and play (or see) such file without decompressing it, I would likely get some random noise stuff coming out.

Not really, it's just that it's a totally different format when compressed. It's only a representation of what the audio data is rather than actual audio data, and a DAC couldn't read the compressed data on its own. If it could it would just be a garbled mess I believe.

This shouldn't be news to anyone, but basically any encoded audio file needs to be decoded (usually to LPCM - what WAVs normally contain) during playback.

 

The input might be 10, 100 or 1000 kbps but the output will always be 1411.2 kbps for 44.1 kHz, 16 bit, 2 channel audio.

Edited by xnor - 2/12/13 at 2:34pm

I'm not 100% sure on this, but upsampling would provide a better representation of the signal (higher sampling rate provides a better "picture" of the true signal). I don't think this necessarily means that it would have better sound quality, but the thought of having a higher sampling rate would make sense to provide a more accurate signal. Of course the upsampling probably isn't perfect so it might degrade the signal actually.

 

Audirvana Plus on Mac OS X provides an over sampling option. I don't use it though.

 

As for ALAC or FLAC, it's just like a .zip file. You put a file in it and it gets compressed. Later when you need that file, you unzip the .zip file and you get your original, uncompressed file back in pristine condition. Likewise, for ALAC, you put a lossless music file in a .zip-like container that happens to be called ALAC, and when you need that music the computer decodes/unzips it to the original uncompressed state.

Edited by miceblue - 2/12/13 at 3:13pm

Upsampling makes as much sense as "upconverting" mp3 to wav before playback. Even less actually, because modern DACs oversample internally and low input sample rate is a hint that they can sacrifice ultrasonic performance for better audio band performance.

FWIW, my soundcards RMAA slightly better at lower rates. Dunno if it's real or caused by some RMAA bug, but generally there is no reason for high rate capable DAC to perform worse at low rate and noise shaping could be a reason for better performance at low rate.

An exception would be avoiding OS resampler (if you can't do it any other way) or converting 44.1k to 48k on Xonars if their higher noise floor at 44.1k bothers you.
Edited by mich41 - 2/12/13 at 3:47pm

I don't see why upsampling would ever be a good thing. Correct me if I'm wrong but the only audible change that could result is the addition of aliasing.

 

On the Xonars I think that might have been just been a bit of a screw up by them them... at any rate on my STX there was no audible noise floor at 44.1.

Edited by chewy4 - 2/12/13 at 3:58pm

 

Apple has not come out with any new ideas in 5 years. Samsung is now the world technology leader. In 4 years people will start to notice that Apple is just repackaging their old tech. They are history but still cute, just like Twinkies.

B-b-b-b-but they'll have the iWatch. And then they'll make an iPad Mini 2 with a "revolutionary" advanced processor.

 

The Retina Display is actually pretty nice, but not very ideal for the hardware they offer on their computers. Ironically I'm typing this on a Retina MacBook Pro.

 

I still don't understand why they decided to make ALAC open-source....not that many people use it from what I understand.

Data compression and upsampling are definitively two different things. Upsampling can be used to simplify the analog part of the DAC, at the expense of making the digital a bit more complicated. A bit of a different story.

 

One way to achieve lossless compression is through Huffman coding (among other more elaborate and powerful techniques.) Consider a pretty stream of 1's and 0's:

 

001011100000000011010001000000110000

 

Let's take this stream for a date. Get acquainted by breaking the stream into pairs of 1's and 0's:

 

00-10-11-10-00-00-00-00-11-01-00-01-00-00-00-11-00-00

 

After first impressions, the first thing that comes to our attention is that this beautiful stream of bits is actually hollow and superficial. Too many 0's there. Lets replace the pairs of 1's and 0's by sequences of different sizes according to the following rule:

 

00 => 1

11 => 01

01 => 001

10 => 000

 

Note that less bits will be assigned to the pairs of bits that happen more often. Fondle this stream by substituting pairs of 1's and 0's using the above rule:

 

1-000-01-000-1-1-1-1-01-001-1-001-1-1-1-01-1-1

 

So, we went from:

 

001011100000000011010001000000110000 (36 bits)

 

to

 

10000100011110100110011110111 (29 bits)

 

Our 1's and 0's stream dropped 7 bits of clothes, and is now bit naked.

 

We scored. Lets be nice and help the bit stream cover up. We go from left to right. Found 3 consecutive zeros? Substitute with 10. Found 2 consecutive zeros and 1 one? Substitute with 01. Found 1 zero and 1 one? Substitute with 01. Found no zeros and 1 one? Substitute with 00.

 

I think this is right in a weird kind of way.

 

 

I own two Macbooks an Ipad#2 and 5 ipods. I use Itunes but still don't really see the imagination like the old days. I do think they have great DAP interfaces but it's all to propitiatory.

 

They will never change. I feel Samsung will have some weird cool piece of glass DAP in four years. Apple will be in the dust. They are too busy being at war with the world to make a better phone or DAP.

Well, where I live there is a Samsung store almost every 200 yards as you walk down the street in places. It's actually overwhelming. I just see them using the technology to invent a small multimedia device. Yes, I think it will have great sound quality but they will not stop there. It will be like a Touch but totally better. Wait and see in 4 years time!!

 

They have more talent I feel. There TVs and Fridges are fantastic. There laptops are great. I just see the quality. Still this is just my humble opinion after being super happy with their products for years!!

 

 

They had 1080p plazma TVs that had connections for PCs and USB stick ports which would play pictures and MP3s way back in 2010. They make smart TVs now. I just think they are cutting edge. Give em 4 more years and see what they do.