If it's visually the same - what does a "more robust playback" mean??

Vicmilt, there is less chance for a dropout with the dvcam, because of track width and tape speed. But DV andDVCam use the exact same format. Just different speed.
John

The only real differences between miniDV and DVCAM is you can't do audio track insert editing with the former (but who'd want to?) and DVCAM is easier to cue if you are doing online linear editing. We still have several PVW 2600 Betacam SP machines now relegated to tape logging and dump the keeper clips from DVCAM and BetaSX to BetaSP.

19 Minutes! (-:

"...more robust playback"

Sounds like a line from Sony marketing.

Not that I care to argue the point, and seeing is believing, but how do you explain the difference? For example, on the PD150 if we assume:

The camera is the same regardless of shooting DVCam or DV.
The CCDs are the same (of course)
The data should be the same, regardless of the tape format.
The compression level is the same on either tape.

So what gave you the richer blacks? What was the cause of the difference? Do you think that sony just automatically loads a new setup into the camera if you try to record on DV tape instead of DVCam?

Just curious since as far as we know there's no earthly reason for the image to look different. We'd all be that much smarter if we knew the how and why.

Rob Mack

I believe Rob was only referring to the difference in format between DV and DVCAM (as per the subject of this thread). In this comparison, the data is the same in both formats, or at least we are told it is. If they are the same then there should be no difference in picture quality. If they're not the same, then please tell us how they do differ.

As I read the scenerio it is sort of like a control test. You would have the same camera, shooting the same subject, under the same conditions. The only variable would be between Mini-DV/DVCam setting. For the hell of it just make the tape stock Sony PDVm-40N (DVCAM) and just use that as the tape stock.

From what I have understood in the past, not from people here but others who shoot for national networks, in eye tests people couldn't tell the differnece and from what they say the only way to tell the "real" difference was by looking at the signal on a scope. I have not done this type of control test but many have. Overall, like anything, the end result is a direct result of the process along the way.

All these posts from pros and still no one knows the answer!

I believe its as simple as 5:1 compression versus 4:1 compression. Most people don't see the difference, pros can pick it straight away on a good monitor. By the time it ends up on the consumer's TV I'd have to wonder, heaps of stuff goes to air now from DV.

If you really want to shoot DVCAM buy a PD250 but factor in the exhorbitant cost of batteries and a charger. Lots of wdding guys use them, still shoot in DV but then don't have to worry about tape and the customer is happy he's using a 'real' camera.

As far as I know:

It is the exact same DV stream!, you can dump a DVcam tape to the harddrive
and back to a miniDV tape, it is unchanged.
DVcam has greater cap between the blocks of data, it is safer, less chance
for dropout, DVcam mechanisms are also more robust.

I do not believe you can tell a difference between DV anv DVcam..

run

In that scenario you'd also have to compensate for changes in outdoor lighting over a 20 minute time period, as well as thermal changes in the camera during shooting.
An absolute test would be done in a controlled environment with the camera and lighting brought to full temperature before the recording began.

d1editor (who might be a troll, but maybe not) said:

> We recorded 20 minutes of each DVCAM
> and Mini DV... the blacks and chroma was
> richer in the DVCAM format

How can blacks be "richer"? I think you mean darker. But anyway - I'm willing to believe that you saw a difference - but all that means is that the camera records different blacks and chroma when in DVCAM mode. No really! :-) The DV stream is the same in Mini-DV and DVCAM recordings, only the way that stream is laid to tape is different. Honest. I've read the specs - have you? As for WHY your camera records different blacks and chroma in DVCAM mode, I have no idea - take it up with your camera manufacturer! :-) Perhaps the settings change when you change from Mini DV to DVCAM? Though I can't think why it would do this. You should at least be open to the possibility that you imagined it.

But even if you didn't, I assure you that the DV stream is the same in both tape formats. Your test isn't a truly controlled one until you transfer digital data from one device to another via firewire while recording in both Mini-DV and DVCAM format. If you do this and still see a difference between them (in the chroma and blacks), then you're imagining it. Don't feel bad - you aren't the first "pro" to imagine seeing evidence that supports your wrongly held beliefs! :-)

Of course, statistically, you're more likely to see dropouts and other similar errors in the Mini-DV copy, but that's the whole point of this thread - the only difference between them is that DVCAM is a more robust way of laying the stream to tape and hence is less likely to encounter dropouts (yes, yes, there are other advantages to the DVCAM format, but "richer" blacks and chroma are not present).

Lastly, I'm going to politely ask you to PLEASE not post arrogant-sounding stuff like:

> I have come to expect the consumer responses
> on this forum- the masses seem to have no idea
> what they are talking about!

and sarcastic straw-man arguments like:

> If I had only known tape format makes no
> difference.... thank you for teaching me
> this important lesson

All it does is add unneeded agro to the forum, especially when it turns out that you are wrong...

:-)


Skevos Mavros
mavart@mavart.com
http://www.mavart.com

Thank you, Skevos. Well put all the way around.

