Axiom Home Page Forums General Discussion Technical Questions Itunes, bitrate, and other questions...

OK, so I started using Itunes recently. Yes, I know...get with the 2000's Randy, lol.

Anyway, I am planning on buying an external storage drive to store my CD's, Vinyl, etc. If I use a higher bitrate or lossless format for my local Itunes copies for the best quality when playing over my M80's, can I synch easily to a portable device (Ipod, mp3 players) in a lower bitrate to save space on the device? I see where I can experiment with various encoders and bitrates in Itunes, but can't see where the import bitrate setting would be different than what I put on a portable player.

One way is:
1. Import first in lossless.
2. Change the import settings for a lower bitrates.
3. Right-click on your songs and select "create MP3 version" (or whatever the format you choose).
4. Itunes will create a copy.
5. Rename the album of the new tracks from "Regina Specktor" to "Regina Specktor (ipod)"
6. Create a "smart playlist" called iPod for all "albums" contains "(ipod)"
7. Select "manualy sync" when syncing your iPod and select the "iPod" playlist.

This sounds like a lot of work, but it is actually not that bad and you do it only once.

That does not sound to bad Eric, so by doing this I will have two copies on my hard drive, one lossless (or higher bitrate) and one at the lower bitrate that I synched to the Ipod?

Or, is there some way when you make a copy to have it copy to the IPOD, or can you drag/drop? Just looking for options.

I was thinking about using MP3 320 CBR for my main copies, as from what I have read in blind tests, most people can't tell the difference between anything above 256 and CD quality.

For the Ipod copy I would probably use 128kps VBR

Is lossless "really" lossless?

Just a general question.
I've had some discussions with some rather brilliant computer engineers and programmers (you know, the kind of guys who learned how to build circuit boards at the age of 12) simply stating 'any compression format can be assumed to induce errors by its very nature of how they compress data'.

if the original waveform can be reconstructed, then it's lossless. I've never seen an error analysis for any lossless format, though.

CV bait.

I don't know what those guys were doing, but at 16 I was designing lossless packing algorithms for 2D graphics. I know for a fact that RLE (run length encoding) and dictionary pattern matching are lossless. They are also blindingly obvious, and a 16 year old could come up with them on his own.

Lossless audio is somewhat more complex, but I still have no doubt that it can be done without introducing error. One of the usual methods is to write an prediction algorithm which tries to guess what value will come next based upon previous. If it's right, then nothing needs to be stored. If it's wrong, then the difference between the predicted value and the actual value is stored. The error is the data.

Properly implemented, there are many ways to reduce the redundancy in data, that when undone presents an exact copy of the original. One thing, in packed form damage to the data will be more extensive when unpacked. But that's not a failure of the compression, but of the transmission/storage medium. And why we have error checking and correcting.

They were talking about lossy encoding. 'by its very nature' zipping remains zipping while 'by its very nature' jpg/mp3 loses data. How much data did you loose so far with zipped files? If any, it was the result of hard drive failures, not the unzipping process.

Any other input on my questions.

Eric's method is what you're going to have to work with. If (and unfortunately only if) you're syncing songs to an iPod Shuffle, then iTunes offers an option to convert songs to 128 kbps AAC on-the-fly.

I find it interesting that there is no way to just highlight an album and export/copy it at a lower bitrate to your mp3 device, without leaving an extra copy on your hard drive. I will have to play around with it some more, thanks for the help..

Eric, I just read an article about having more than one Library in Itunes. In windows, if you hold down the Shift key when launching Itunes, it gives you the option to create a different library, and which library you want to launch.

If I create a seperate library for my lower bitrate stuff, is there an easy way to create the copy into that new library from the other library?

There isn't an easy way to copy files from one library to another. You can duplicate your entire music library, but then you still have to convert all the songs in one of them and throw out the lossless files.

And then, you'd have to manually manage new songs you import between the two libraries.

iTunes is nice, but it wasn't designed to do what you want it to.

I would not trust that option. With iTunes, the more you "see" what you do, the better. The playlist option is, as far as I know, the safest way to go.

I believe Media Monkey can Compress music on the fly when transferring it to the ipod.

Thanks guys, sounds like keeping everything in one library and using "smart" playlists might be the best option. I guess I will have to have duplicates of every song at two different bitrates then...

Unfortunately i cannot reproduce the conversation as i was merely a spectator and the language was beyond my knowledge base, but it does sound similar to what you are speaking of; the concept of prediction algorithms and how effective that is with the complexity of the audio range in a digital recording.

