Converting Stretched 16:9 vids back to 4:3

[JN-]

Thanks for getting back Sharcs. Is fine no tall and skinny people! However I can no longer produce tall and skinny people either. Was working on this late last night, I know it happened.

I will update if I can reproduce again, away all day so will have another look tonight. Kinda annoying when this happens.

[JN-]

Cannot reproduce. Not important. Re: your comprehensive #56 post. I did come across a wildly off clip and was able to crop and fix it with an adjusted dar. The auto detected dar didn’t work.

This is what I suspect Sharcs is the case in general. Some clips are not all 16:9, but when your syntax is used, (with dars that are close to 16:9, some are ~ 2:1) which doesn’t automatically extract the dar then the clip still looks ok most of the time because even with circles, people, etc it will look ok unless there is a substantive (I always wanted to use that word) difference in the dar.

However, using a method that auto extracts the clips dar is I think a safer more accurate approach.

[Sharc]

Can't tell without seeing your source.
Generally, if your source which you want to convert doesn't have square pixels you may have to set the Pixel Aspect Ratio explicitely in the commandline, like setsar=16/15 for original 4:3 720x576 DVD material in order to play circles as circles. Depends on your source.
Special cases may require manual optimizations though.

[JN-]

“Special cases may require manual optimizations though.” Indeed.

I found that by eyeballing the few odd ones and tweaking the dar from what was auto output I could get what I wanted.

There are merits in both approaches. Your solution is simpler and faster. The other way is slower but may be more accurate.

[JN-]

One last thing, probably.

I had the idea of evaluating a bunch of video clips first in an automated way, not eyeballing, so as to determine beforehand which ones are ok. I thought that if either of the third or fourth items, x, y, was equal to zero 0, then that clip wouldn’t have black borders on all four sides.

This way, by virtue of elimination, then only a smaller subset of remaining clips would need to be checked on tv.

However, it doesn’t really pan out. So maybe my understanding of how returned crop values are returned is mistaken.

I assumeed that if the third value is zero (720:576:0:8) then the clip reaches all the way to the edges, so only top and bottom black borders and no need to crop.

In the same way if the fourth returned item is zero (720:576:8:0) then the useable crop section reaches all the the way to the top and probably also the bottom, with black bars only on the sides, so no need to crop.

When I ran a few samples, that wasn’t the case.

[JN-]

#1. So I did some more testing. I did find that an awful lot of clips that I expect to have no black borders on all sides did have x or y = 0.

#2. However I tested a few of them that have x or y = 0 and several of those did have black borders on all 4 sides. ?

#3. I also tested another few where neither x or y didn’t have a zero value and they had no black borders. But I am beginning to realise that with a relatively small value of 6, 8, 10 for the x axis that thats a very tiny left and right black border.

All eyeballed on tv.

So really the bit I have to figure out is #2.

[leo5150]

i bought Macgyver Bluray collection and media info says its 16/9 but there is black bars on each side how do i encode so there is no black bars? says its 1920x1080

[JN-]

More knowledgeable users here than I on this subject. My 2 cents. The 16:9 includes the black bars. Is the movie a 4:3 AR, kinda square?

My interest here was in dealing with black bars on all four sides. I take it thats not your case?

[leo5150]

top to bottom is full black on sides

[JN-]

So if I understand it its black bars only on the sides, no black bars on top or bottom?

[leo5150]

full top to bottom black on sides

[leo5150]

So if I understand it its black bars only on the sides, no black bars on top or bottom?

no bars on top or bottom just left and right sides

[JN-]

OK.

[JN-]

So my guess is that the MacGuyver is very old, shot in 4:3. ? If so then packaged in 16:9 with the help of black bars.

[leo5150]

sounds right but is there a way to re-encode it?

[Alwyn]

Use AVIDemux

Open your file

Video Output: Set top droplist to desired video codec eg MPeg4 (x264)

Video Output: Configure button: down the bottom, set up your export Rate Control details: there are various Encoding mode options there but for simplicity, from the Mediainfo report, get the total file size of the Bluray and choose Video Size (two pass), then set the file size. Other options are to use Constant Rate Factor ~18 (hit and miss with file size/quality: experiment) and my preferred, Average BitRate; for 1440x1080 I'd use 8000kbps. If the quality isn't what you want or the file size is too big, you can adjust either the CRF or the Average bitrate.

Click OK to go back to the main screen.

