Is copying a JPEG onto a Music CD as good as onto a Data CD?

Question

Is there a difference in music CD's and Data CD's. Can I copy music to a Data CD. Is A JPEG photo Data, and what is CD-R or CD+R . And a 5.0 megapixel pic and a 700 megabite disc bla bla bla

Answer 1

OK, taking this piece by piece.


* Is copying a JPEG onto a music CD as good as onto a Data CD?

Could answer this in a few ways.
1/ You -can't- copy a JPEG onto a music CD. Well, you can, but all you'll get out of the other end is a hair-raising screeching noise. PCM audio only, sorry. It may start out as an mp3, or whatever else, but that's what's laid down on the disc - essentially a 44.1khz, 16 bit, stereo uncompressed WAV file of sorts.
2/ It's just the same as any other CD... the "music" discs you buy are plain vanilla CDRs, but they have a certain bit pattern in their preset formatting/structure that tells a hi-fi seperates CD burner that you've paid the extra for a "genuine" music CDR that puts licensing money back into the record company's pockets (as compensation for how you're supposedly ripping them off), and therefore it will actually work. The hi-fi device won't work with regular data/general use CDRs. PCs and all manner of CD playback devices can't tell the difference, and there definitely isn't a difference in quality... you still get awful cheap ones and good expensive ones (and the other way round o_O)
3/ If you use CD-extra to copy additional files onto a music CD, they are stored in regular CDROM format on a seperate part of the disc. There's no difference in this way to a normal CD. Except if you go in for all kinds of autoplay nonsense you may annoy someone who just wanted to put it in their drive and play some music (also, it probably won't work in a DVD drive - you'll have to make a seperate disc for music, and for pics)


* Is there a difference in music CD's and Data CD's

Again 2 ways...
1/ As stated above, a blank CDR labelled as "music" will simply cost a bit more than a data / general purpose one, and have a flag set in it's pre-burnt Table Of Contents that unlocks audio-only drives.

2/ BURNING a disc as "Music" rather than "Data" DOES involve quite a difference however. CDs were originally meant for music only, and the CDROM (data) type is a fairly different derivative of the original format. Music discs use a bare minimum of error-correction in order to make more room for sound in the same space (at their invention in 1981, they were pushing the very boundaries of electronics science in terms of usable capacity per unit area - and it was only just enough to fit a certain benchmark symphony suite within the same diagonal space as a cassette tape), and because they can get away with it (consider a scratched vinyl record or a hissy tape as a good example of the amount of corruption the human ear will "allow" in a recording before it sounds unacceptably "bad"). A few tics or other anomalies here or there after it became scratched still left it sounding a hell of a lot better than the competition. Therefore the original specification allowed about 740mb of data on the disc, to store ~75 minutes of music. (This also applies to storing video data on CD)
On the other hand, data CDs HAVE to precisely recreate the original data that was stored on them; what might be a small unobtrusive "tick" during a loud piece of music could represent the mangling of a half page of text, the destruction of an entire program or a noticable scar on an image file (or a loud, jarring artefact in a compressed audio file). Even a single character out of place could foul up a program's operation (say, autoroute deciding that the M5 motorway in britain was now called the M1 - two entirely different and unconnected roads, but possible turn-offs from the M6, which could see you getting lost by several hundred miles), or render an entire multi-megabyte compressed file largely unreadable... So, data discs have far more rigourous error detection and correction routines... I think the guy who came up with the final scheme won an award for the cleverness and efficiency of it, but still - it meant only 2048 bytes of non-audio data could be stored in the same (1/75th second) space as 2352 bytes of sound. The capacity (and transfer speeds) dropped accordingly - to 650mb, hence the once-common "650/740mb" discs (similarly "700/800mb" ones - but now less confusingly usually just referred to as 80 minute) - but the reliability is much improved. Also, as already said, an audio-format disc can store only audio (unless you're going to be really clever and find some way to store your data in sound files - and handle the disc as if it was made out of some kind of priceless gossamer) or, at a pinch, video; a data disc can hold anything...


* Can I copy music to a Data CD?

Yep. Easy one this. You can take your general purpose "data" CDR and make a perfectly usable audio disc with it for your CD walkman, or make a CDROM containing WAV files, MP3, WMA, AAC (mp4), AC3, OGG, AU, RAW, MIDI etc... Only don't expect the CDROM to play in your hi-fi! (unless you have one that can specifically handle it, e.g. most DVD drives - note, most of them only "understand" MP3). Also, the capacity will be different; slightly shorter play if you use CD-spec WAV (why would you?!), significantly longer play if you use lower quality WAV (ADPCM compressed, lower sample rates, mono etc) or of course high quality MP3 type compression.
If you want to be perverse, you can make a data CD from an "audio" CDR, then copy wav files onto it...


* Is a JPEG photo Data?

