Canon DV Input - Scene Detect - 2 frames early

[Bismark]

I just used PE4 to input some tapes from my Canon HV20. It divided the scenes by correctly by time code, but put the last two frames from the previous scene into each next clip. Specifically, each clip has the last two frames from the previous scene. This means it is starting the clip two frames too soon.

What am I doing wrong? I set PE4 to do scene detect by time code. For now, I just review the clip and reset the IN pointer.

Thanks for any ideas.

[Chuck Engels]

You are not doing anything wrong, I have the same problem
It is a bug in the program.

[JohnnyO]

I have a Sony miniDV camcorder. I don't see this problem at all. Is this really a bug in Premiere Elements, or is it a problem withthe Canon?

Can you capture with another program to verify?

[Chuck Engels]

I should clarify,
This is a problem when capturing from a HDV camcorder, I think primarily when you down convert in the camera on capture.
I do not have this problem capturing from an SD MiniDV camcorder. It has happened with two different models of Canon, one the HV20 and the other is the XH A1.

[Bismark]

Thanks for the reply. For once it wasn't my fault.

[Blueshoe]

Hi there,

I experienced the same problem and asked for help in the hv20.com-forum. Someone sent me the link to Your post.

I tried the scenedetection on Studio11, Moviemaker and AVCutty on two PCs- same result.
It really seems that the downconversion from HDV to DV takes 2 frames an the datecode isn't corrected to this latency.

Do you have a solution for this problem?
This makes any scenedetection useless if the datecode is used.
I mailed Canon about this bug. Hopefully they have a solution!

[Chuck Engels]

I have the same problem and have learned to live with it. I work with about 4 hours of tape every week and have the same problem.
I have to cut the first frames from any footage I keep, it really hasn't been too bad and it is still better than working with one long clip.
If I capture HDV to an HDV project I don't have this problem, if I capture SD to an SD project I don't have this problem, only when downconverting HDV to SD in the camera and capturing into a SD project.

This sounds like something RJ could figure out, now if someone would just give him a Canon HV20...

[Ken Jarstad]

Despite the inconvenience, the two frame delay seems appropriate to me. It has to take SOME amount of time to process 4:2:0 1440x1080 MPEG video to 4:1:1 720x480 DV-AVI video.

And, although I have no way to prove it, the resampling of the chroma seems to be done in such a way as to keep far more color information than theory would allow. Perhaps having four times more color info in the larger frame size allows them, through clever programming, to transfer more color information to the smaller frames.

[Blueshoe]

Despite the inconvenience, the two frame delay seems appropriate to me. It has to take SOME amount of time to process 4:2:0 1440x1080 MPEG video to 4:1:1 720x480 DV-AVI video.

Full ACK, but delaying the corresponding datecode accordingly can't be such a big hack?!

[Ken Jarstad]

Ah, yes, I see what you mean. That does seem to be an 'oops' that could be easily fixed in the codec processing. And, according to Chuck, the Canon XH A1 has the same problem.

So, is this a Canon problem, or do any other HDV brands commit the same error? And, does the latest generation of Canon have it fixed - HV30 and so on? I sure wish those programmer folks were as meticulous and perfect as I am! No, wait. I wouldn't want products that bad

[Chuck Engels]

I have only used the two Canon models for HDV, don't know if it is all HDV downconverted in any camera or not.
It would be great to know if this is strictly Canon cameras or if it is related to the HDV technology in general.

[Blueshoe]

I would be happy if someone could check this issue with a non Canon Camera.

Canon wrote me, that it is a problem with the GOP-structure of the HDV-MPEG2-Stream, that isn't fixable. I can't beleive that because it's a constant delay of 2 frames...

[Jan Laros]

I did a test with the Sony HDR-HC1. The recording was done in HDV 1080i. I switched the ILink conversion in the camera ON and captutured with PE4 in a DV-Standard project with the scenedetection on timecode. I do not get the effect that the last two frames of the previous clip are visible in the next clip. Clips are in perfect order.

When I capture the same material in HDV using HDV-Split each clip is 2 frames short at the beginning of the clip. Makes you wonder what is happening.

[Ken Jarstad]

Ah-hah!