Recorded TV MPG file repeating frames.

[sambat]

I was using DgIndex and an Avisynth script in VirtualDub to look at a TV recording; it has four repeats of each frame.
Usually recordings from this station show a two repeat sequence.
Can anyone tell me why they would be different.

avi clip from .m2v.
http://www.mediafire.com/?8376av57et9csga

[Nelson37]

The type of recording hardware and the Avisynth script might be helpful in determining what the problem is.

If this is an animation, many of these are only 12 FPS with all dupes removed.

[sambat]

Thank you for responding.
It's a sitcom, not an animation and there isn't a problem - it's that I was comparing it with a recording of 'V' from the same station and wondering why the difference.

When 'V' (59.94fps) is converted to avi for my standalone player, the sound goes out of sync unless the frame rate is changed to 29.97fps.
Staxrip does it by setting the field filter to 'select even'.
From my view nothing is lost, since the odd and even look the same.
Then I look at this other recording and see the different pattern and wonder why.

[jagabo]

It's because the frame rate is 119.88 fps.

What's your AviSynth script look like? It looks like the video was bobbed twice.

And what's with the weird aspect ratio?

[sambat]

mpeg2source("ch72.d2v")
assumetff()
#assumebff()
separatefields()

Here's the source .wtv information.


[Attachment 6082 - Click to enlarge]

[jagabo]

Your source was progressive 1280x720 59.94 fps with every frame repeated twice. Then SeparateFields() is splitting each of those frames into two half height frames, doubling the frame rate and distorting the aspect ratio.

What your you trying to accomplish? Just a conversion to Xvid? Then all you need is:

mpeg2source("ch72.d2v")
SelectEven() #or SelectOdd()

You might crop away the black borders too:

mpeg2source("ch72.d2v")
SelectEven() #or SelectOdd()
Crop(160,0,-160,-0)

That will leave you with a 960x720 frame (4:3 aspect ratio) with small black borders. Crop a little more if you want to remove all the black borders.

[sambat]

Your source was progressive 1280x720 59.94 fps with every frame repeated twice.

Why is it repeated in the one case - but not in the one below.

http://www.mediafire.com/?u19cftex5awy73v

I'm not interested in processing the videos - I wish to know the reason for the differences in the sources since they are recorded from the same HD channel.

[jagabo]

The first video was made from a source that only had 30 unique frames per second. (Because of the low resolution I suspect it was originally 480i with 60 unique fields per second, deinterlaced to 30 frames per second, then upscaled and frame duplicated to 60 frames per second.)

The second video was made from a source with 60 unique fields or frames every second. I suspect it was originally 1080i (60 unique fields per second), bob deinterlaced to 60 frames per second, and downscaled to 720p for broadcast.

[sambat]

That's interesting.
The first one is a sitcom, 'That's so raven' and the second is 'Entertainment Tonight'.