HaroldB Posted October 27, 2011 Report Posted October 27, 2011 What is "offset" in the property tab of a video clip used for?What it seems to do is hold the first frame of the video in a freeze frame for the specified interval. Is that its purpose, or am I missing some clever PTE feature?H Quote
Lin Evans Posted October 27, 2011 Report Posted October 27, 2011 Hi Harold,Offset, whether in the Audio or Video functions tells the software "when, in respect to the start of the timeline for this video or audio" you wish to have that object "start." Let me first explain it with sound because it's easier to understand that way.Let's say you had a music background and you wanted the music to start after an image slide had been on the screen for six seconds. You would set the offset to six seconds and after your image was displayed for six seconds the music would begin. In contrast, the "start time" is how far "into" the music track, you want the sound to begin. Let's say you wanted to skip the first 12 seconds of the sound track and begin the playback at exactly the 12 second time into the music. You would then set the "start time" to 12 seconds. So if you wanted to have that music begin playing at six seconds into your image, you would sett the offset to six seconds and the "start" time to 12 seconds.Video is exactly the same way. "except" that the first frame of the video, as you noted, would "freeze" until the offset time rolled around and then the video would begin. To avoid seeing the first frame, simply keyframe the opacity for the video to zero using two keyframes. The first will be set to zero opacity and the second to zero to hold this zero opacity along the timeline with the third to 100% at the precise time you want the video to "appear." The timing between keyframe two and three will determine how quickly the first frame fades in.Best regards,Lin Quote
HaroldB Posted October 28, 2011 Author Report Posted October 28, 2011 Video is exactly the same way. "except" that the first frame of the video, as you noted, would "freeze" until the offset time rolled around and then the video would begin. To avoid seeing the first frame, simply keyframe the opacity for the video to zero using two keyframes. The first will be set to zero opacity and the second to zero to hold this zero opacity along the timeline with the third to 100% at the precise time you want the video to "appear." The timing between keyframe two and three will determine how quickly the first frame fades in.Hi, Lin!Wouldn't I get the same effect by simply having the video object appear where I would put the third keyframe in your example above?It seems to me that the only thing the offset field is buying me is the ability to see the first frame in freeze-frame for a user-specified time. Am I still missing something?H Quote
Lin Evans Posted October 28, 2011 Report Posted October 28, 2011 Hi Harold,It seems to me that the only thing the offset field is buying me is the ability to see the first frame in freeze-frame for a user-specified time. Am I still missing something?Yes, I think so....It seems that you may have a misconception about how keyframing works with PTE...Keep in mind that you can use a video as a background to run behind a series of sequential still slides and you can have a series of still slides running sequentially behind a video. In the case of a single slide as in the example, how would you tell the video to begin say six seconds into the slide while the still slide is still visible without the offset? You could "duplicate" the slide and start the duplicate at the six second mark concurrent and as a second object on a layer with the video residing on a different layer, but without the offset there is no way to make this happen using a single slide and video. When you put two or more objects in the same slide frame on a timeline, they will all be visible simultaneously. That is setting the first keyframe at a starting point somewhere along the timeline other than the beginning will not cause the object associated with that keyframe to "wait" and appear at the time where you have moved the first keyframe position. So to make the video "appear" at the position of the third keyframe, you could set the opacity to zero at the first keyframe then another at zero and cause the video to "appear" at keyframe three but it would have already been running for the time frame between keyframe one and keyframe three. You would miss the first part of it that way. The only way to actually have it "start" at the time of keyframe three would be to have it as a second object or "slide" and to keep the image behind it you would have to duplicate it as mentioned above.The reason I mentioned a possible misconception about how keyframing works is that there really is no straight-forward way to have the video "start" at the position of the third keyframe without the offset. As I said, you could do a "work-around" by duplicating the slide, but there are many scenarios where you can't do a work-around but need to control "when" your video begins playing.A scenario of the type above might be that you have two or more videos running simultaneously on your slide (slide is being used as a generic term here for background and timeframe) and you want to control the timing for when each begins playing. You can't do that with keyframes. Once you work with videos in PTE for a while, the reason for the offset will become more apparent.Best regards,Lin Quote
HaroldB Posted October 28, 2011 Author Report Posted October 28, 2011 When you put two or more objects in the same slide frame on a timeline, they will all be visible simultaneously. That is setting the first keyframe at a starting point somewhere along the timeline other than the beginning will not cause the object associated with that keyframe to "wait" and appear at the time where you have moved the first keyframe position. . . . The reason I mentioned a possible misconception about how keyframing works is that there really is no straight-forward way to have the video "start" at the position of the third keyframe without the offset. As I said, you could do a "work-around" by duplicating the slide, but there are many scenarios where you can't do a work-around but need to control "when" your video begins playing.<nods> I didn't think I could do this with keyframes. But I would have thought that I could do exactly this by using the Time Range parameter on the Common tab!I tried it, and you are most certainly right. Even if I use Time Range to get the video object to appear somewhere in the middle of the "slide time", it is as if the video has been running since the beginning of the "slide time" unless you specify offset. This does not seem intuitive to me, but I guess I get to live with it.BTW, Igor, there seems to be a bug in PTE. When I do this setup (having a second video come in later in the "slide time" and be reduced in size, it jerks when coming in instead of just appearing. It's as if it "came in" in the wrong place on the screen and then was put into the "right place".H Quote
davegee Posted October 28, 2011 Report Posted October 28, 2011 Harold,Re: Your "possible" bug.Consider this:When you drag a video into the Slide or Timeline view (I'm assuming "Keep Full Slide Duration" is ticked?) the slide duration is automatically set to the length of the video and an overlap with the previous and next slide is automatically set up.If you make any changes to the video with the "trimming" utility the changes made will make the Slide Duration no longer equal to the Video Duration.You now have to manually transfer the "new" Video Duration time to the Slide Duration to restore the correct relationship between your video and its previous and next slides.Altering the OFFSET further complicates the issue.I would suggest that a possible use for the "offset" would be when you have two videos in the same slide when the full slide duration time would equal the sum of the two individual slides. The second video would be offset to the first and an overlap between videos (by means of keyframes) would occur within a slide as opposed to the beginning and end.I asked Igor to consider a button to set the Video Duration equal to the Slide Duration (after adjustment) but I fear that it got lost in the furore over "Keep Full Slide Duration".DG Quote
Ken Cox Posted October 28, 2011 Report Posted October 28, 2011 your topic says" VIDEO CLIP"THEREFORE it belongs under the video section ken Quote
fh1805 Posted October 28, 2011 Report Posted October 28, 2011 Ken,I'm sorry, buddy, but I have to disagree with you. The forum section is headed "Video Output", Harold's post was about using video as input.regards,PeterP.S. The Video Output section doesn't have a pinned entry "Purpose of this section". That surprises me as, at one point in the past, I worked through all the sections and added such a topic where there wasn't one already. Quote
HaroldB Posted October 28, 2011 Author Report Posted October 28, 2011 your topic says" VIDEO CLIP"THEREFORE it belongs under the video section kenHi, Ken!<laughs> But it doesn't have to do with video OUTPUT per se! Starting with PTE 7, PTE also takes video as INPUT!<laughs> It's OK wherever it is, Ken, as long as Igor sees it.H Quote
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