Choppy output (any codec!!!) Bug?

[TheMajor]

I take screenshots from Enemy Territory (a game). 24 screenshots per second. I import them to VirtualDUB and compress it to DivX (or something else). This results in a nice and smooth video.

Now, if I wanted to insert some transitions and stuff I would export an uncompressed video with VirtualDUB and open it with Media Studio Pro 8.

When I have finished editing the video I have to create a video out of it; but no matter which compression I select in MSP8 (uncompressed/divx/etc), the output is never smooth! it's always slightly choppy.

The RAW files I export with VirtualDUB are smooth; I checked it.

Example files:

Import screenshots to VirtualDUB -> Compress to DivX
Result: http://themajor.no-ip.org/Base_Race_by_TheMajor.avi

Import screenshots to VirtualDUB -> Save uncompressed -> Import in MSP8 -> Create uncompressed video -> Compress to DivX using VirtualDUB
Result: http://themajor.no-ip.org/Base_Race_2_by_TheMajor.avi

And BTW, it is not choppy because of the higher resolution; I recompressed the first movie (the smooth one) using MSP8 and it resulted in a choppy movie as well.

Also tried saving as DivX straight from MSP8; same problem.

The first movie has been resized using the feature in DivX. The second movie has been resized using the "filter" method in VirtualDUB.

[TheMajor]

I just did some testing. Using the "resize" filter or DivX resize doesn't make any difference; both are smooth.

I create two example videos; both are the same movie so you can clearly see the difference.

Smooth (VirtualDUB only): http://themajor.no-ip.org/VirtualDUB.avi
Choppy (Created with MSP8): http://themajor.no-ip.org/MediaStudio.avi

[Gorf]

Well the target video is 30fps from a source of 24, so you're going from

abcdefghijklmnopqrstuvwx (24 frames in one second)

to

aabcdeefghiijklmmnopqqrstuuvwx (30 frames in one second)


Keep your framerates the same, or try to do "pulldown" in DivX (although you probably only need this if you're going to TV - for the web, just stay at 24fps).

[TheMajor]

I am aware of that. But that is not the problem. Since the source is seperate screenshots I can select any frame rate I want; it wouldn't matter. It just makes it playback faster than real-time.

In other words, nothing has been converted; all I did was set the amount of source frames to display per second.

[Gorf]

I am aware of that. But that is not the problem. Since the source is seperate screenshots I can select any frame rate I want; it wouldn't matter. It just makes it playback faster than real-time.

In other words, nothing has been converted; all I did was set the amount of source frames to display per second.

So how come in Mediastudio.AVI every fifth frame is repeated?

[TheMajor]

So how come in Mediastudio.AVI every fifth frame is repeated?

It is? Why does it do that? I always select "frame based source" and I select the same frame rate (29.70 mostly).

[Terry Stetler]

TheMajor;

Please fill out your profile, especially the system specs. That out of the way....

The 24 ==> 29.970 fps conversion is called 'Telecine'. 24 fps is the normal frame rate for movie film and many video games, as you have discovered. It is also the frame rate used on most NTSC DVD's. More on that later.

Please read this Wikipedia article, especially the portions labeled;

3:2 pulldown (technically, 2:3 pulldown)

Telecine judder

http://en.wikipedia.org/wiki/Telecine

IF your goal is putting 24fps video on DVD then there is no reason for the conversion; 24 fps is DVD legal for NTSC players. Just set your DVD authoring programs project settings to 'do not convert compliant MPEG files'. This setting is in all Ulead DVD programs.

When you burn the video will be passed through intact, though the audio will have to be 'muxed', meaning multiplexed to the video stream. When played the DVD deck will do the telecine itself.

You do, however, have to export the MSP project to 24 or 23.976 DVD compliant MPEG, with chapter cues if you desire to create a chapter menu.

[Gorf]

So how come in Mediastudio.AVI every fifth frame is repeated?

It is? Why does it do that? I always select "frame based source" and I select the same frame rate (29.70 mostly).

It's because you are selecting frame-based that it is repeating the entire frame. How else can it work out what to add?

I think you might be confusing clip speed and frame rate.

If you just re-speed your 24fps footage to 30fps by speeding it up 25%, you won't be adding or removing frames, but what used to happen in 1/24 of a second is now happening in 1/30th. A one-minute sweep of a watch hand will now take 48 seconds but will still contain 1,440 frames.

