MeGUI Force Input DAR

[VideoFanatic]

MeGUI now has a Force Input DAR in the video tab of One-Click config. I don't want to set an option here. I prefer to use this x264 command line flag: --sar 1:1
If I set Force Input DAR to Auto detect later will it use my x264 command line flag?

[hello_hello]

Force Input DAR sets the Input DAR or the display aspect ratio of the source. It'll effect any resizing calculations but not the output pixel aspect ratio, unless anamorphic encoding is enabled, and I'm pretty sure if you set --sar in the encoder configuration it'll over-ride any SAR ratio MeGUI would otherwise set anyway, assuming anamorphic encoding was enabled.

You might use Force Input DAR if you had a source for which the wrong display aspect ratio was set, or for which MeGUI detects the wrong display aspect ratio. MeGUI's resizing calculations will then be based on the Input DAR you set rather than the incorrectly detected one.

[hello_hello]

Deleted double post.

[VideoFanatic]

Force Input DAR sets the Input DAR or the display aspect ratio of the source. It'll effect any resizing calculations but not the output pixel aspect ratio, unless anamorphic encoding is enabled, and I'm pretty sure if you set --sar in the encoder configuration it'll over-ride any SAR ratio MeGUI would otherwise set anyway, assuming anamorphic encoding was enabled.

You might use Force Input DAR if you had a source for which the wrong display aspect ratio was set, or for which MeGUI detects the wrong display aspect ratio. MeGUI's resizing calculations will then be based on the Input DAR you set rather than the incorrectly detected one.

I still don't understand. If I'm setting the output SAR in x264 then is the input DAR ignored?

[hello_hello]

No it's not necessarily ignored. The Input DAR is the starting point for MeGUI's resizing calculations (assuming you're resizing). For example if you open a 4:3 PAL DVD and it's correctly detected as 4:3 (it's rare that it wouldn't be), MeGUI might resize it to 768x576 or some other 4:3 dimensions (depending on settings). If you set the "Force Input DAR" option to 16:9, MeGUI would resize to 16:9 dimensions instead because you've told it the Input DAR should be 16:9 rather than 4:3, but in both cases it'll assume it's resizing to square pixel dimensions and set a pixel aspect ratio (SAR) of 1:1 (assuming anamorphic encoding is not enabled).

Probably the main usage for the Input DAR option would be to choose between a generic Input DAR and an ITU Input DAR for DVDs. MeGUI defaults to one or the other, depending on the setting in it's options. If the ITU setting is unchecked, it'll default to either an exact 16:9 or 4:3 Input DAR, and if you don't crop it'll resize to 4:3 or 16:9 dimensions, such as 640x480 for a 4:3 DVD. If you change the Input DAR option to the appropriate ITU 4:3, it might resize to 656x480 instead, as the ITU DVD aspect ratio is slightly wider than 4:3. Once again though, MeGUI will set a SAR of 1:1 either way.

As far as I know MeGUI always sets a SAR of 1:1 unless anamorphic encoding is enabled. I don't know what the OneClick "keep input resolution" option does as I don't use the OneClick encoder. Obviously it disables cropping and resizing but whether it forces MeGUI to enable anamorphic encoding or just assume the source has square pixels (it's not anamorphic), I'm not sure.

Setting a SAR yourself in the encoder configuration will over-ride the SAR MeGUI would otherwise set, but if you're always resizing to square pixel dimensions setting -sar 1:1 shouldn't make any difference. Either way though, the SAR being used should be specified in the log file under "standard error stream" for the encoder. The following was a 16:9 DVD cropped and resized to 704x396:

[Information] [30/03/18 1:12:58 PM] Standard error stream
-[Information] [30/03/18 1:13:09 PM] avs [info]: 704x396p 1:1 @ 25/1 fps (cfr)
-[Information] [30/03/18 1:13:09 PM] x264 [info]: using SAR=1/1

From memory, if you set a SAR and it differs from the SAR MeGUI would've otherwise used, there's a line somewhere in the log file along the lines of "forcing -SAR 1:1" (or whatever SAR you set in the encoder configuration).