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-   -   Cropping and resolution in Handbrake, which is right? (https://www.digitalfaq.com/forum/video-editing/7440-cropping-resolution-handbrake.html)

Turmoil 07-13-2016 10:19 AM

Cropping and resolution in Handbrake, which is right?
 
3 Attachment(s)
Hello,

I read several times about PAR, DAR, resolutions, anamorphic transcoding, square and rectangular pixels,... I still don't understand it as much as I would need to feel comfortable to judge, if I am choosing the right settings etc. - so instead of investing more days in it and feeling dumb and dumber, I decided to just ask here.

I have a digital capture of my TV (that I transfered from my PVR to my computer) and it was an old 4:3 movie that has bookends added to fit a 16:9 resolution.
Now as I am encoding it on my computer in Handbrake I wonder, if
a) I'll just let it stay that way
or
b) cut off the bookends, so I would have 4:3 full screen on my old 4:3 Tube TV and the computer-screen or a 16:9 TV would add new bookends itself anyway.

If I am correct, after cutting I should get 960x720 (for 4:3). I used this http://calculateaspectratio.com/ to calculate it.
But, if I do this I have to cut off a few of the pixels at the edges that are part of the movie and not the bookends anymore, to get this exact resolution. When I let Handbrake decide I get some strange resolution.

look at the screenshots to understand my problem

sanlyn 07-13-2016 10:50 AM

960x720 won't work correctly with your 480-height 4:3 CRT unless the player device downsamples to 640x480, or you use a standard anamorphic size and encode for 4:3 display. Your CRT TV displays only 480 horizontal lines, an part of the image is masked by overscan.

Turmoil 07-13-2016 11:16 AM

Oh, I forgot to mention it is PAL. SD-channels send with 720x576 here and I thought 4:3 Tubes are that way. At least the Manual of my satelite receiver (that has the build in PVR) says for 4:3 Tube TVs one should select 576p.

Nevertheless Handbrakes own suggestion of 976x716 can't be right either or would it fit any known resoltuion? Does Handbrake maybe confuse square and rectangular pixels, because for some content it sugguests to set anamorphic on and the resolution is displayed as 768x576.

I don't want to make it smaller than the source is. The source is 1280x720. Since the 1280 contain black bars to the left and right, I would like to cut these away, hence I should get a 4:3 resolution where the height is still 720. At least that is what I am aiming at.

sanlyn 07-13-2016 08:55 PM

Quote:

Originally Posted by Turmoil (Post 44897)
Oh, I forgot to mention it is PAL. SD-channels send with 720x576 here and I thought 4:3 Tubes are that way. At least the Manual of my satelite receiver (that has the build in PVR) says for 4:3 Tube TVs one should select 576p.

Nevertheless Handbrakes own suggestion of 976x716 can't be right either or would it fit any known resoltuion? Does Handbrake maybe confuse square and rectangular pixels, because for some content it sugguests to set anamorphic on and the resolution is displayed as 768x576.

I don't want to make it smaller than the source is. The source is 1280x720. Since the 1280 contain black bars to the left and right, I would like to cut these away, hence I should get a 4:3 resolution where the height is still 720. At least that is what I am aiming at.

From old notes in an electronics textbook I pasted a copy of this, which is math fact: "PAL CRT has a horizontal frequency of 15.625Khz and a vertical frequency of 50Hz. With those timings, maximum resolution you can fit on a 4:3 screen is in the order 800 x 600, not counting a possible overscan area."

Apparently you've made up your mind anyway, which leads one to ask, why haven't you already tried it? Along the way, you might consider that 976x716 is neither mod-8 nor mod-16 vertically. All standard video resolutions (including 800x600) are at least mod-8, most are mod-16 (except 1080i and 1080p, which are not mod-16). 976x720 is a safe mod-16 frame. So encode it as square pixel and find some way to feed the signal to your CRT. If you want something anamorphic to encode at 4:3 DAR, you'll have to deinterlace or inverse telecine before you can resize to an anamorphic format that a player device can read properly. In any case, to get that video to display as 4:3 on your CRT you'll have to re-encode your original whether you crop or resize.