Normally. It's a "lossy" type image compression format that works best on photographic images, as it was developed and tuned for digital photographers and the press. It uses "tricks" of the human eye in regard to how our eye and brain process natural images (e.g. we actually pick up far less colour information than we think we do, certain shapes can confuse the system, etc) to shrink the image file size dramatically without making a visually noticable dent in the quality - unless you (a) overcompress it, that is "throw away" and warp too much image info in an effort to squeeze out those final few kilobytes, (b) zoom into it quite a lot, where the effects are much plainer, (c) use it on unsuitable material --- all of which is pretty similar to the MP2/3/4 audio and MPG video standards that drive the majority of our digital media business, all being developed by the same big group of technicians.
Suitable material is then photographs; often not a great amount of strong colour, usually large expanses of yellow through blue hues and smaller patches of purple or red; quite drawn out colour fades; fairly soft and flowing edges and some closely repeating patterns, little very harsh contrast areas, etc. Unsuitable material is stuff like text, line-art, cartoons, various computer generated screens (this web page would be very bad for JPG), anything with *super* fine and particularly colour detail, in a limited range of colours... better to use GIF, or preferably PNG for these, which will probably compress better, preserve the details perfectly, and not suffer nasty artefacting around hard contrast edges or sudden colour changes. (Conversely, they are pretty bad themselves at compressing photographs, as the continual changes in and wide range of colours don't lend themselves well to GIF/PNG calculations, even though it will come out looking perfect or near-perfect at the other end)

A JPEG *should* be a photograph, but it isn't necessarily "Photo data", and the same applies the other way around. It is almost certainly the data format your camera produces (unless it's a fancy expensive SLR, that can put out professional-grade TIFF or RAW images). The Kodak PhotoCD format is something else entirely - it uses JPEG at some point of it's operation, but it's a fairly altered beast.


* What is CD-R or CD+R?

A CD-R is a CDR, that is, a recordable CD. CD+R doesn't exist. You may be getting confused between DVD-R and DVD+R (bizarrely "competing" (?!?!) standards of writable DVD), or with CD+G ("CD plus Graphics" - kareoke CDs, containing the lyrics and some very basic images cleverly "embedded" into the low-speed stream of control-codes that run alongside the audio data).


* A 5.0 megapixel pic? 700 megabyte disc? (bla bla bla)

Come on, now you're just reaching, or getting too lazy to look this stuff up for yourself. The answers to these things can be found within the explanatory boxouts on electronics pages of home shopping catalogues. But just for the hell of it:

5.0 megapixel = a camera that produces images with approximately 5 million pixels each (picture elements... the little squares a computer image is built from). This is a fairly high quality image, on a par with typical 200ASA consumer (but not pro) grade 35mm film. From my own 5mp camera, this means an image containing ~2600 pixels across, and ~1950 pixels down, enough to allow full magazine quality print on a borderless letter-sized page. If you're only ever going to print a few favourite shots at 6x4 inch, or use them as desktop wallpaper, a basic 2- or 3-megapixel device will be perfectly adequate. (I often drop my image quality to 4 or 3mp if on a lengthy excursion to fit more images on the memory card... it looks about as good in the end!). For comparison, a typical modern computer screen is about 0.8, 1.3 or 2.0 megapixels, or somewhere inbetween. Standard definition TV/DVD is 0.3 - 0.45 megapixel depending on location. HDTV is 0.9 (720p) to 2.1 (1080i).

700 megabyte disc - an "80 minute" CDR that can hold (at least) 700 million standard characters of digital information... typically 703mb, or 79m59.9 seconds of audio data (as this is the maximum length the CD's basic information system allows to be pre-registered, and the data equivalent of it... in reality, you could get ~81, 90, 99 minutes and correspondingly increased data storage, depending on how far a particular manufacturer wants to push the envelope and boast... for each, you have to "trick" the CDR drive into going beyond the stated 79'59.9" capacity). Each character is a byte, or 8 bits (by-eight... its a 60's thing... 4 bits is a nybble). One million of these is a megabyte (mega = greek for million or something)... to be precise, 1048576, as it's officially 2 raised to it's 20th power, or 1024 (kilobyte, 2^10) squared. 700 of them equals an awful lot of info, anyway, or at least it used to. It'd be about 350 books with 500 pages each (no compression, no images), 70-ish minutes of CD quality audio or VHS quality compressed video, 12 hours of MP3 audio, thousands of 2 megapixel JPGs, a good many programs etc. By comparison, a standard old floppy disc is near-as-dammit 1.4Mb (500x smaller). However, they're both now dwarfed by multi-gigabyte (1024mb) USB "pen drives" (the size of gum sticks), DVDs (4480mb single, 8150mb dual layer), Blu-Ray and other next generation media (25,000mb or more each)....

Any good?

Answer 2

picture, music, other files also data. So there is no different if you copy or picture or a mp3 file or a word file to a CD or DVD or even usb flash...

Answer 3

The labels "music" and "data" don't mean anything - they're the same thing. It's a marketing gimmick.

Answer 4

Yes, you can do both. Usually at the beginning of your burn program it asks if you are creating "music" or "data." I've done both on same CD's.

Hope that helps.