GeoVision Video Source Sizes

[rory 0]

Someone mentioned on another thread about how their Denterlace was worse quality than Interlace so i post these here and you guys can make up your minds ...

 

640x480

 

640x480 DeInterlace

 

720x480

 

720x480 DeInterlace

[Aardie 0]

My Mistake Should of clicked on Deinterlace is Worse

 

Regards

 

Keith

[Jasper 0]

Also compare the file sizes between the same amount of video in both modes. When I tried it, the interlaced took up quite a bit more space.

 

Is this correct or is my memory failing me?

 

If you play it back on a TV, then interlaced would be better since a TV is an interlaced device.

 

Also still shots are not really a good way to compare. Video would be a better demo. I doubt if most people can tell the difference though. This question cannot be simply answered by a yes or no. It depends.

[Jasper 0]

Adjusted to bring out distortion:

 

Interlaced:

 

 

Deinterlaced:

 

 

Interlaced looks better in this snapshot with the detail brought out. But what are the file size differences? How many people could see that much of a difference before the images were enhanced?

[rory 0]

remember thats only a 380tvl camera also ..

[Jasper 0]

If you record 5 minutes of video using the two different methods, which one takes up the most amount of disk space? If the deinterlace method takes up much less space, wouldn't want to use it?

 

Maybe you can run that test Rory. I did it awhile back when I had a Geosystem in my possesion, but now that it is in location I can't run the test right now.

[Jasper 0]

OK, I just ran the test remotely. The file size went from 23MB for 5 minutes of video at 640x480 7fps, to 35MB per 5 minute file when switched to interlace. 480tvl camera. And that is using the Crappy FastMpeg4 codec (GEOX). The better quality compression methods are going to eat up much more hard drive space.

 

If you have a lot of extra hard disk space I would record at whatever looked the best, but as we know, that is a lot of hard disk space.

[rory 0]

25MB file ...???? Did you set it to continuous record mode?

 

[edit] just saw the 7fps ...

[Jasper 0]

Yes, that is at continous record mode at 7fps, using the FastMpeg4 (GEOX) codec.

[rory 0]

Yeah I just did a test

 

200MB, full 25fps 720x480 De Interlaced - 5 Minutes

187MB, full 25fps 720x480 Interlaced - 5 Minutes

[Jasper 0]

You got the opposiite results though, weird.

 

Your interlaced file was smaller than the deinterlaced video file? Not that much difference either in your test?

 

What is going on here? Is this the 380tvl camera again?

Edited February 24, 2006 by Guest

[rory 0]

Light changes in the video due to cars passing ... effects the size of the images.

[Jasper 0]

one of the other cameras went from 83MB deinterlace to 131MB when switched to interlace. Big difference in this situation. If your file sizes are not substancially increasing then interlace would seem to be the right choice for you.

 

Your test results must be varying greatly because your testing with a 380tvl camera and I am testing with a 480tvl camera? Plus your recording at 720x480, whereas I am recording at 640x480.

[rory 0]

Deinterlace (googled)

 

This is the process of creating a single frame from the two interlaced fields of a video frame. While interlaced video can look much better on a TV screen, on a monitor it can look rather bad.

 

 

also see:

http://www.100fps.com/

[Jasper 0]

Deinterlace (googled)

 

This is the process of creating a single frame from the two interlaced fields of a video frame. While interlaced video can look much better on a TV screen, on a monitor it can look rather bad.

 

 

also see:

http://www.100fps.com/

 

Yes.

 

That is why I said this is not such a simple question to answer. Much depends on all of the variables involved with the encoding and decoding of the video and the playback device that is used to view the video. You really want to go crazy read that sight you just sent me too.

 

 

So interlacing is in fact a clever way to compress a movie when one cannot use digital compression methods. Interlacing reduces the bandwidth (= storage space nowadays) by half, without losing vertical resolution in quiet areas (in motion areas you don't notice very much anyway, because it's moving 50 times per second). So interlacing is a way to display the nonmoving parts with full resolution and the moving parts with half resolution, but fluidly. It's a very clever way to cut bandwidth without sacrificing much quality. BUT: You have to deinterlace the right way.

 

What is confusing is that my testing is showing that on this GeoVision setup, files created using the deinterlaced method are producing much smaller files than the interlaced method. Usually bigger files means better quality due to less compression being used. But the above statement does not match my testing results, which are the interlaced files are bigger, not smaller than de-interlaced files. This must be due to digital compression method being used in this case.

[Jasper 0]

NEVER BE FOOLED: If you see just one single frame instead of the whole video to show you the quality of any deinterlacing method, be aware. You won't know how good or bad it really is.

 

NEVER.

 

Because you don't know how fluid the video plays and how many fine structures are lost and whether the deinterlacing method still fails sometimes or leaves interlaced lines.

Instead, compare the deinterlacing methods by watching one minute or so of both videos with still and fast moving scenes. How fluid is it? How blurred is it? How many interlacing artifacts are left?

 

Source: http://www.100fps.com/

[CollinR 0]

640x480

 

640x480 DeInterlace

 

720x480

 

720x480 DeInterlace

 

 

 

Is it just me or doesn't every single image market "DeInterlaced" looks all interlaced to hell. I mean the curb at Rory's house looks like stairs! That hasn't been deinterlaced properly, then the supposedly interlaced images all look smooth. That curb isn't moving, no need for that.

 

Think this might be a labeling issue?

 

Does geovision require WMP to be installed? If so I have had loads of issues like this with different captured video. WMP does not read the DAR (display aspect ratio) and will make assumptions. I would be willing to bet it would look at that as 720x480 anamorphic widescreen and stretch it to 853x480 like it would 16:9 widescreen DVD MPEG streams.

[CollinR 0]

You could do this test better with a cam close up on slowly spinning fan black blades in a white room.

[CollinR 0]

I'm not sure you would need to deinterlace it anyway, if the image doesn't change from field to field. This might be why you see stairs on rory's curb. It thinks the pixel shift of the CCD is motion and tries to compensate. Maybe some motion caps really are needed, it may make stills look worse but aide in motion.

[rory 0]

maybe its just my VIA chipset . ..

[Aardie 0]

Via aye Geovision Swear they dont work eh but they DO

 

P4 3 gig with Asrock KVM800 (Via Chipset) works a treat. with one Exception with HT On it Reboots willy nilly with it Off Rock Solid

 

I Still Prefer No Interlace the Captures just look Smoother will do a comparison this weekend on file size and fluidity and have some clips via ftp before the weekends out for comparison.

 

Regards

 

Keith

[rory 0]

cool thanks .. post the clips in the sticky if you like ..

 

Rory

[geo_dvr 0]

maybe its just my VIA chipset . ..

 

No its not the VIA chipset, i have an Intel chipset and i get similar poor pictures with De-Interlaced.

[rory 0]

i have another client though whos De is better, P4 intel etc ..

[geo_dvr 0]

 

Is it just me or doesn't every single image market "DeInterlaced" looks all interlaced to hell. I mean the curb at Rory's house looks like stairs! That hasn't been deinterlaced properly, then the supposedly interlaced images all look smooth. That curb isn't moving, no need for that.

 

Think this might be a labeling issue?

 

I was thinking that it may be a labelling mistake aswell. Isn't De-Interlaced images supposed to look better?

 

I have watched live video and still images on the de-interlaced resolution and the quality is very poor compared to the Interlaced.

 

Also when recording Audio you can only use the poorer De-Interlaced resolution, this may be a Geovision hardware limitation. This is the main reason i do not want to use the geovision card.