If you simply change the frame rate, you have to add or subtract frames (depending on the frame rate) so that what happens in a minute still takes a minute, but uses more (or less) frames. your one-minute sweep will still take one minute, but will contain 1,800 frames.

As terry said, 24fps is "legal" for DVD, but it's also legal for the web. You only need to change the framerate if you're putting it on tape.

[TheMajor]

I don't really understand. When I import the screenshots in VirtualDUB, it has no way of detecting how many of those screenshots should fit in a second. So I have to enter the frame rate myself. If I enter 24fps it will take 24 of those frames per second. If I enter 30fps it will play 30 of them; making everything look sped up.

Now, if I entered 24fps in VirtualDUB, then open the uncompressed (progressive) video in MSP8 and want to save it again; which settings to I use?

[heinz-oz]

Do you actually know what it is, exactly, that you want to do? Why do you want to load all this into MSP?

Is it because you want to create a DVD out of it? If your answer is yes, forget all that crap you stated before. DVD does not allow you you use any frame rate at will. PAL is 25 fps and NTSC is 29.97 fps. If you want your clips to run at a realistic speed, that will be what you have to use.

[Gorf]

What do you use to get the screenshots out of "Enemy Territory"? I'm thinking FRAPS or something similar. If you're using Virtualdub, I wasn't aware it had that capability.

Whatever you're using, you said at the top of the thread that you're grabbing 24 frames a second. If you bring this into (say) MSP as a sequence of stills, you can tell it that each still lasts for one frame, so in those circumstances the speed will change depending on the framerate of your project - a 24fps project will be "realtime", a PAL project will speed up the action by 4% (25/24) and a NTSC project will speed up the action by 25% (30/24).

If you bring it in as an image sequence or video file or some other mechanism that has an inherent frame rate, then when you drop it on the timeline, the framerate may be changed. This means that if the project is 15fps, you lose almost every other frame. If the framerate is 30fps, you gain a copy of every fifth frame.

[Gorf]

...DVD does not allow you you use any frame rate at will. PAL is 25 fps and NTSC is 29.97 fps. If you want your clips to run at a realistic speed, that will be what you have to use.

DVD-compliant MPEG-2 can be encoded at 24fps, 25fps or 29.97fps. The player will decode to 25fps or 29.97fps (it performs a realtime 2-3 or 2-2 pulldown).

It's pretty much academic, though, as the frame sizes we've seen so far from TheMajor are not DVD compliant, and as yet we've had no indication that he's even going to DVD.

[Terry Stetler]

That's why I said "IF your goal is putting 24fps video on DVD".

For the record....NTSC legal DVD;

352x240 (MPEG-1 or 2) or 352x480, 704x480 or 720x480 MPEG-2

23.976, 24 or 29.970 fps (MPEG-1 29.970 only)

Dolby (preferred), MP2 (secondary preferred), PCM, DTS (not supported by all decks) audio.

If he's using an image sequence (sounds like it);

The files must be sequentially named: file0000, file0001 etc.

In VirtualDub the Frame Rate dialog (CTRL-G; or Video/Frame Rate on the menu) can be used to define a frame rate for the image sequence. Every option conceivable is in there, but I'd use 'Source Rate Adjustment/Change to'.

In MSPro image sequences can be imported directly. In the 'Load Video File' dialog choose the *.UIS filetype then click "Options". In here you select the first image in the sequence, set the frame rate, the name & location of a *.uis proxy file etc.

Once finished you exit Options, load the *.uis proxy and the image sequence comes in with whatever frame rate you set. Presuming the project settings & export settings match this frame rate it will not change.

[TheMajor]

Thanks all for your replies.
The video's will not be used for DVD; they are for playback on computer only.

Enemy Territory has a built-in feature to capture the screenshots; it saves them as TGA files.

I will see if I can load the stills in MSP8 directly.

If I understand correctly I have to set the "project settings" in MSP8 to match the source file if I want to keep the same frame rate?

[TheMajor]

I imported the stills in MSP8 directly.
This is the video: http://themajor.no-ip.org/TEST.avi

I think it is smooth, but I need to do some more testing to know for sure.