Lost or repeated frames in Pro X4

[Milos]

I have noticed now that in my post on Friday Sept 02, 2011 6:45 pm I made a mistake in the number of frames, I wrote:
original 2144
rendered 3136
It would mean that some frames (8) in the rendered files were missing, but that is wrong. Here is a correct number of frames:
original 3134 (instead of 3144)
rendered 3136 (it means +2 compared to original)
As I remember my experiments with older versions of Videostudio, it always add a few frames (video freezes for a very short period of time). Sometimes even happened, that it went forward, than 2 frames backward and again forward. I always worked with SD mpeg2, not HD.

[Trevor Andrew]

Hi Milos

Having read your comment on going forwards and backwards I took particular note.
I have run a few more tests there does seem to be an issue when using titles.

Now this is a little difficult to explain.
I used colour clips to produce vertical boxes using Pan & Zoom allows me to view/identify each frame.
This became my source video file, mpeg2 500 frames.

Add titles and rendered the project to standard Mpeg2 (500 frames) causes the total frames to increase by two. (502 frames) Rendering without using Smart Render does not show this abnormality.


This is what I see…………
Whilst playing the video the frames shift out of place by 2 frames then shift back in place.
This happens at approximately five frames after the title has finished. (no title animation)
The video continues to play ok, repeating the above on all titles up to the last title where the shift remains leaving the video two frame larger than the original.

I know two frames are such a small amount, so is it worth the effort?
I haven’t explored the effect on audio, however I don’t think I would be able to hear any sync’ problems.

I tried batch converting the VSP file, this proved ok, so I guess Batch Convert does not use Smart render, there is no option to select/de-select SR.

This sounds a little like the Blip problems related to HD types, if I remember these occurred after transitions?

I really don’t have a solution, if you are able to see the problem as blips during playback then I can only suggest NOT using Smart Render

Milos I can e-mail the test files I used if you are interested in seeing them.
Send me a PM.

[Milos]

Hi Trevor,
thank you very much for the work you have done, you must have put a lot of effort in it. When I browsed web searching whether I am the only one having problems with the issue we are talking about I came accross the messages concerning blip occuring after transitions you have written about. It is a pitty because very useful Smart rendering function is due to this problem limeted to simple cuts. I know that 2 frames are not too much, but when you play the video, you can always see the point where renderings ends, because the jerking is visible ( not too much, but is ). I am not shure what decission to make but I am afraid that although I like VS, I will probably finish by PowerDirector. I tried it with smart rendering and the transition between titles and the original was (for me) absolutely invisible. Once more thanks a lot for your support and a time you spent solving my problem. And of course I am interested in the test files, I would be glad to see what happens.
Milos Sladecka

[Trevor Andrew]

Hi Milos

At present I have tested MPEG2 types, given time I will run a test using DV-Avi………….

You seem to have two issues, the extra frames/blips created after the titles and a quality problem.

Disabling Smart Render should not show any quality reductions sufficient enough to be instantly recognisable.

Yes the video will reduce in quality but would take several re-codes to be noticeable, even with a critical eye.

My first thoughts are 2-Pass encoding. This should be used, with thin turned off there will be some quality problems.

So are you using 2-Pass encoding?

[Milos]

Hi Trevor,
I am sorry for not writing for a such a long time, but for 2 weeks I had problem with my internet connection.
I have got only one problem - extra frames after titles. Concerning quality I am aware that 2pass encoding brings better results than 1pass but I have not tried it. The reason is that I want to avoid recompressing of the video in all. Although the loss of quality is little, on principle why I should go trough recompressing process of the whole video and spend extra time for it, when there is a simple solution - smart rendering. The best video is surely non recompressed video. And if Corel is not able to do it, I will try another soft.
Thanks,
Milos

[Trevor Andrew]

Hi Milos

I really do not understand your thinking……………….

You have a problem with extra frames after a title, yes I confirmed that this is what is happening.
Disabling Smart Render cures this issue. I can only advise that you report this to Corel Support.

Smart Render issues……..
Its not a new thing, there have been some problems for some users in the past going back to the earlier versions, and the recommendation to disable Smart Render has helped.
Most users do not have a problem.

Fully rendering some types of video will reduce the quality, but I doubt we can see the quality loss in the first render. You would have to go through 3 or so generations to see any quality issues.

Two Pass

You say that you are aware that 2 Pass encoding improves quality, yet you still refuse to try this option, I find this quite unbelievable.
You will see a definite improvement when using 2 pass. Other software programs will use “2 pass”

If you do not use “2 pass” then change the bit rate to Constant instead of Variable.
Using 2 pass does not take twice as long, I doubt if you will see the time difference.

We can only advise you on what we think is a solution.
We would assume you would apply our recommendations to see if you can improve your quality.
Do not be afraid of fully rendering the video, the encoders are very good at their job.

As for the time taken to do the job, who said Video Editing was fast.

[Milos]

Thanks for your reccomendation, I give up and I am going to fix my problem according to your advice.
Milos