Dropframes at DVinfo.net

Brian Duke · January 15th, 2006, 06:26 PM

Hi,

How do I check if I got any drop frames after I transferred to FCP? Maybe its a stupid question, but I might be getting dropframes without knowing it.

Panos Bournias · January 15th, 2006, 08:30 PM

Hi Duke. As I had the same problem using an Avid, the drop frames are not visible on the LCDs.
What I do is: I preview the capture on an HD monitor and I preview the m2t file on the same monitor while exporting to tape.
Avid has also a usefull command in its console.
The command is: " repairallsequences". With this command even if the footage cannot be repaired you can get a list of the corrupted clips.
Try to see if final cut pro has such a function.
The other solution is to purchase a black magic card and preview directly your footage while editing. People say that you can do so.
Panos B

Stephen L. Noe · January 15th, 2006, 08:37 PM

Is there a setting in the FCP contol panel that you can instruce the program to log all dropped frames or "stop digitizing" if it encounters a dropped frame. This is the way Liquid works. It will create a list of dropped frames either on import or gives you the selection on what action to take in case of a dropped frame in logging.

Maybe FCP has this type of reporting and control?

Brian Duke · January 15th, 2006, 09:07 PM

Stephen, I think it does, but the problem is that FCP does not support the JVC HD100U 24p yet, so I don't digitize directly with FCP, but instead use HDVXDV which I do not believe detects it. I know there is some other way to check it out, but I haven't been able to figure it out yet. I was hoping some of you professionals would know.

Panos,

So Avid repairs drop frame clips? What happens with drop frame clips? How can you transfer dropframes to film, if needed?

Panos Bournias · January 16th, 2006, 12:14 PM

The Avid people claim that it can repair drop frames, or corrupted media that are repairable. In my case a clip with drop frames was repaired.
The Avid people say that: even if the application cannot repair the clips you get a list of the corrupted media so you can redigitize them.
It is a good function that not many people know as the console commands remains a mystery. The tip was given to me by Avid as I had problem with the drops. I asked for a list of commands that could be usefull but they told me that it is not available.

Tim Dashwood · January 16th, 2006, 12:35 PM

Duke,

HDVxDV shouldn't drop frames even on a lower end system digitizing to firewire hard drives. Just make sure it is the only app running at the time. If you can digitize DV without dropping frames, then your system is fine for capture the m2t stream (which is a lower bitrate than DV.)

On the flip side, you need some real processing power to playback an m2t stream at 720P. Decoding and playing back is much much harder than simply capturing the stream.
You may be dropping frames during playback, but this doesn't mean that the original is missing any frames.

As for double-checking, just go through frame by frame in a suspected problem area to confirm that all the frames are there. The "mark long frames" might work in FCP, but I've never tried it.

Brian Duke · January 16th, 2006, 01:25 PM

Tim,

When I played back a clip I saw it went from 24p to sometimes for a split second showing 23.98/97 etc. So there may be something missing. How do i fix that in case I have to transfer to film? Im worried I may be getting dropped frames when I original record footage on my JVC.

Duke

Tim Dashwood · January 17th, 2006, 12:24 PM

Quote:

Originally Posted by Brian Duke

Tim,

When I played back a clip I saw it went from 24p to sometimes for a split second showing 23.98/97 etc. So there may be something missing. How do i fix that in case I have to transfer to film? Im worried I may be getting dropped frames when I original record footage on my JVC.

Duke

You mean in Quicktime player with the "Movie Info" window showing the playing frame rate? That is pretty normal for Quicktime player because, on your computer screen, the monitor refresh rate is "true" so the playback frame rate may fluctuate in order to accomodate a 23.98 frame rate. If the file itself is not missing any frames, then you will not have any problems going to film. The same goes for outputting to tape.

Brian Duke · January 17th, 2006, 05:59 PM

Thanks. I hope that is all it is =)

January 15th, 2006, 06:26 PM	#1
Brian Duke Major Player Join Date: Oct 2005 Location: Hollywood, California Posts: 899	Dropframes Hi, How do I check if I got any drop frames after I transferred to FCP? Maybe its a stupid question, but I might be getting dropframes without knowing it.

January 15th, 2006, 08:30 PM	#2
Panos Bournias Regular Crew Join Date: Sep 2005 Posts: 109	drop frames Hi Duke. As I had the same problem using an Avid, the drop frames are not visible on the LCDs. What I do is: I preview the capture on an HD monitor and I preview the m2t file on the same monitor while exporting to tape. Avid has also a usefull command in its console. The command is: " repairallsequences". With this command even if the footage cannot be repaired you can get a list of the corrupted clips. Try to see if final cut pro has such a function. The other solution is to purchase a black magic card and preview directly your footage while editing. People say that you can do so. Panos B

January 16th, 2006, 12:14 PM	#5
Panos Bournias Regular Crew Join Date: Sep 2005 Posts: 109	Avid console The Avid people claim that it can repair drop frames, or corrupted media that are repairable. In my case a clip with drop frames was repaired. The Avid people say that: even if the application cannot repair the clips you get a list of the corrupted media so you can redigitize them. It is a good function that not many people know as the console commands remains a mystery. The tip was given to me by Avid as I had problem with the drops. I asked for a list of commands that could be usefull but they told me that it is not available.

January 16th, 2006, 12:35 PM	#6
Tim Dashwood Wrangler Join Date: Aug 2005 Location: Toronto, ON, Canada Posts: 3,637	Duke, HDVxDV shouldn't drop frames even on a lower end system digitizing to firewire hard drives. Just make sure it is the only app running at the time. If you can digitize DV without dropping frames, then your system is fine for capture the m2t stream (which is a lower bitrate than DV.) On the flip side, you need some real processing power to playback an m2t stream at 720P. Decoding and playing back is much much harder than simply capturing the stream. You may be dropping frames during playback, but this doesn't mean that the original is missing any frames. As for double-checking, just go through frame by frame in a suspected problem area to confirm that all the frames are there. The "mark long frames" might work in FCP, but I've never tried it. __________________ Tim Dashwood

January 17th, 2006, 05:59 PM	#9
Brian Duke Major Player Join Date: Oct 2005 Location: Hollywood, California Posts: 899	Thanks. I hope that is all it is =) __________________ Visit me and my work at www.artofduke.com

January 15th, 2006, 08:37 PM	#3
Stephen L. Noe Trustee Join Date: Apr 2005 Location: Chicago Posts: 1,214	Is there a setting in the FCP contol panel that you can instruce the program to log all dropped frames or "stop digitizing" if it encounters a dropped frame. This is the way Liquid works. It will create a list of dropped frames either on import or gives you the selection on what action to take in case of a dropped frame in logging. Maybe FCP has this type of reporting and control?

January 15th, 2006, 09:07 PM	#4
Brian Duke Major Player Join Date: Oct 2005 Location: Hollywood, California Posts: 899	Stephen, I think it does, but the problem is that FCP does not support the JVC HD100U 24p yet, so I don't digitize directly with FCP, but instead use HDVXDV which I do not believe detects it. I know there is some other way to check it out, but I haven't been able to figure it out yet. I was hoping some of you professionals would know. Panos, So Avid repairs drop frame clips? What happens with drop frame clips? How can you transfer dropframes to film, if needed?

January 16th, 2006, 01:25 PM	#7
Brian Duke Major Player Join Date: Oct 2005 Location: Hollywood, California Posts: 899	Tim, When I played back a clip I saw it went from 24p to sometimes for a split second showing 23.98/97 etc. So there may be something missing. How do i fix that in case I have to transfer to film? Im worried I may be getting dropped frames when I original record footage on my JVC. Duke