Does a 450.1 Hz tone get assigned the same compressed digital tag as a 450.001 Hz tone because they are 'close enough'?
Does a 560 Hz tone 1 second long get the same compressed hexadecimal digital tag as the 561 Hz note only 0.001 seconds long that follows it because the person writing the compression algorithm would 'know' that any note less than x seconds could not be interpreted by the human brain anyway?

This is a terrible example i realize, but if i understand their conversation correctly, that was the gist of the argument, that data could still be lost because of the predictive nature of the compression algorithms.

I think it would really depend on how big the iPod was and how long you needed it to play for (or what variety you'd want). If you got a 8 or 16 GB iPod (not to mention one of the HD based models at 80 GB or so, who cares if you're using uncompressed music on there and the files are huge?

I keep all my music at at least 160Kbps, and now I do it at 256Kbps VBR AAC--and I use a 20 GB, a 30 GB, and a 2GB iPods. Plenty of music, even on the 2 GB one.

With lossy encoding, what you're saying can sort of happen. MPEG audio uses a cosine transform. It basically takes the time-domain sample rate, and converts it into frequency domain. It than can analyze that frequency information, and try to find slices of a cosine wave which fit the original wave form. This Fourier transform in theory can be lossless, but it would take an infinite number of slices to completely reproduce an original analog signal.

Luckily CD audio has only 44,100 samples a second (time domain), and when converted into the frequency domain the highest frequency which can be reproduced is 22.05 kHz (Nyquist limit). So using 22k cosine slices for every second of audio would be able losslessly recreate the original PCM (within some very small margin of error). In practice that's a worse case, and one can get by with many less pieces and still have near lossless encoding.

But the problem is storing that many cosine coefficients would take more room than the original 2-byte (16-bit) samples. So in order to get the 10:1 compression which is common from MP3s, even fewer slices are used. This only gives a rough approximation of the original waveform. Fine details (like high frequency information) gets smeared together, and large rapid changes cause pre-echos or ringing.

None of this applies to truly lossless encoding schemes. They may use some perceptual estimation routine (DTS does this, Dolby's MLP along with FLAC use strictly numeric prediction) for the initial data reduction. But it goes one step further, and then checks this estimation, and looks back at the original recorded value. If there is any difference that's stored too. So as the final decode is done by the player/receiver it comes up with the estimated value, and then applies any correction to get the exact original data back. There's no loss or error.

Yeah, if it's already in the digital domain, it's easy to compare the compressed with the uncompressed on an exact level--the computer can just uncompress it to check!

As long as it's in the digital domain, the computer doesn't think about it in terms of length of the note or tone--it's all just bits.

Bonus points to anyone who can explain what FFmpeg logo means. (Yes it's on-topic to my off-topic topic.)

uhh, it's a green waveform?

No waveform function can have two different Y values for one X. So it's not a waveform.

Another hint: It has to do more with pictures than audio, but is still related.

And here I was thinking it was rotated 45° so it would fit in a square better...

Fitting in a square; that's actually pretty insightful.

I'll give.

The Fourier transform can only be applied to 1 dimensional data. The change in amplitude of audio samples over time is what is fed into it for MP3s. But pictures are 2 dimensional. So what JPEG did was to break each picture into squares, 8x8 being the most common. Then they needed a standardized way to linearize the pixels in that block. Keep in mind the Fourier transform works best when the next sample fed into it is closely related to the previous. So what's the path through an 8x8 grid which most closely relates each next sample to the previous.

There's your answer!

Watch out, or Tom will banish you to the math thread.

There's a Math thread?!

Would you guys stop copying/pasting Google search results to make you sound smart. lol

I've known the fact about the JPEG/MPEG macroblock encoding path since 1992 (got a copy of Micrografx Picture Publisher which included this new JPEG image format and I had to know how it worked). When I saw the FFmpeg logo I was so overjoyed that I got it. Been wanting to share that bit of info with someone for a couple years now.

Now if only you'd share the fact that you're bbigwyres or however you spell his name.

Wouldn't that be the ultimate irony. But nope. I don't like his posts, they hurt my head.

Now this is starting to sound alot more like the conversation the other night though there was alot more talk about hexadecimal coding and compression by data prediction and algorithmic math.

As Ken says, and it does seem rather obvious when you take a step back, the data on a cd is already in bit digital format so it seems easy to reproduce that original code again with error checking after decompression.

Where the hell were you boys the other night when this conversation was happening? Over 7 bottles of various French red and white wines eh??!!!

I... don't know. I'm sorry I missed it.

Hmm, possibly because i think it was Christmas night.
Possibly...

They mostly come out at night. Mostly.

