Mini DVCAM tapes?

Trent O Connor · April 24th, 2003, 08:38 AM

Reading one of the posts:

'use Sony Premium miniDV and shoot DVCAM'.

What does that actually mean? I use mini dv tapes but whats shooting in DVCAM?

Also, do you lose any quality using the long play option on a tape?

Garret Ambrosio · April 24th, 2003, 06:53 PM

Trent, remember these are all zeroes and ones being recorded so that the material of the media will not really have an impact on the video quality, with the exception of maybe drop outs, if using a real bad tape. DV and DVCAM are formats and MINI DV is the physical type of tape(media). So they are saying if you buy the DVCAM tapes, shoot using DV (setting on the cam) in order to get more shooting time on the DVCAM tape.

The loss in quality, I'm not too sure about, but it may deal with the change of bit rate or the increase of compression applied to the video. I guess using LP, may utilize a higer compression rate in order to fit more video.

Jeff Donald · April 24th, 2003, 07:31 PM

The DV format (including DVCAM) uses 5:1 compression. The tape length is the same, but the speed the tape moves across the video heads changes. If you slow the tape speed down, you can record longer. However, tracking and playback on different machines can be problematic. It is best to avoid LP speed if at all possible.

Garret Ambrosio · April 24th, 2003, 07:46 PM

Jeff how then can the data rate stay the same if the tape is playing slower? Not being a smarta$$, I'm curious...If the file size will ultimately be the same how can the data rate not change if the physical tape is moving slower?

Jeff Donald · April 24th, 2003, 08:01 PM

The tracks that contain the data are written closer together. The guard bands (blank space between tracks of data) become narrower. That is what make tracking more problematic. The head must now nearly perfectly align with the data track. Even slight misalignment can cause error correction to kick in and degrade the picture

Garret Ambrosio · April 24th, 2003, 08:27 PM

Great explanation, I got it now. Sorry for postulating inaccurate data, but it made sense...right? Anyway, thanks Jeff. Lastly, wouldn't narrower=greater possibility of dropouts

Jeff Donald · April 24th, 2003, 08:37 PM

Yes, the greater the likely hood a spec of dust would cover a data track as opposed to a guard band.

April 24th, 2003, 08:38 AM	#16
Trent O Connor Regular Crew Join Date: Apr 2003 Location: Hertfordshire, UK Posts: 94	excuse my ignorance Reading one of the posts: 'use Sony Premium miniDV and shoot DVCAM'. What does that actually mean? I use mini dv tapes but whats shooting in DVCAM? Also, do you lose any quality using the long play option on a tape?

April 24th, 2003, 06:53 PM	#17
Garret Ambrosio Major Player Join Date: Mar 2003 Location: Vallejo, CA Posts: 263	Trent, remember these are all zeroes and ones being recorded so that the material of the media will not really have an impact on the video quality, with the exception of maybe drop outs, if using a real bad tape. DV and DVCAM are formats and MINI DV is the physical type of tape(media). So they are saying if you buy the DVCAM tapes, shoot using DV (setting on the cam) in order to get more shooting time on the DVCAM tape. The loss in quality, I'm not too sure about, but it may deal with the change of bit rate or the increase of compression applied to the video. I guess using LP, may utilize a higer compression rate in order to fit more video. __________________ "USA Today has come out with a new survey - apparently, three out of every four people make up 75% of the population." -David Letterman

April 24th, 2003, 07:31 PM	#18
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	The DV format (including DVCAM) uses 5:1 compression. The tape length is the same, but the speed the tape moves across the video heads changes. If you slow the tape speed down, you can record longer. However, tracking and playback on different machines can be problematic. It is best to avoid LP speed if at all possible. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

April 24th, 2003, 07:46 PM	#19
Garret Ambrosio Major Player Join Date: Mar 2003 Location: Vallejo, CA Posts: 263	Jeff how then can the data rate stay the same if the tape is playing slower? Not being a smarta$$, I'm curious...If the file size will ultimately be the same how can the data rate not change if the physical tape is moving slower? __________________ "USA Today has come out with a new survey - apparently, three out of every four people make up 75% of the population." -David Letterman

April 24th, 2003, 08:01 PM	#20
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	The tracks that contain the data are written closer together. The guard bands (blank space between tracks of data) become narrower. That is what make tracking more problematic. The head must now nearly perfectly align with the data track. Even slight misalignment can cause error correction to kick in and degrade the picture __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

April 24th, 2003, 08:27 PM	#21
Garret Ambrosio Major Player Join Date: Mar 2003 Location: Vallejo, CA Posts: 263	Great explanation, I got it now. Sorry for postulating inaccurate data, but it made sense...right? Anyway, thanks Jeff. Lastly, wouldn't narrower=greater possibility of dropouts __________________ "USA Today has come out with a new survey - apparently, three out of every four people make up 75% of the population." -David Letterman

April 24th, 2003, 08:37 PM	#22
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Yes, the greater the likely hood a spec of dust would cover a data track as opposed to a guard band. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors