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defender

Preview going black?

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Hi all,

 

I love using Videopad, but the one problem that's bugging me is that from time to time a video in my sequence will just display blackness in the preview. The audio continues to run when playing the preview. At first I noticed it on the version on my laptop (3.04), but I just downloaded 3.24 on my (much more powerful) desktop and just had the same problem occur. On 3.04, I would notice this happening to an entire segment, but on 3.24 it's happened in the middle of a segment.

 

Anyone have any experience troubleshooting this?

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I figured it out. Not only does the preview go black, but the export ends up black as well.

 

But here's why. I have that section of video running at clip speed 75%. For that segment of video (let's say it's 2 minutes long), the first 75% (1 minute 30 seconds) plays fine. Exactly at 1:30, the video goes black until the next video segment starts. The audio from that video (which is also slowed to 75%) plays as expected.

 

I thought I could remedy the situation by cutting the video at the 75% point, which does indeed bring the picture back at 1:30, but now there's two segments, both running at 75%. The first segment now has video from 0:00 - 1:07 (75% of 1 minute 30 seconds) and the blackness from 1:07-1:30. The Second segment has a similar situation... the first 22 seconds have video and the last 8 are black. So combined together, the original 2 minute segment that went black at 1:30 now has video from 0:00-1:07, video from 1:30-1:52, and blackness everywhere else. I'm just moving the black around.

 

So there's your bug report, and should be reproducible. I'm using 3.24, unlicensed.

 

My only solution now is to not play the video sped up.

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Hi

 

THIS IS A BUG or a bad implementation of the feature as it stands.......

 

 

e.g. Two clips on the time line. Clip 1 followed by clip 2

All thumbnails present etc. and ready to go...

 

Right click on first clip and select "Change Clip Speed" and set at 75%

Timeline builds apparently OK and clip 1 butts up to clip 2. However, the clip preview (left pane) shows the OUT marker at 75% of the clip with the 25% to the right of it as greyed out.

 

Playing the timeline shows a break at 75% and black frames until clip 2 comes in. There is also a chequered (blank) thumbnail present in this section under the sequence preview pane.

 

Clip 1 in fact is apparently chopped off at 75%. (or at any value you set for the speed change.) although apparently on the timeline this is not so.

 

I think this is the reason...

 

If the two clips are on the same videotrack and consequently butt up and you choose to slow down clip 1 , it will in effect become longer. However as there is insufficient space to accomodate the lengthened clip 1 and as clip 1 does NOT push clip 2 along the time line as it logically should it will consequently appear to fill in the space it has but truncate the extended section as evidenced by the OUT flag in the preview pane and the chequered frame shown in the sequence thumbnails. Playing the sequence however shows that there is also an error in how the data is interpreted by VP as it thinks the "chopped off" bit is still there but has nothing to play

It seems that VP fails to copy the required frames to slow down the clip, or if it does there is a bug that prevents them from playing. It should push clip 2 to the right to get the lengthened clip 1 in.

 

There is a workaround...

 

If you place clip 1 onto an EMPTY upper overlay track and clip 2 onto the sequence line so it follows clip 1 and then slow down clip 1, it will expand along the overlay track correctly. However there is another bug here as the expanded section of clip 1, which should be an overlay, will NOT play over clip 2 as it should.

(Probably no big deal as In any case you would need to move clip2 along so it follows clip 1.)

 

It shows the difficulty of programming this effect when there are multiple tracks to deal with. It needs thinking out again and re-implementing.

 

Changing the speed to 200% (over 100% to speed up clip) shortens the clip as expected but leaves a space. It doesn't move clip2 back to fill this space. But you can easily close the gap.

 

Nat

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THIS IS A BUG or a bad implementation of the feature as it stands.......

 

 

e.g. Two clips on the time line. Clip 1 followed by clip 2

 

 

Interesting. This wasn't the same situation for me; I had one 20 minute clip, spliced it at about 10 minutes, and changed the second clip to 75%. So it didn't butt up to another clip when it lengthened the clip.

 

For those that happen to run into this same problem:

1) Nationalsolo has a possible fix in the post above. It wouldn't have solved my problem, but it may solve yours.

2) Dougie (post #8) writes about another possible work around.

3) My convoluted solution involved making an AviSynth script that inserted the frame pauses I needed, as well as a buffer of scrap video at the end. I used VirtualDub to export this, then opened it in Videopad and put it on the timeline. I then slowed it to 75% and edited/made sure my audio lined up. Then exported it from videopad (including the scrap at the end which is now replaced with solid black) and finally cut the scrap off in Virtualdub.

 

Yeah. Convoluted. But if you ever run into this exact problem, or need some help with AviSynth, it took me a few days of playing around with it but send me a PM and I'll see if I can help.

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Hi

 

"I had one 20 minute clip, spliced it at about 10 minutes, and changed the second clip to 75%. So it didn't butt up to another clip when it lengthened the clip."

 

That works even worse!

Version 3.12

Place a clip on the timeline and cut it in the middle. Now change the speed of the second half to 75%

 

As well as having a black "flash" between the sections, (noted in other posts) the second section gets longer as expected but (on my PC at least) shows no motion until a second or two before going black for the 25% just as you describe. The red IN marker also sets itself in the left hand preview pane for this section of the clip but this is OK as you are actually previewing just the right hand section of the whole clip. but it shouldn't be doing it with the blue OUT marker in the situation mentioned in my posting as the clip in this case had not been split. As I said this must be an error and makes the feature unusable.

 

Seemingly version 3.10 works OK in this respect.

 

Nat

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Looks like I'm in trouble. I tried to create a clip at 30% slow motion and I've had the same proble; extraneous sound length and no video clip or the clip flashing like a strobe after its original length.

 

I've sent a report to technical support to see if they can provide a solution. Seems rediculous that the software can't cope with making a slow motion cli[p.

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Hi

 

Just been checking this with 3.24. ....

 

1) Placed a 12 second clip on the timeline.

No problem. Clip preview OK. (12 seconds) Sequence preview OK (12 seconds) Timeline OK (12 seconds) . Three thumbnails on each.

 

2) Split sequence in centre at 6 seconds to get a Clip1 and Clip2 (although VP still sees it as one clip.)

No Problem encountered. Clip splits into two sections OK.

 

3) Select left hand section (Clip1) for preview.

Clip1 preview shows a duration 12 seconds with the blue OUT marker in the centre at 6 seconds. The thumbnail line shows left half lit up and right half dark. (This is to be expected as VP still sees the new sequence as one clip with only left half of the clip selected and the cursor positioned at 6 seconds).

Sequence preview (12 seconds) unchanged as expected. It is the blue OUT marker as the cursor is at the end of Clip1

 

3) Select right hand section of the split clip (Clip2) for preview.

Clip2 preview shows a duration 12 seconds but with the red IN marker in the centre at 6 seconds. The thumbnail line shows right half lit up and left half dark. (This is to be expected as VP still sees the new sequence as one clip with only right half of the clip selected).

Sequence preview (12 seconds) unchanged as expected. It is the red IN marker as the cursor is at the start of Clip2

 

4) Right click the right hand section and change speed to 50% and Zoom out fully to see whole of sequence.

There is now a problem!

 

I expect to see the right hand section become 12 seconds in length as speed is halved. CORRECT

I expect to see total sequence duration to be 18 seconds........................................... CORRECT

I expect to see the left hand section show 6 seconds (if VP treats it as a new clip) but it remains 12 seconds

Previewing the right hand (Clip2) section shows something different to (3) above. The IN marker is no longer at 6 seconds (where the section actually starts from..its at the 12 second point.

The sequence preview shows that from the 12 second point, (the original length of the clip before it was cut) there are no thumbnails, just blank frames.

The sequence plays to this point and then plays nothing for the section that was lengthened.

 

So it's a bug.

 

Nat

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