problem: my FS-4 recorded in fast motion (please read) at DVinfo.net

Nicholas Natteau · January 2nd, 2006, 11:05 AM

Hello everyone,

I own a Sony A1U HDV camera. Last week I just got my FS-4 with the HDV upgrade and recorded two clips with the camera in HDV 1080i mode.

The first clip recorded perfectly without any problems.

For reasons I cannot understand, the second clip was recorded by the FS-4 at high speed.

I was shooting cars driving down a freeway, and in the second clip the cars are recorded as though traveling at very high speed, like I was fast forwarding the scene as I was recording.

This problem did not appear on tape only in the FS-4.

Does anyone know what could be going on with the FS-4?

Why did it look as though I was fast forwarding the scene of cars moving.

Only two clips recorded, and already one malfunctioned with the FS-4. Scary.

Anxiously awaiting feedback.

- Nicholas

Dan Euritt · January 2nd, 2006, 11:53 AM

did you copy the clips to a computer, and see the fast playback issue when it played back on the computer?

Nicholas Natteau · January 2nd, 2006, 04:28 PM

Yes Dan,

Exactly. I copied the clips to my PowerMac G5 and saw this issue with one out of two clips.

- Nicholas

Dan Euritt · January 4th, 2006, 01:51 PM

now try playing the clip back directly from the fs-4, into a camera or deck via the fs-4 firewire connection... just to verify that it is indeed the clip that is wierd.

Daniel Kohl · January 5th, 2006, 04:29 PM

Is there any chance that you shot time-lapse on the second clip.

Just a thought.

Nicholas Natteau · January 5th, 2006, 05:43 PM

Hi Daniel,

No I don't believe so. As a matter of fact, correct me if I'm wrong, but I don't believe HDV can record time-lapse given it's MPEG-2 long-GOP structure can it?

I recorded in HDV mode not DV mode. While the footage looked fine on Mini-DV tape, the fast-forward problem occurred in the recorded file on the FS-4.

For a few seconds, the footage plays back at normal speed then speeds up dratstically as though I had somehow recorded in "fast forward".

I should mention that because FCP can't understand m2t files, I used MpegStreamClip to convert it into a Quicktime file. So I have no way of knowing whether this problem could have occurred within the m2t file. All I know is that I see it in the decoded Quicktime file after Mpeg Streamclip.

- Nicholas

Dan Euritt · January 5th, 2006, 09:32 PM

>>>So I have no way of knowing whether this problem could have occurred within the m2t file<<<

yes, you do... i just told you exactly how to do it.

Nicholas Natteau · January 16th, 2006, 09:57 PM

Dan thanks for your advice. Well it turns out that there were no problems in the native m2t files. But the problem happened on several Quicktime files after MpegStreamclip had finished translating the m2t files to Quicktime.

The m2t files are all fine. So is Mpegstreamclip the problem?
Looks like my m2t files get corrupted only after they get translated to Quicktime.

BTW, here is my problem QT file after being translated from m2t via MPEGstreamclip:

http://joric.com/freewayclip.mov

- Nicholas

Daniel Kohl · January 17th, 2006, 03:07 AM

Interesting effect. It sounds to me like Mpegstreamclip is doing something strange.

It looks similar to something I observed on an instructional DVD I was watching a while back. The off-text voice suddenly got high pitched and the video was noticeably faster, but I didn't notice what was happening right away. I just thought that there was a second off-text voice, since the video was clean.

I don't know if the two things are related, maybe its a mpeg coding glitch.

