Jumpy Monitor

eopco wrote on 6/20/2002, 2:06 PM
Hello:
I am trying to run an external monitor for video playback. I'm using a Canopus ADVC-100 video out to a regular TV. I am using the external monitor tab. The problem is that the video is jumpy. Kind of like a live broadcast from the Space Station. Is there any way I can get smoother playback through an external monitor? Any help would be appreciated.

Thanks:

Rich Krents
EOP Recording Co.

Comments

Chienworks wrote on 6/20/2002, 2:22 PM
Is that jumpy spatially (as in it moves up, down, side to side) or jumpy temporally (as in it skips frames, halts, pauses)? If it's the former then i can't tell you much except maybe check the horizontal & vertical hold on your TV because the Canopus box might be putting out a signal somewhat different that what you get from cable, VCR, etc.

If it's the latter, then keep in mind that the preview can only run as fast as your computer can process the frames. Most any computer in the 700MHz P3 class or better should be able to play a single DV track at the full 29.97fps. If you have any effects, crossfades, multiple tracks, etc, then the frame rate will slow down as more processing is required. You may not notice this much in the little preview window on the computer monitor, but it can become very apparent on a big TV screen.
Maverick wrote on 6/20/2002, 4:54 PM
Reading the VV manual I am under the impression that the only way to view from the timeline is using the firewire connection to DV in and using throughput from that to TV/video. Until then I was under the assumption that you could simply connect the TV to the TV Out of your Video card. Could someone please clarify this point.

I haven't attempted this as I was afraid of messing about with settings, refresh rates, etc.

Cheers
SonyDennis wrote on 6/20/2002, 5:04 PM
DV out is the cleanest way. You can use the video out found on some graphics cards, but you're not running true NTSC colors, frame sizes, or interlace characteristics, so it's just an approximation.
///d@
eopco wrote on 6/20/2002, 5:39 PM
Sonic Dennis:
I am running DV out through the Canopus box. Is my problem my computers processing speed as mentioned a few post's back? If so, how powerful shoud my computer be to get clean external monitoring. This is very important for I have clients who do not want to see a tiny video prewiew on my computer.

Thanks for you help in advance.

Rich Krents
EOP Recording Co.
SonyEPM wrote on 6/21/2002, 8:52 AM
rich krents- feel free to email me offline, drdropout@sonicfoundry.com
SonyDennis wrote on 6/22/2002, 12:49 AM
Rich:

Sorry, my previous reply was to someone else asking about Firewire out vs. dual monitor video out.

I'm sure SonicEPM will get you up an running, but the short answer is: for unprocessed DV (no FX, transitions, pan/crop, track motion) you should get realtime playback via Firewire. Processed video will require on-the-fly rendering, so you'll drop some frames while it does that. You can easily pre-render a section (a transition, for example) and then that section will play back in realtime. The pre-render will stick around unless you make changes to the transition settings, and the it will go back to on-the-fly rendering. Note that a lot of other NLE's require pre-renders to see anything on external monitor, Vegas let's you see changes as you make them, it just drops frames as necessary to keep up. With a fast processor, that's often not a problem either.

///d@
HeeHee wrote on 6/25/2002, 1:05 PM
I have a similar problem to the one eopco is referring to. However, mine is not as a result of CPU performance. When I have an external display hooked up to my ADVC-100 the preview looks fine as long as it is playing. If the image is paused or I am stepping thru the frames, the image on the ext display tends to jump up and down a bit. Is this a frequency issue or something else, what?
SonyDennis wrote on 6/25/2002, 2:55 PM
When you're playing, the system is outputting every field. When you pause, just one field is shown, otherwise your still image would twitter. When you step by frame, it's switching into "both fields" mode for one frame, then back to "single field" mode, and the jumping you are seeing is the second field. Backward steps are going to look jumpier than forwards steps becase the fields are shown in their usual temporal order, but you're moving backwards throught the video, so objects will move as B/A/D/C/F/E instead of A/B/C/D/E/F (where letters = position).
///d@
HeeHee wrote on 6/25/2002, 4:55 PM
OK, so what you are telling me is that this is normal and there is nothing wrong my A/D converter or how it is setup. Right?
SonyDennis wrote on 6/25/2002, 8:32 PM
Right :-)

The jumping I'm referring to is based on interlace scanlines. If you're seeing multiple lines of movement, then something is wrong. But single scanlines of jump are expected due to interlace.

///d@