?Que? It's either Apple Lossless or 320kbps, but it can't be both. Most Apple Lossless files I have ever encoded come in around 600-800 kbps. and I don't think either Apple Lossless or 320 kbps AAC/MP3 would be very useful coming out of the digital audio port, since that is expected to be straight PCM (a.k.a. WAV).
Are you perhaps thinking of the Airport Express' AirTunes?
B
I'm talking about how iTunes encapsulates what it transmits to AppleTV (or AirPort Express)... It was my understanding from conversations with people who broke this down backwards and forwards that any bitstream larger than 320Kbps is transcoded on the fly to 320Kbps AAC.. You're right, Apple Lossless is basically AAC VBR. What happens though, since your optical input has to recognize the bitstream as Linear PCM, the file once streamed to the AppleTV is retranscoded back to 16-bit Linear PCM... regardless of the origin size (I've tried this with 24-bit LPCM audio and gotten the same result... comes out as 16-bit LPCM).
This isn't really necessarily a problem because the issues with artifacts or aliased frequencies are not a byproduct of compression or encoding... they are a byproduct of reconstruction errors at the decoding side. There are many technologies that have come into play to mitigate reconstruction errors since digital audio was being researched decades ago, and first deployed professionally in the early 1980's. So, none of these things should be of concern to you... but I'm just elucidating this because had I never told you... you would never have noticed.
Now it'll be interesting to see if you suffer the placebo effect...now that I told you, you will start hearing a difference and that difference, my friend, is only imaginary.
The only REAL discernible difference in fidelity through all my professional work with audio, I can safely say, is when comparing 16-bit Linear PCM or less with 24-bit Linear PCM. The increase in amplitude resolution is ridiculous... 65,536 possible values per quantization interval at 16-bit LPCM versus 16.7 MILLION at 24-bit LPCM.
Unfortunately, few if any recordings are ever mastered to 24-bit Linear PCM. There currently exists only one disc format that can support it... DVD-Audio. SACD performs inadequately by comparison, with a dynamic range equivalent to 19-bit LPCM at best, rendering it not worth the additional expense.
duffinator said:
My question wasn't about whether or not I can hear a difference. But it's about identifying which files are which. Certainly I'm not the only one ripping CD's at different bit rates. I started another thread a while back asking what was passed through via optical to my HT and the responders said it was the full uncompressed WAV file. If it's only 320 kbs then there is no point on ripping as WAV's as I keep all my CD's and my intent was not to backup my collection but to listen to the music on iTunes via my HT and whole house distribution.
I understand... my point is that you shouldn't have to encode them in anything higher than 192Kbps AAC at most. I can spot the very insinuation of audiophile snobbery from low Earth orbit, and as one who records, mixes and masters in 24-bit Linear PCM, I don't stand for that pseudoscientific nonsense. So I guess that was my way of firing a warning shot back across your bow... but I wouldn't go the trouble of changing what you've already encoded. It has to get reconstructed to 16-bit Linear PCM anyway before your HT can play it. I'm just saying iTunes sends it to AppleTV during streaming as 320Kbps bitstream... but then AppleTV reconstructs the 16-bit LPCM and sends to your HT over fiber. There's no reason that you'd ever know because there aren't enough errors upon reconstruction so as to be perceptible. (see my above paragraphs in response to the other poster)
I never said I unplug my ATV. MY HT is fairly complicated and I use a power conditioner/switcher to turn everything on/off including my ATV. From my perspective since there is memory in the ATV it should remember the last source used and reconnect when powered up.
What you're doing is equivalent to unplugging the AppleTV... A computer remembers settings because it saves them to preference files on quitting an application and upon shutting down the system. RAM is volatile storage. When you cut power to it, whatever it stored is gone. By switching AppleTV off hard with that "power conditioner" (a bunch of overpriced audiophile snake oil btw)... since you're not running AppleTV through any kind of power down cycle (it doesn't have one)... you're erasing that information. If the ability to shut it all off in one switch is more critical to you, then just deal with the fact that you have to reselect your stream source every time.
As for your home theater being complicated... Well, uncomplicate it. Anything that looks convoluted probably is.
TV even forgets what language and resolution it is supposed to use if I power it down hard, so I really try to avoid that.
