Jerky movement on reversed clip

[jparnold]

Part of a recent DVD movie I created contains a clip which I applied REVERSE (motion) to and when I view the movie using my standard DVD player and plasma TV this clip is very jumpy (kerky movement). All the other clips in the movie (not reversed) are NOT jumpy.
Is there a secret to the use of REVERSE (clip) or is this normal especially when the scene was recorded at standard 1/50th second shutter speed?
I am using Mediastudio version 7 and then authored using VideoStudio.
Thanks
John

[Devil]

Before applying Reverse, change that clip to Frame based.

If I were you, I'd start a new project with just the clip, using Frame based as the default (as opposed to Field order upper or lower first). Apply the reverse and Create an AVI of the project, then import that file in the full project. When you render or encode, it will then pick up your settings.

You see, if you have a given field first, when you reverse it, that same field becomes second and the quality deteriorates, especially if there is movement.

[Gorf]

Brian, If that's the cause of the problem, MSP has taken a severe backward step at some point since version 6. I've reversed clips without interlacing problems, and it seems common sense to me that if you're going to be playing the last frame of a clip first, then you'd write the software so that you play the second field of each frame first.

John - I think your problem is that the project settings have the wrong field order set, and these incorrect settings are being "inherited" the clips.

Under normal circumstances there is no nett effect - the render engine does not change the field order because the clip agrees with the project (in other words, it's not having to do any work, so it's ignoring the incorrect field order). When you reverse a clip, the render engine is reversing the frames as it should, but where it thinks it is using the second field, it is actually using the first (because it doesn't know any better).

A quick fix is to copy the video file that is the basis for the reversed clip to a new name ("Copy of Source.avi" for example). Then use "replace video file" for the reversed clip and set it to this copied file. Then, for the clip, switch its field order (for example, if it's lower field first, change it to upper).

The reason you're copying it is because for all versions before v8, MSP applied media source options to all clips that used the same media file. you don't want this to happen unless all your clips are from the same source video file. I've not played with MSP8 enough to see if that does it too, but it's a moot point as I don't know what version you're running anyway.

This is a "quick fix" because there are other potential problems. If you use any feature that causes the render engine to do any work (such as a video filter, transition, moving path etc) it will do this work on the wrong field first.

The proper fix is to set the correct field order then go through the project changing it for the clips, but that might be time consuming if you've finished your edit.

[jparnold]

Thanks Gorf,
I sort of understand what you mean but not entirely.
My video file is made up of many clips and is around 45 minutes in length. The clip I want reversed is around 10 seconds. If I create a video file of the just clip I want reversed which has field order A and is reversed how do I insert that into the whole movie? I don't understand use "replace video file"
I think I understand what causes the problem but cannot your description of the quick fix.
Do I understand correctly that you can't fix the problem by creating a separate file (clip) which is reversed and field order A and then inserting it into the timeline of my full movie.
I understand the problem but not the quick fix method.
Thanks
John

[jparnold]

Gorf,
Sorry but I think I have worked out what you told me for the quick fix.
What I did was to create a separate file of just the scene I want reversed and saved it (lower field first).
I then created a new project, pulled the separate file (scene) I created above onto the time line, set the clip to REVERSE and with field order upper field first, then selected REPLACE WITH and selected the original (unreversed) avi file and then saved as a new (reversed) file (clip) to be added later to the entire movie I am creating.
Have I understood and done it correctly?
John
BTW I have version 7 of MediaStudio.

[Gorf]

Hi, John.

I’m not sure if you’ve done it correctly, because it’s not exactly clear which (incorrect) field order is there to start with.

It would be far better to tell us what the field order for the project and the clip itself is, and amend the entire project so that the right settings are used.

The quick fix was really dependent on how urgently you need this finished, and how extensive the project is. It’s really just a botch job.

Now I know you’re on MSP7, I can tell you the sequence:

• Right click the clip and select “Properties...” to identify the source video file for the clip you want to reverse, e.g. D:\Tape01.avi
  Navigate to that file in Windows Explorer, select it, then press {Ctrl-C} and {Ctrl-V} to make a copy.
  Switch back to your project in MSP. Close the properties dialog if you haven’t already.
  Right-click the clip and select “Replace With” then select “Video file”.
  Navigate the dialog to D:\Copy of Tape01.avi (or whatever your copy ended up being called) and click “OK”
  Right-click the clip and select “Media source options...” and note the field order in the first combo box. Whatever field order it is, set it to the other one.

This clip should already be reversed, because you've replaced the original source with a new one. All other attributes remain.

I know you're (potentially) going to end up using gigabytes of extra storage for the copy source, and the reversed clip might only be a few seconds, but this method will work irrespective of your field order or where it's wrong.

[jparnold]

Thanks Gorf,

Sorry for the lemngth of this reply and please ensure you read the last paragraph - maybe read that first just in case.

I am not sure if I can try that with my current set up as my hard drives are formatted FAT32 not NTFS and the total movie being around 45 minutes would be around 10Gb too big for FAT32 plus I currently don't have that much spare space on my drives as they currently contain around 3 hours of unedited 'master' video files (I only ever output my 'movies' to MPEG2 - DVD format).
UNLESS of course if can do what you suggest using MPEG2 files - what do you think? (I must upgrade to much larger hard disks - I currently have around 60Gb total disk size).
If this is not possible then I will probably choose to leave these reversed scenes out.

I usually have preferences set to 'lower field first' (in answer to your question).

Did you say that later versions of MSP would not have this problem?

In the future when I am 'shooting' video and either pan a scene or the scene is of movement away from the camera I will also 'shoot' the same scene in reverse (either pan back or 'shoot' the scene with the movement coming back if that is possible. I then won't have to use 'reverse'.

To quickly explain why I applied reverse - we went on a funicular railway and I only took 'shots' on the way up. To make the movie appear better I thought I should include 'shots' on the way back which I didn't have so selected unused shots going up and (tried to) reversed them. I should have taken some scenes on the way back down although if reverse worked properly .......
I guess we all learn to do things better with experience.

BY THE WAY I should have pointed out that I also have VIDEOSTUDIO ( version 8 ) which I MAINLY use to do my editing as I find it easier to cut scenes from the main unedited movie (which I capture in 10 minute (length) files from tape and then 'cut it up and rearrange clips' - please don't ask why).
I used MSP to simply REVERSE one clip which I saved as type AVI and then inserted this (AVI) file into the timeline within the VIDEOSTUDEO project. Maybe I should have mentioned this before but I didn't think it was relevant to the problem.
Do you think the problem could be solved in a different manner now (please don't swear)?


John