It's been a while since I had any idea how to do these things so I could use some help.
Attached are two shots, a SD (720x480) and an HD (1916x808). Can someone please look them over and advise how to properly blow up the SD one to match the HD shot?
I'd imagine cropping would be involved but yeah, I don't know.
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Thread: How to match the AR of SD vs HD?
How were the captures made? How did you get the original source video onto your computer? What is the frame rate of the original source? Was it taken from a DVD? Movies transferred to digital DVD are almost always telecined; hopefully you did not resize a telecined source. A little short on info here.
In any case, 1916x808 is non-compliant for BD or AVCHD disc even for a 2.35:1 movie without some letterbox padding (if it's not encoded with that border, it will play that way neveretheless). It should resize to about 1920x816 with top and bottom borders to get a 1980x1020 frame with a 2:35 image inside it
I'd suggest that you try for 1280x720 HD (1280x544 image) with SD source if you simply must resize. That format can use 23.976 fps non-telecined film frame rate. Get the desired image size by dividing the encoded frame width by 2.35. The resulting height should be evenly divisible by 8. for 1280x720, it would be 1280 / 2.35 = 544 for a height that is mod-8.
BD and AVCHD specs: http://www.videohelp.com/hd#tech
Last edited by sanlyn; 16th Sep 2013 at 09:25.Our inventions are wont to be pretty toys, which distract our attention from serious things. They are but improved means to an unimproved end. -- Henry David Thoreau
You can get close simply by cropping the top and bottom black borders and resizing what's left to 1916x808. If you need more perfect results than that you'll have to spend a lot of time working out the details.
The SD and HD captures were both "copy output frame to clipboard" in VDubMod. The SD taken straight from the DVD's VOB. The HD version is an iTunes rip; no re-encoding... I used Requiem to directly strip the DRM. I then pasted them into Photoshop and saved as a bitmap. The HD version really is 1916x808, which makes me think they kind of "pre-cropped" it for streaming...? The DVD's frame-rate: 23.976. The HD frame-rate is the same. I didn't resize anything.
The problem with cropping the top/bottom is that I can't seem to pinpoint where the borders truly end and the picture data begins. Even if zoomed in to an outrageous degree, the borders seem to melt into the picture :/
You can start by using the same frame (these aren't the same frame)
It looks slightly warped, so it will be difficult to match perfectly
What is this for ? / Why are you doing this ?
I agree they are different frames.
I'll start with being more careful and using matching frames.
This is basically just an experiment to see what kind of difference/improvement there is when taking clip A in SD then switching to the same clip in HD, within the same merged video clip.
If we assume there was no camera motion between those frames, and you only want to get a "close" match; in RGB mode (you can't crop by non even numbers in YV12) :
Use a script like this to compare:
hd=ImageSource("HD-1916-808.bmp") sd=ImageSource("SD-720-480.bmp").Crop(1,55,-1,-60).Spline64Resize(1916,808) Interleave(hd, sd)
Last edited by jagabo; 16th Sep 2013 at 22:06.
Okay. Thanks. That did work well for a still image. Now, what if I'm trying to have a certain number of frames from clip A playback before switching to clip B's playback? Same idea, just not with a still image. Clip SD lasting for let's say 2 seconds, then switching to the HD's 2 second clip...?
Interleave() works with videos. In fact, the earlier example works by opening two images as video clips. It's always frame by frame though. If you want 2 seconds of A and 2 seconds of B you can use Trim() to snip out a few seconds of each then append them:
video1 = WhateverSource("video1.ext").Trim(video1, 1000,1049) # 2 seconds of a 25 fps video video2 = WhateverSource("video2.ext").Trim(video2, 1000,1049) # 2 seconds of another 25 fps video, doesn't have to be the same frame numbers video1+video2 # append the clips
Thank you, by the way. Despite how long it's been, I feel it's rude not to come back and say thanks for showing me something that worked.