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Old 23rd August 2016, 01:48   #1  |  Link
agressiv
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SAR Question

Trying to figure out what SAR to use when encoding 4:3 video with DVD as the source.

I'm cropping 8 off the left and right which is largely unused or malformed (so it's 704x480). Normally, I set the SAR to 8/9, and the output video would be 704x540. It looks the *same* as the source except for the crops on the side. However, MPC-HC reports this as SAR 176:135.

I've read that I should instead be using SAR 10/11 for 4:3 sources when you crop 8 off the sides.

However, the output size is effectively 704x528, and looks scrunched vertically compared to the original. However, it does report as 4:3.

I know there have been plenty of discussions on this, such as here:

http://forum.doom9.org/showthread.ph...27#post1058927

So, is the original wrong for displaying at 4:3 with the lack of information at the sides? Maybe there is no definitive answer, but I'd love to know what people are using as a SAR when they have 704x480 content.
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Old 23rd August 2016, 07:28   #2  |  Link
Ghitulescu
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It would be helpful to know what exactly are you "capturing and editing" ...

Because it appears you did the other way round.
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Old 23rd August 2016, 07:56   #3  |  Link
Sharc
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When your source is a 4:3 NTSC DVD with small black borders left and right, its PAR is probably ITU i.e.4320:4739 = 0.909709034.

- When you encode to mpeg4/AVC and crop the 2x8 borders the SAR should be 10:11 for the cropped 704x480 picture
- When you want to encode blu-ray compliant you should leave it as 720x480 and encode at SAR 10:11, and probably get a 2.4% AR error on HW player/TV,
or crop to 704x480 and resize to 720x480 and encode at SAR 10:11 (for blu-ray compliance).

For better advice upload a sample.
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Old 23rd August 2016, 12:02   #4  |  Link
tebasuna51
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Quote:
Originally Posted by agressiv View Post
Trying to figure out what SAR to use when encoding 4:3 video with DVD as the source.
Quote:
Originally Posted by Sharc View Post
When your source is a 4:3 NTSC DVD with small black borders left and right, its PAR is probably ITU i.e.4320:4739 = 0.909709034.

- When you encode to mpeg4/AVC and crop the 2x8 borders the SAR should be 10:11 for the cropped 704x480 picture
To avoid confussion first use standard names.
If we accept https://en.wikipedia.org/wiki/Pixel_aspect_ratio :

DAR = SAR x PAR

SAR = Storage Aspect Ratio (here after the crop 704x480)
PAR = Pixel Aspect Ratio (the --sar x264 parameter 10:11)
DAR = Display Aspect Ratio (on screen 704x528, DAR 4:3)

If you want the --sar parameter for x264 the standard name is PAR, not SAR.

Quote:
Normally, I set the SAR to 8/9, and the output video would be 704x540. It looks the *same* as the source except for the crops on the side. However, MPC-HC reports this as SAR 176:135..
Like Sharc say when you need crop to 704 "is probably ITU", but Brother John say also:

"... you have virtually no chance to find out the real DVD PAR (i.e. the PAR used in the mastering process) for sure. It might be generic, it might be ITU. Black bars left/right are an indication for ITU, but you canít be certain. Also the absence of bars might mean generic, but itís no proof either."

Then seems than your DVD is a Generic NTSC 4:3, and seems right use a PAR of 8:9 (with the x264 parameter --sar 8:9) to obtain a screen image of 704x540 than is informed correctly like a DAR 176:135
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