Sounds like my wife might get me a new IPOD Classic 160GB. With that in mind I will probably rip my CD's to an external storage device using Apple Lossless, and then follow Eric's instructions to create smaller AAC files for the IPOD.

I am curious what others are doing.

I went through this agony a year ago. Or maybe it was two years….. 900 CD’s ripped. It was a slow and painful process. If you are going to rip your collection, you might as well do it right the first time, get them on your hard drive, then you can screw them up at your leisure. Just make sure you keep the original rips somewhere that you can keep the folder unadulterated.

I would highly recommend you rip them to FLAC first. After trying several different programs, I sure wish I would have just used DB Poweramp first. It will rip to two different bit rates and dump them into two separate folders at the same time. You can set it up however you wish. Warning: be sure you have your options set up for tagging as you want them to be recognized the way YOU want them filed and not the software defaults first. If you don’t, you will forever be trying to fix them. Another plus for DBPoweramp is that it will grab album art as you rip. Many don’t, and it’s very, very difficult to find artwork after the fact unless you enjoy more pain to find each album one at a time. I’ve tried several batch gathering tools to find the art work, and none work. iTunes does, but it won’t share them with other programs……

So after you get them ripped, I would do as I did. Buy an HP smart media server and store all your music files on it. They are cheap now. I installed Squeeze Box onto the server and I use the Squeeze Box Duet to talk to my home stereo. I listen to the FLAC rips with the SB.

For my iPod, I have the 320K ripped songs that are in a separate folder. I point iTunes to that folder.

iTunes does not like to play with other programs, so you will always be wondering just what in the heck happened for one reason or another.

If you are interested in doing this, just let me know and I’ll go into more detail.

Thanks Mike...

If it was a 160GB, I'd probably rip it as ALAC and just use that on the iPod. That's over 400 albums worth in lossless--how much music do you need with you at any given time?

Yeah, I can't imagine wanting to take my whole collection with me in a portable device, unless I become a hobo.

I'll echo everything mike said. I'm fixin' to rerip everything to flac with db poweramp and am looking forward to having art.
Inconsistant metadata will really screw with you later if you don't get it right when you rip, so pay close attention to that.

An altenative to itunes I use is anapod explorer

I really want one of those. I'm going to buy one after I build my new computer. I wonder when they'll have a new version.

They just released one a few months back. We have it at the office. It's pretty good, but it does run a fair amount of HP crapware--some of which does stuff you might want. We also have a virtual one that's much more lightweight.

What does the HP media server do that a computer with the right hardware and software can't?

Heck Charles, why not make sure your new PC can do all the media serving you need when you build it?

Not a whole lot. In fact, nothing. It also has no monitor, no keyboard, and no mouse, so the only way to hit it is via RDP. It has handy removable hard drive bays, and it probably uses a lot less power, but that's about it.

Being able to get to a machine via RDP is nice; being required is a pain. My home computer has handy removable hard drive bays, 8 of them, which take SATA or SAS. Know what uses less power? Not having a second machine at all. So it's neat, and has a market, but for someone who's at least a little computer savvy: not much point.

Well, I don't necessarily want my computer on all of the time, and it would be nice to automatically back up my computer to it, as well as my parents' Macs, which are on the network. It seems like it would be a lot easier for me to get one of these than to try to en-savvy myself.

Oh, you turn your computer off? How do you deal with the wait when you need to come post here? But yeah, if you don't leave your PC on all the time, having a low-power server would be nice. Also the central back-up is a plus when multiple machines are involved (I try not to involve myself that way at home--get enough of that at work). Still, I'd put together a purpose-built machine before I'd buy this, but that's me.

I'm not so confident in my ability to do that, and the price doesn't seem outlandish with how much pain it saves me. I'm still curious, though. Off the top of your head, what would your purpose-built machine consist of?

I went with the server because I do not want to have to use my office PC to enable the use of the Duet Controller / Squeezcenter. In fact, I do not want my stereo system(s) to have anything to do with my PC. My PC is for work related stuff, screwing off on the internet and photo processing. The server just sits there humming all day, every day, 24 hours a day with Squeeze Center running in the background waiting for me (or anyone else) to grab the controller and hit play. We can select my music collection, internet radio, Pandora, Rhapsody or any of the other music services I have. The Duet, by far, is the coolest Audio toy I have. Every time I show it to someone, they want me to right down everything they need to buy. I can not recommend this set up enough. I seriously doubt you will find many folks who have done this who wouldn’t.

