Need help: 50% HD to SD Slow Motion

johnmeyer wrote on 5/15/2007, 4:16 PM
I'm doing golf swings for the local high school golf team. Shot them in HDV using my FX1, but delivery is 4:3 NTSC SD on a DVD.

I could have sworn that I read somewhere of a way to convert each 1080i field into a frame of 1/2 resolution HDV. Since the square pixel resolution of HDV is 1920x1080, and the square pixel resolution of SD NTSC DV is 654 x480, I can halve the HDV resolution and still have more than I need for SD delivery. I should therefore be able to get pretty nice looking video.

Problem is, I can't figure out how to do it. I have played around with Interpolate and Blend and None for deinterlace, but I must be having a "senior moment" (actually the whole day has been like that).

Anyway, I'd sure appreciate some help. The following snapshot shows what I'm trying to avoid. I'd like to take those two fields you can see in the pic below (look at the clubhead), and turn them into frames of 1/2 the resolution. The other thing I was hoping to do is to produce a series of freeze frames of each moment in the swing. I tried disabling resample and setting playback to 1/16 normal speed, but then I ended up with a series of individual stills which look exactly like the following photo. Yeech!

Thanks!



Comments

Coursedesign wrote on 5/15/2007, 4:25 PM
I don't think you can do it in Vegas.

If you think about what "Interpolate and Blend and None for deinterlace" are supposed to do, it should be clear why the output looks like the YouTube violinist.

Time to pull out Virtualdub/AVISynth and you'll have what you want in a jiffy.

johnmeyer wrote on 5/15/2007, 4:39 PM
Time to pull out Virtualdub/AVISynth and you'll have what you want in a jiffy.

Thanks!! I have them both and know how to use them. I even have the scripts. However, I don't yet own Cineform and was trying to avoid creating uncompressed HD files. However, you may be right. Certainly I will get the best possible result going that route.

I have found some ideas in this thread:

Got one for you... 30i to 60p

I'll see if those ideas get me where I want to go ...

fldave wrote on 5/15/2007, 6:37 PM
I think you are talking about VirtualDub, deinterlace (internal) filter, "Unfold Fields Side-by-Side" option.

It creates a 2880x540 avi output, each field an actual 1440x540 picture side by side in a single frame.

You can then add a filter after that for "Resize (internal)" and pick the Lanczos3 option in the filter mode option. Or if the size was OK, then you would crop either the right or left side of the avi out of the final output.

Once it is resized, you can add the deinterlace filter again and select the "fold side-by-side fields together" to re-interlace the footage.

What I think you want to do though is to drop one of the fields altogether??? I think the Vegas project deinterlace option "Interpolate" simply drops a field completely.

Read to the very bottom of the post for the correct answer???
johnmeyer wrote on 5/15/2007, 9:33 PM
OK, I finally got what I was looking for.

To convert fields to frames (sometimes called 60i to 60p) and halve the vertical resolution (which is OK when going from HDV to SD), set the event playback speed to “0.5”. Set project properties to progressive and set project deinterlace method to “blend.” Keep resample at “Smart Resample.” When rendering to MPEG-2, start with the DVD Architect template, and then make sure to change output to progressive.

Unfortunately, this means EVERYTHING, must be rendered progressive. I still haven't figured out how to put this kind of slow mo in the middle of a standard interlaced 4:3 SD MPEG-2 project. Still working on that ...
Coursedesign wrote on 5/15/2007, 10:41 PM
Blech!

...and the render times should be an order of magnitude longer with that method, plus the quality is likely to be not quite as good (although for golf swings this may not matter).

I just can't help thinking that if you use a proper tool that lets you discard every other line and every other pixel on the remaining lines, you'd get better quality, and normal playback speed to boot.
riredale wrote on 5/16/2007, 12:21 AM
John, you don't need Cineform as the intermediate to carry over to VDub. Last week I started a thread here that sang the praises of a new codec (well, new to me anyway) called PicVideo M-Jpeg by www.pegasusimaging.com.

When used at the compression level of 19, images making the round trip to VDub and back look totally lossless to me, and at this level the files are not much larger than Cineform files. Much smaller than HuffYUV. The codec is just $28. VDub just eats them up--I've spent the better part of the past week running dozens of clips through DeShaker, and the M-Jpeg codec worked beautifully.
DJPadre wrote on 5/16/2007, 12:30 AM
i understand riredale excitement here, however huffy YUV is a 422 codec and starting with 420 wont make a difference if u use it as an intermediate. fair enough its cheap, however huffy being what it is, renders out much faster than mjpeg

ive done numerous tests and the SOny, Huffy and cineform codecs are the best when it comes to throwing things across numerous applications