January 2nd, 2006, 11:05 AM	#1
Nicholas Natteau Regular Crew Join Date: Feb 2005 Location: Boston, MA Posts: 70	problem: my FS-4 recorded in fast motion (please read) Hello everyone, I own a Sony A1U HDV camera. Last week I just got my FS-4 with the HDV upgrade and recorded two clips with the camera in HDV 1080i mode. The first clip recorded perfectly without any problems. For reasons I cannot understand, the second clip was recorded by the FS-4 at high speed. I was shooting cars driving down a freeway, and in the second clip the cars are recorded as though traveling at very high speed, like I was fast forwarding the scene as I was recording. This problem did not appear on tape only in the FS-4. Does anyone know what could be going on with the FS-4? Why did it look as though I was fast forwarding the scene of cars moving. Only two clips recorded, and already one malfunctioned with the FS-4. Scary. Anxiously awaiting feedback. - Nicholas

January 5th, 2006, 04:29 PM	#5
Daniel Kohl Contributor Join Date: Dec 2001 Location: Frankfurt, Germany Posts: 571	Is there any chance that you shot time-lapse on the second clip. Just a thought. __________________ Daniel Kohl Frankenstein meets XL1

January 16th, 2006, 09:57 PM	#8
Nicholas Natteau Regular Crew Join Date: Feb 2005 Location: Boston, MA Posts: 70	Results...problem Not In M2t File!!! Dan thanks for your advice. Well it turns out that there were no problems in the native m2t files. But the problem happened on several Quicktime files after MpegStreamclip had finished translating the m2t files to Quicktime. The m2t files are all fine. So is Mpegstreamclip the problem? Looks like my m2t files get corrupted only after they get translated to Quicktime. BTW, here is my problem QT file after being translated from m2t via MPEGstreamclip: http://joric.com/freewayclip.mov - Nicholas Last edited by Nicholas Natteau; January 16th, 2006 at 11:01 PM.

January 17th, 2006, 03:07 AM	#9
Daniel Kohl Contributor Join Date: Dec 2001 Location: Frankfurt, Germany Posts: 571	Interesting effect. It sounds to me like Mpegstreamclip is doing something strange. It looks similar to something I observed on an instructional DVD I was watching a while back. The off-text voice suddenly got high pitched and the video was noticeably faster, but I didn't notice what was happening right away. I just thought that there was a second off-text voice, since the video was clean. I don't know if the two things are related, maybe its a mpeg coding glitch. __________________ Daniel Kohl Frankenstein meets XL1

January 2nd, 2006, 11:53 AM	#2
Dan Euritt Trustee Join Date: Mar 2004 Location: Carlsbad CA Posts: 1,132	did you copy the clips to a computer, and see the fast playback issue when it played back on the computer?

January 2nd, 2006, 04:28 PM	#3
Nicholas Natteau Regular Crew Join Date: Feb 2005 Location: Boston, MA Posts: 70	Yes Dan, Exactly. I copied the clips to my PowerMac G5 and saw this issue with one out of two clips. - Nicholas

January 4th, 2006, 01:51 PM	#4
Dan Euritt Trustee Join Date: Mar 2004 Location: Carlsbad CA Posts: 1,132	now try playing the clip back directly from the fs-4, into a camera or deck via the fs-4 firewire connection... just to verify that it is indeed the clip that is wierd.

January 5th, 2006, 05:43 PM	#6
Nicholas Natteau Regular Crew Join Date: Feb 2005 Location: Boston, MA Posts: 70	Hi Daniel, No I don't believe so. As a matter of fact, correct me if I'm wrong, but I don't believe HDV can record time-lapse given it's MPEG-2 long-GOP structure can it? I recorded in HDV mode not DV mode. While the footage looked fine on Mini-DV tape, the fast-forward problem occurred in the recorded file on the FS-4. For a few seconds, the footage plays back at normal speed then speeds up dratstically as though I had somehow recorded in "fast forward". I should mention that because FCP can't understand m2t files, I used MpegStreamClip to convert it into a Quicktime file. So I have no way of knowing whether this problem could have occurred within the m2t file. All I know is that I see it in the decoded Quicktime file after Mpeg Streamclip. - Nicholas

January 5th, 2006, 09:32 PM	#7
Dan Euritt Trustee Join Date: Mar 2004 Location: Carlsbad CA Posts: 1,132	>>>So I have no way of knowing whether this problem could have occurred within the m2t file<<< yes, you do... i just told you exactly how to do it.