Jittery playback - Never happened till now!

Liamo · Post by **Liamo** » Thu Aug 31, 2006 9:21 pm

First of all I have searched the forum and cannot seem to get an answer so apologies if I missed something. This is driving me mad and hasn’t happened up to now.I started 6 projects from friends tapes producing 6 discs and they all have jittery playback(and some pixelation)when played on player. It does not seem to happen when disc images are played on PC.DVD player is fine with other earlier discs. My work through was as follows:
1.Captured analog to avi from two different sources (VCR and camcorder) into VS9 on external HDrive.Added a few effects and encoded to mpeg. Resulting mpegs are as follows:
MPEG files
24 Bits, 720 x 576, 25 fps
Upper Field First
(DVD-PAL), 4:3
Video data rate: Variable (Max. 4000 kbps)
LPCM Audio, 48000 Hz, Stereo
2.Brought them into DVDWS2 did some limited cuts on some projects, none on others. Convert to disc template unchecked and files compliant.Burnt disc image to drive as follows: MPEG files
24 Bits, 720 x 576, 25 fps
(DVD-PAL), 4:3
Video data rate: Variable (Max. 7000 kbps)
LPCM Audio, 48 KHz, Stereo
3.Burnt images on discs using imgburn at 4x.
I burnt previous images I had done just in case it was my burner but they were fine.I cannot think what I might have done differently.I worked back through the mpegs to check the field order(I used gspot software to check them)and the avi’s before that even through it doesn’t show field order on avi’s.Everything is set up for PAL.I’m just stumped.I tried from avi’s doing a test and again jittery at playback. Any suggestions gratefully appreciated.Thanks!

sjj1805 · Post by **sjj1805** » Thu Aug 31, 2006 11:21 pm

I think your workflow is:

VHS ==> Camcorder ==> Hard drive.

If so you appear to be using what we term "Pass Through" and I suspect your camcorder is connected to the computer with a firewire cable. If my interpretation is correct then you have the wrong field order and should be using lower field first.

Another observation is that you are capturing to an external hard drive.
Although some users have reported that they do this successfully, I have found that an external hard drive is unreliable for video capture due to the high volume of data being passed to the hard drive. Try capturing to an internal hard drive instead.

Liamo · Post by **Liamo** » Fri Sep 01, 2006 10:24 am

Thanks Steve for the reply.
I was capturing as follows
Analog Camera/VCR -->via Canopus ADVC55--> PC firewire -->external drive.

After working back the only thing left to check was an issue with the original captured files(I was hoping it wouldn't be!).I honestly cannot remember whether I captured using UFF or LFF.Does this matter in a captured avi?And do you know if there is any way of checking the files if I made a field order mistake at capture?If so there any way of changing this rather than recapturing?

I have found some problems capturing to the external hard drive.But these were always just dropped frames if I hadn't defragged.
Sorry for all the questions and thanks again.
Liam

Liamo · Post by **Liamo** » Fri Sep 01, 2006 10:29 am

Just another thing.Because of dropped frames I captured some files to PC hard drive.The projects resulting from these came out the same.
Liam

GeorgeW · Post by **GeorgeW** » Fri Sep 01, 2006 11:12 am

Did you capture to DV .avi, or some other type of .avi

What I would do is take a small section of one of the .avi files that you know has the problem, and create a small test project. Just change the mpeg encoding to Lower Field First, and burn it to RW disc to see how it plays on your set-top dvd player. If it looks good, then you know you just have to change the field order during the mpeg encoding step.

Regards,
George

Devil · Post by **Devil** » Fri Sep 01, 2006 1:29 pm

As a guess, I would suspect that your problem MAY lie in your using an external drive. If USB2, this is dicy, especially if you have USB mouse, keyboard, or anything else working, as these must be constantly interrogated, consuming bandwidth. If IEEE-1394, then capturing and simultaneously sending the signal through the same hardware may be dicy, especially if the HDD needs defragging.

That is where I would startd looking.

Liamo · Post by **Liamo** » Fri Sep 01, 2006 1:58 pm

Thanks George and Devil.I captured to DV .avi.
I will try with lower field first tonight.It is an analog source but maybe wrong setting at capture.It must be something at capture.Annoying that I have always done it this way and haven't had this before.

My External drive is also firewire(along with my analog capture device).I'll do a small capture to both drives once they are defragged and see the result.

Devil · Post by **Devil** » Fri Sep 01, 2006 3:55 pm

It would seem that you are capturing and saving using the same IEEE-1394 interface, as I suggested earlier.

Try a capture to an internal defragged disk (SATA or ATA IDE).

Liamo · Post by **Liamo** » Mon Sep 04, 2006 9:38 am

Just for anyone else.
I think I solved the pixilation problem. Bad discs from a reputable disc manufacture. Pixilation problems seem to occur on the burn end.
The picture was still jittery. I captured to internal drive but it still made no difference. I then did as George said and rendered out mpeg as lower field first and this seems to have solved it so I guessed I had made a mistake in the settings at the capture end. Funny thing is I went back to capture 2 avi’s that I hadn’t kept and had to redo. Checked capture settings and project properties to make sure they were upper field first (for analog).Made mpeg with Upper Field First and jittery picture again on TV after burn. Made file in LFF and it was fine. I don't understand it but anyway jittery picture problems seem to be caused (in my case anyway) by field order issues.
Thanks George Devil & Steve for suggestions for avoiding future problems.

skier-hughes · Post by **skier-hughes** » Mon Sep 04, 2006 8:24 pm

The canopus product does the analogue to digital conversion, you are not capturing an analogue signal.

Liamo · Post by **Liamo** » Tue Sep 05, 2006 10:42 am

Of course..daft of me

its a converter!I just always assumed as in the recommended procedures that if the recording device was analog that you should use upper field first all the way through.This pretty much means that all my work will be in LFF from now on.Thanks Graham.