I am not PC literate. It is a means to an end and I swap them out every two years. I want it to be disposable. To be perfectly honest, I hate the damn things. I hate software, I hate constantly having to screw with updates, worry about viruses, deal with ‘issues’ that come up…… I just hate them. However, I am aware that they are a necessary thing in every day life and I try to adapt. But – I refuse to keep the PC as my center of life and the server assists with that small piece of mind, although it’s mostly illusionary.

One other advantage with the server is it has lots of space. I have an older generation that came with two, 500 gig drives. I have since bought two additional 1T drives, so now I have 3T storage on the server. All my music is on it, and I back up all my photos to the server, which are on their own external drive. I really like the idea that the only files on the server are my music and photos, which just happen to be the mot important files I have. (and I have one drive that backs up the other drives for double redundancy).

Just a quick off-the-cuff build idea:

Zotac IONITX-F-E motherboard; I love these boards, they're low power draw, but pack a lot of punch. This one has a 16x PCIe slot. Into that I'd put a SATA controller with at least 8 ports. What ever case and power supply you want. Even though that board is a mini-ITX, it's screw holes match up with ATX so it can be used in normal cases. I'd go with something which has 8 hot-swap SATA bays, and an open 5.25" bay for an optical drive. The onboard SATA would be for the optical drive, and I'd probably put one fast (SSD if you like) boot drive in for the OS, leave the hotswap bays for media. Add add the drives and some RAM, and you're done. That give you N WiFi, gigabit Ethernet, HDMI/DVI/VGA, sound over HDMI, optical S/PDIF, and 5.1 analog. Along with enough bays for 12 TB of storage today, 16 very soon.

The base system, with just the boot drive, DVD burner, and 2 GB of RAM, and OS could be had for about $700. Then about $100 for every 1 TB after that.

Yes we should talk more about this.
I've been eyeballing some solutions for sending audio to various other home stereo systems to alleviate the disc swapping thing.
I was contemplating a Sonos solution so i could also power some outdoor speakers in the gazebo but may also need to think about a solution for streaming satellite to another home office computer w/out a tuner card.

What OS would you be using, and how much configuration would it require?

Actually add another $75. I was thinking Windows 7 Home, but for its media abilities, Ultimate would be better. So, Microsoft Windows 7 Ultimate 64-bit for System Builders. Just fire up Media Player, and enable sharing. That'll give you basic DLNA streaming for MP's supported file types. If you want MKV and a few more exotics, you'll need to get 3rd party software, but that's not bad. Free gets you something OK, $30 gets you something easy to use (TVersity).

EDIT: Or you could go with the same Windows Home Server that HP uses for my original estimated price of $100 for the OS. But I'd still rather have Win7.

Why not just a cheaper NAS solution like the Dlink 323? It works with iTunes, DLNA etc., offers gigabit connectivity, can act as a print server. I have yet to set mine up.

Related question: What would you do for a Media Center Extender?

An Xbox 360. Otherwise, I'd not use MCE, and just make use of the standard DLNA.

DLNA through what device connected to my main system, though? PS3 when I get one again? I didn't really want to use my Xbox 360 for music streaming since it's converting everything to a Dolby Digital signal, right? At some point I'll have my main computer hooked up to my main system, but it will be a while. Thanks for all of the answers, by the way. If I get to be annoying, just tell me.

The newest (beta) firmware for the Oppo does DLNA now too. But yeah, the PS3 does it, I'm pretty sure the 360 also.

I wonder if the Oppo will ever get Netflix, Youtube or similar streaming abilities?

Oh, the only thing about the PS3 is that it won't play lossless WMAs, which is most of my music collection, unless a recent update has changed that. Nice to know about the OPPO.

That's where some of the fancier media server software comes in. They can transcode between formats on the fly when serving up the data. So WMA/FLAC can be served as WAV. MKV can be turned into M2TS.

On the NAS / WHS solution, i would recommend going the WHS route but agree with Chris on the build. HP box is a dumb solution. I built my own PC and installed the WHS OS on it. I got various add-ons running on it along with squeeze center and playon and torrent.

It does all my backup along with duplicating (something like Raid) and also allows me to access all my content on the web.

--Avi

BTW, i moved from the freeNAS solution to WHS and love it.
Got my WHS OS for about $40 from microsoft :-)

Having never used Windows Home Server, but the full version of 2008; what makes WHS so great for serving media files, over just a standard Windows 7? Microsoft doesn't make DLNA software which understands MKV or FLAC files do they? So you're still reliant on 3rd party software to do the serving. Windows 7 has H.264 and Dolby Digital Plus codecs installed by default, so just Haali Media Splitter is all that's needed for most MKV playback.