Video Output: click Filters button

Click Transform

Double Click “Crop”

Drag the crop box to desired (using top left or bottom right corner handles) to remove the black side bars or drag the timeline marker along to display a good black bars edge, then click "Auto Crop". If you're manually cropping, make sure you only crop the sides. You can crop the top and bottom but you'll then have to adjust your side crops so you maintain the 4:3 ratio.

Click OK

From Transform menu, Double Click Fit to Size

Set Width to 1440 and height to 1080

Slide the Aspect Ratio Tolerance to Set the “Resized to:” value to 1440x1080 (Slider in the middle)

OK

Preview if desired

Close

Set Audio Output as required

Output Format choose MP4 Muxer

Output format Configure button: Force Aspect Ration 4:3, OK

Save As. You'll have a 4:3 video with no black bars.

Note, you don't have to redo the whole movie initially. Just set a small section with the A and B buttons, then Save to test your settings. When you're happy, clear the section and re-encode the whole lot.

[leo5150]

but the bluray rips are 1920x1080

[Alwyn]

Oh Ok, sorry, missed that bit. Give me a few minutes and I'll modify those instructions.

[leo5150]

ok, thanks for helping

[Alwyn]

There you go. I added some details about the encoding parameters (Video Output "Configure").

[leo5150]

any way to save that profile so i can do each video with it? and any way to add nvidia hevc encoding to speed it up?

[Alwyn]

I was hoping you weren't going to ask that! . I'm not aware of any profile-type setup for AVIDemux.

Other users here (ProWo, Sharc) have batch solutions which may work for this situation.

any way to add nvidia hevc encoding to speed it up?

Yes, in the Video Output codec droplist, there are various options. NVidia H264 is there. Give that a whirl.

[leo5150]

anyway to save the profile so i dont have to put it all back in everytime? and is there a option to do batch of videos? they all will be same thing so same crop setup should work for all

[Alwyn]

@Sharc will be able to provide a command-line solution for a batch process.

[Alwyn]

A semi-automated workflow can be set up in VirtualDub 2 using the Crop filter, then File>Save Processing settings, which you can load next time.

For export, you can add individual files to the batch processing list and run the encode for all files at the end.

Let us know if you'd like guidance on that.

Have you used VDub2?

[leo5150]

sure id like to learn that..thanks never used vdub2 though

[Alwyn]

@Leo5150, could you post the Mediainfo report (copy the "Text" view) here of one of your files.

[leo5150]

Unique ID : 113112418141615303730372722421217128553 (0x5518A8C912278C16193449E51E007069)
Complete name : C:\Users\leo5122\Desktop\Video\MacGyver S01E03.mkv
Format : Matroska
Format version : Version 4
File size : 8.16 GiB
Duration : 48 min 14 s
Overall bit rate mode : Variable
Overall bit rate : 24.2 Mb/s
Frame rate : 23.976 FPS
Movie name : MacGyver: The Complete First Season - Disc 1
Encoded date : 2024-02-10 00:48:27 UTC
Writing application : mkvmerge v38.0.0 ('The Silent Type') 64-bit
Writing library : libebml v1.3.9 + libmatroska v1.5.2

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings : CABAC / 4 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 4 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 48 min 14 s
Bit rate mode : Variable
Bit rate : 24.0 Mb/s
Maximum bit rate : 38.0 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.483
Stream size : 8.09 GiB (99%)
Language : English
Default : No
Forced : No
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Commercial name : Dolby Digital
Codec ID : A_AC3
Duration : 48 min 14 s
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Compression mode : Lossy
Stream size : 66.3 MiB (1%)
Title : Stereo
Language : English
Service kind : Complete Main
Default : Yes
Forced : No

[Sharc]

The 2016 TV series is 4:3. When put onto a 16:9 (1920x1080) blu-ray the movie will use 1440x1080 pixels within the 1920x1080 overall frame (canvas) for the active 4:3 picture, so the black side bars are there, unavoidable.
You can crop these side bars away and reencode as 1440x1080 and play as 4:3 on your PC, but the TV player of your 16:9 TV will add those side bars back. If it wouldn't add them back the picture would get stretched horizontally ("fat people" look).
If you don't want the black bars on your 16:9 TV you would have to replace it by a legacy 4:3 CRT TV, or mount some curtains (like in cinemas) in front of your TV to hide them.

[Alwyn]

@Sharc, there is no need for pillarboxing. In fact, it is a nuisance on a 4:3 screen, or a phone/tablet screen that is held in Portrait mode. Nor is it required for YT.

Adding bars sounded like a good idea at the time (and I fell for it) but now they are just not necessary and I, for one, am re-encoding all my pillarboxed videos as I come to them back to true 4:3 videos.

Putting it another way: "Why would you?".