As I haven't used Handbrake in several years (far too limited, and sucks at deinterlace and resizing), I can't tell you how its interface works nowadays.

sanlyn 07-14-2016 10:54 AM

For what it's worth, there is more than one way to fix things for different playback scenarios....

I have plenty of HD 1920x1080 PVR recordings off my HD cable box, a few 720's, of 4:3 movies. Here's what I do to make a DVD or 4:3 video for DVD or HDD playback on my OPPO and an old CRT:

- Open the video in Avisynth.

- If the program is interlaced, it's deinterlaced with QTGMC. If it's telecined, it's inverse telecined with TIVTC.

- In Avisynth, crop off the black side borders and resize the video to 720x480 (NTSC) using any of several low-pass filters and Avisynth resizers (Spline36Resize works pretty well). An Avisynth 16-bit dithering filter often helps to get cleaner color and avoid resizing artifacts. If the original was interlaced, it's reinterlaced in Avisynth. If it has been inverse telecined for 23.976 playback, 3:2 pulldown will later be applied in the encoder for 29.97 DVD or SD BluRay. You can't use square pixel output for those two formats.

-Save the output as lossless compressed Lagarith YV12 AVI.

-Encode with my MPEG or x264 encoder for standard def 4:3 DVD or SD BluRay. Apply soft-coded telecine flags if necessary.

For PAL you can adjust resizing, interlace, telecine, etc., for the playback you want. There's no way I would do this in Handbrake or similar apps.

Turmoil 07-14-2016 05:12 PM

Quote:

Originally Posted by sanlyn (Post 44904)
Apparently you've made up your mind anyway, which leads one to ask, why haven't you already tried it?

Sorry, if I have appeared to be a know-it-all-while-not-having-the-slightest-idea-of-anything kind of person and appeareed as if I am not accepting you answer or saying it is wrong. I just didn't understand and was wondering.

Regarding testing it myself:
I did and used the three settings I had made a screenshot of. I encoded a small bit with these settings and then watched them on my CRT (the media got fed into a satelite receiver with PVR/mediaplayer). The result was, that I get
1280x720 = the Handbrake encode was same as source that was recorded on my PVR
960x720 = fitting the 4:3 of course, but small parts arround the picture are hidden, obviously due to being in the overscan area.
968x716 (as sugguested by Handbrake itself) = see 960x720

BUT there is a difference though between the last two. Of course there is a different amount of picture content lost in the overscan area, but the difference is small.

I have an idea now. I will try to find the numbers that I need to move the picture content at the borders out of the overscan area. I know that is not how CRT was meant to be, but I'd like to see the whole picture content, even, if it wasn't even concidred action save by the director. Th eproblem will be to make sure that the numbers devide by 4:3 and fit rectangular or square picels. I have yet to find out, if the mediaplayer of the PVR does interpolate/scale the picture anyway, so that I don't have to differentiate between PC-monitor, 16:9 LCD-TV and 4:3 CRT.

Other thoughts.
The TV channel that sent the content is available in SD and HD. I realized in the past that they send a picture without bookends on SD (so the 16:9 TV adds them, the 4:3 will have fullfillingimage). ON HD they send bookends added to the content (which is an old 4:3 movie) and it will appear as 16:9 on the 16:9 TV, on the 4:3 TV you will have a black frame arround he picture (i.e. letterboxes AND bookends, as if the picture is made smaller and put into the center).

Unfortunately I didn't think about that the day I recorded it. I recorded the HD stream (I should have also recorded the SD stream on the rerun in the night, to have a comparison).

I understand that it probably is right, what you say about Handbrake. Resizing was terrible in version 0.9.4, however I think they changed something in the latest version 0.10.something, still not intuitive to a dumb person like me. However, I understand, the whole attempt by me will not be successful as long as I don't count in all factors such as telecining and what you mentioned.

I will maybe just opt for the easiest option "keep aspect ration, anamorphic none" and output same as source. Since probably there is no way of ever sorting this out correctly with my limited cerebral capabilities. I am bad at maths, so I shouldn't think about the whole issue anyway and just eat what Handbrake does.

PS: forgive my bad spelling, I am actually very good at linguistic stuff, but its late and my head aches.


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