OK, once again

1. Imagine you have typical project with field order - bottom field first
2. Insert DV clip with field order - bottom field first
3. Insert Velicoty envelope to this clip and set it to -100%, so it will play backwards at the same speed
4. Render the clip to MPEG-2 in DVD format and burn it to DVD

Now imagine the original video has fields ABCDEFGH....
The resulted video in DVD format has fields ....GHEFCDAB
But it should be ....HGFEDCBA

... so the two fileds from one frame are reversed and the video will play jerky
The field order must be reversed on negative velocity envelope values to play smooth

I believe Vegas automatically reverses the field order when using negative velocities. So, you should be getting HGFEDCBA.

Unfortunately, this bug ist well-known, and has been explored some time on www.vegasvideo.de/forum.

True, the field order must be reversed, when you go to a negative velocity. The best way to do so is to render the event to a new track, with an reversed field order uff; import this event again, correct the field order back to bff (for DV-avi), and apply now the velocity envelope with -100%.

Important: make sure that "blend" is activated in the project properties.

Comment: that has been tested with DV-PAL-avi videos.

Kr
Wolfgang

By odd coincidence, I happened to need to reverse some video today. I remembered that the last time I did it, I didn't like the results, so I searched the forum today, and found this current message.

Based on the input in this thread, I did some tests and confirmed that the Vegas 4.0d velocity envelopes definitely have a nasty field reversal bug.

Note: This bug, as the original poster noted, makes the velocity envelopes totally useless anytime you need to go between forward motion and reverse motion during the same event. If you only need reverse motion, then you can reverse the event fields and get a good render.

Here are the tests I performed.

I took some video that included a left/right pan and applied a -100% velocity envelope. I then rendered this video and previewed it on an NTSC monitor.

It looked horrible.

The fields were obviously reversed. I tried another render with Force Resample. No improvement.

I tried another render, and reversed the fields using the Custom button in the render dialog. No improvement.

I then clicked on the event, and reversed the fields there (i.e., I changed from "Lower Field First" to "Upper Field First." The video rendered correctly.

I also tried applying Supersampling of 2 to the unmodified event and was able to get pretty good quality. This may be the workaround for those that need to go forwards and backwards in the same event.

Sony, please put this on your list of things that need to be fixed in the next release.

John,

the solution has been posted two messages earlier - it is necessary to render the event with reversed field order to a new track; and then apply the velocity envelope with -x%. Then it works fine - but only if you have either "blend" or "interpolate" in the project properties activated.

Took us a while to figure that out in the German vegas-forum, especially that "blend"/"interpolate" is important here.
:-))

the solution has been posted two messages earlier - it is necessary to render the event with reversed field order to a new track; and then apply the velocity envelope with -x%. Then it works fine - but only if you have either "blend" or "interpolate" in the project properties activated

My "solution" was a little different: I simply reversed the field in the event, rather than in the render. That seemed to do the trick.

I think we tried to reverse the fieldorder too without prior rendering to a new file too, John. But as far as I remember it did not work - but I am not sure here. Will try it again...

****** John said:
I also tried applying Supersampling of 2 to the unmodified event and was able to get pretty good quality. This may be the workaround for those that need to go forwards and backwards in the same event.
******

Did you really use the same event, based on the same file on the harddisk? Only reversed the fieldorder and both directions worked within one event after going to UFF, without any errors? Or have you splitted the event in two events at the point where you changed the direction?

Did you really use the same event, based on the same file on the harddisk? Only reversed the fieldorder and both directions worked within one event after going to UFF, without any errors? Or have you splitted the event in two events at the point where you changed the direction?

I used one NTSC event, and did not reverse the event field order. I then applied a velocity envelope and added points that were both positive and negative (i.e., both forward and reverse motion). I then turned on the video bus and inserted supersampling and set it to 2. The result looked reasonably good. It certainly did not have the "jitter" that you get when the fields are reversed and the the camera pans side-to-side.