capturing - lousy quality or huge files

[paul_999]

Thanks rsquirell. My biggest concern is losing data during the transfer.

Your comment about a short cable is well taken (I'm an electronic enginner by training). Firewire 800 should be better, not only x2 faster but its designed for much longer distance.

At Firewire frequencies (400Mhz) the quality of the cable is v.important - any impedance mismatch will cause reflections and ringing on the digital pulses with a slight chance that a few 1s become 0s or 0s become 1s.

Do you think the poor quality problems are mainly due to slow mpeg compression of busy scenes, hence dropped frames?

[atifsh]

Originally posted by xirurg
I have a firewire, but I need something stronger - some card with hardware abilities which will help my PC to capture well and fast from my dv cacorder. - could you suggest me some?

get card from snazzi,
1: 1394 instant dvd (a firewire card with hardware encoder for mpeg1/2 ) round 50 - 60 $

2: Snazzi's firelink (or somthing) again with hardware encoder for realtime hardware mpeg1 or mpeg2 encoding. 100 $ or less.

3: Snazzi III AV.DV both analog and digital card with hardware mpeg1/2 encoding round 200 $

https://www.snazzi.com

[atifsh]

Originally posted by paul_999
I'm a bit concerned reading messages about poor quality and frame skipping.

I want 100% DV quality capture exactly as per the camera tape with nothing lost. In other words a binary copy of the tape onto the PC.

Will this be ok?:
huge disk at least80Gb, 7200rpm
at least 2Ghz cpu
firewire port
capture direct to a .dv file NO compression
edit the huge .dv file in full DV quality
finally write to a DVD where I expect top quality, almost as good as camera playback

Of course good quality camera work is a pre-requisite.

exacltly thats what i dont get, if the final step is to get a dvd mpeg2 file why not make realtime mpeg2 saving time and harddisk space ?

check my other post for how ...!

[atifsh]

Originally posted by rsquirell
By going thru the firewire you keep DV resolution (720X480) intact for a much clearer image. When you capture DV with a card or external hardware device (designed for and necessary for VHS capture) the video is converted by the hardware to VHS resolution (356X240)..

not entirly true,
u can capture mpeg2 in full dv resolution. for that u need a firewire card that can do hardware encoding to mpeg2. thus allowing slower pcs to do realtime capturing from dv to mpeg2.

[rsquirell]

The DVC-150 is an external hardware device which captures in MPEG2 at 720X480 resolution....but since it was designed to capture VHS tapes the video in ports are designed to recieve VHS resolution (356X240) and will convert DV automatically to that before reconverting to DVD resolution. I know nothing about your Snazzi AV.DV card...if it keeps DV as DV it sounds interesting....but being a notebook guy, I'm limited to external devices. If DV is captured thru the firewire by ULead VS7 it remains DV resolution as VS7 automatically converts it to MPEG2 of the same resolution. I haven't heard of this processing being the cause of dropped frames...that problem has usually been corrected by improving the data transfer (ie. short GOLD firewire cable.)

[paul_999]

Originally posted by atifsh
why not make realtime mpeg2 saving time and harddisk space ?

I have to admit to being ignorant of editing. A colleague said that editing of mpeg2 had to coincide to key frame boundaries which only occur every few seconds. Hence I assumed you had to edit in a raw format to get full flexibilty of the time line.

But it looks like I'm wrong so thanks for helping me learn something today!

[atifsh]

Originally posted by rsquirell
The DVC-150 is an external hardware device which captures in MPEG2 at 720X480 resolution....but since it was designed to capture VHS tapes the video in ports are designed to recieve VHS resolution (356X240) and will convert DV automatically to that before reconverting to DVD resolution. I know nothing about your Snazzi AV.DV card...if it keeps DV as DV it sounds interesting....but being a notebook guy, I'm limited to external devices.

yes my card and some other frm snazzi do capture at full DV resolution. they also make some pcmcia cards and some expensiv external devices too for notebooks.

my friend just got new firewire frm snazzi with hardware mpeg encoder dam thats nice card and cheap too 60$ i guess, compared to my 200 $ EEEEEEeeewwww that only adds analog inputs to digital.

Originally posted by rsquirell
If DV is captured thru the firewire by ULead VS7 it remains DV resolution as VS7 automatically converts it to MPEG2 of the same resolution. I haven't heard of this processing being the cause of dropped frames...that problem has usually been corrected by improving the data transfer (ie. short GOLD firewire cable.)

yup that do fine too unless u do non realtime capturing of mpeg2 at full dv and as i remember VS7 capture in non realtime so no problems should happen.



{rsquirell, how short this gold firewire cable is? and how much ? i was thinking of changing my cable to a shorter one too but cant find anyother wires here. perhaps i should ask someone to get it for me.}

[rsquirell]

Sounds like you've got a neat card atty....my cables are 3 feet. I first learned of wires when I had a Recreational Vehicle and installed a 2400Watt DC/AC converter to run my fridge while on the road. I wasn't getting half my wattage...and the Tech Support guy for the converter insisted I install the box no more than a foot away from the storage battery and use cables so large they barely fit in my terminals. When I moved the box closer the change was dramatic and I got full wattage. There is a lot of loss in wires.

[xirurg]

thanks - rsquirell, atifsh and paul_999 - you've helped me a lot. I'll concider everything said here..
Thanks again.

[rsquirell]

"our Pleasure"

[paul_999]

rsquirell - your fridge is a good example of current problems. 2400 watts is 200 amps at 12 volts. Thats the sort of current (measured in amps) that a car startor motor takes - hence the need for seriously heavy and short cables, like those you see under the hood.

Firewire is more of a voltage thing as the current is very low. The 400Mhz voltage slowly gets corrupted along the wire. The longer the wire the more the corruption.

400Mhz is 4 times greater than a 100.0 FM radio station, and you know how a radio station fades a long way from the transmitter and eventually dissappears into the noise. In the same way a really long Firewire cable could seriously distort the DV signal and make it loose frames.

So a shorter cable gives a stronger signal with less chance of noise or corruption - just as driving closer to a town gives better reception of local FM stations.

It would be worth checking the internal wiring of a Firewire socket on the front of a case. It should have good quality screened cable like the external cable - loose wires would not be good enough and may pick up interference inside the PC.