About 2 and a half years ago when I was reading everything I could get my hands on to help me decide which camera to buy, I read a meticulously documented and outstandingly written white paper by the world-reknowned Roger Jennings discussing, among other things, the "differences", such as they are, between DVCAM and DV formats and comparing their performance to Beta SP. One of the first myths he dispelled in absolutely conclusive fashion was that there was ANY difference between the data recorded in DV and DVCAM formats. There is no difference, or at least none that makes any difference to the QUALITY of the images captured. They utilize data streams that sample luminance and sample/caclulate chroma difference values at exactly the same frequencies and at exactly the same bit depths and use the exact same codec and level of compression to encode that data to tape. The only two differences are the aforementioned tape speed difference -- which helps ensure that a bad spot on a tape will not actually corrupt the data and cause a VERY obvious glitch or dropout because there are simply more tape particles used to record those values -- and the fact that the audio signal is locked to the video in DVCAM, thus eliminating the theoretical time drift issues that may exist with DV.

BTW, I ended up choosing the Sony DSR-300 (which uses the DVCAM format) but that had a HECK of a lot more to do with the stupendous 1/2" CCDs and 18x Canon IF lens that came with that camera as opposed to a Canon XL-1 or (at that time) VX-1000. The only reason the DVCAM issue weighed in my decision AT ALL was because the DVCAM format, and this camera in particular, offered compatability with the large shell DV/DVCAM tapes, allowing me to tape continuously for 3 hours without changing tapes. There is the only PRACTICAL difference bewteen the formats.

I have to question the true expertise and knowledge of someone who compounds the kind of unprovoked insults the original poster made with assertions of "fact" that contradict not only what every reputable engineer/authority in the field knows and/or has written about but contradicts what a common sense analysis of the two format specifications would dictate as well.

Elizabeth

I just wanted to echo the comments Skevos made regarding d1editor just so he knows how unappreciated his sarcasm on this board is. Why do some people insist on writing posts with their nose obviously up in the air and go so far as to even state they are speaking tongue in cheek to us "commoners", as if we can't pick up on it?

Great, YOU are such a pro that you and your management can tell the difference with your eyeball between DV and DVCAM. Trust me, the general public cannot. Some people I know can't tell the difference between VHS and DVD, and don't try to make a snide remark about that either, like that I need to meet new people, because we all know this to be true of the general public, they definitely will not be noticing any difference between DV and DVCAM.

Do everyone a favor and the next time some asks such a GENERAL question as "is there any *certifiable* difference between DV and DVCAM" - check your elite 20 year TV show production attitude at the door and realize your audience is mostly consumers who want to take some video of their kids, and answer the question as it was asked - generally...

"I read a meticulously documented and outstandingly written white paper by the world-reknowned Roger Jennings.."

Hi Elizabeth,

I did a search on itpapers.com (which is a great source for white papers in general) for this document but couldn't find it.:-( Would you happen to have a copy of it, that you could share?

Thanks,

Shawn

DV CAM VERSUS DV FORMATS - Sony TechPort Article, from http://www.taperesources.com/useful_info.html#article4

"DV CAM and DV tape compared

Cassette memory. IC-equipped pro models offer four times the memory of consumer models.

Durability. Pro media has an optimized DLC layer and surface treatment. This improves performance for editing and long-term archiving.

Dropouts. Controlled surface finishing helps cut DV CAM tape dropouts in half, compared to consumer DV.

Interchange. Tighter slitting tolerances mean DV CAM tape works almost flawlessly when recorded on one VTR and played back on another.

Shrinkage. DV CAM tape cuts dimensional shrinkage in half, an important benefit for archival stability.

Running time difference. DV CAM machines use a transport speed
faster than DV machines. So you'll experience differences between the marked and actual recording times. For example, a 60-minute DV cassette holds only 40 minutes of DV CAM footage"

Okay, cowboy, you've been doing this for 20 years, so I'm going to give you an old-school pass for today.

DVCAM and DV/Mini-DV are 1/4" wide, metal-evaporated, 25mbps (5:1) formats that record and play exactly the same video streams. For 525/60 (NTSC), both are chroma sub-sampled 4:1:1. For 625/50 (PAL), both are 4:2:0.

The advantage of DVCAM is that the recording *is* more robust. The tape speed and track width are increased in DVCAM, leading to better protection against tape degradation. Some could argue that the higher tape speed could cause higher physical failure rates in DVCAM, but I honestly don't care.

I’m not saying that the parties involved in this test compared with their heads, rather than their eyes, nor am I saying that a solitary piece of anecdotal evidence fails, in any way, to controvert the stated specifications of hardware and media manufacturers. In specification, though, there is no difference between the digital signals that come from DVCAM and DV/Mini-DV recordings.

Yo, expert: How come median is so slow?

(to D1)

Whoa... Did you forget that YOUR TV/professional audience consists mostly of consumers? Honestly, Any one of my clients could care less what equipment the project was shot on, as long as they are satisfied with the outcome and your ability to do it. If I mention DVCAM, they have no idea what the hell I am talking about. I am sorry, but the lines between "professional" and "pro-sumer/consumer" projects is blurring everyday...technology is wonderful.

PS(Creativity is even more wonderful, it doesnt matter what equipment you have, if theres a will theres a way...this is an entirely different subject)