Vintage Erotica Forums - View Single Post - [Guide] Aspect Ratio

**J4ZZ** · September 7th, 2014, 05:37 PM

This is called "Anamorphic Encoding" where the encoded aspect ratio (AR) of a movie is different from the displayed aspect ratio.

You can set this information in mkv, mp4 and technically even in avi files.

So, what is it exactly.

Well, basically it's simply putting the Display Aspect Ratio information into the video file like it's done on a DVD (store in one aspect and display in another).

There are two prefered methods to choose from. Strict and Loose anamorphic

Strict anamorphic concentrates only on one thing: preserving the exact visible frame of a DVD, displayed to exactly the same size as it would be from the DVD.
This means it will sometimes use odd dimensions, ones that don't divide cleanly by 16. When this happens, the video encoders cannot work as efficiently — x264 warns that "compression will suffer."
It also means that, when using strict anamorphic, it is impossible to change the stored size of the encoded frame. It will simply use the exact frame size of the DVD and apply cropping.

Loose anamorphic starts off the same way as strict -- with the exact visible frame on the DVD. But then it adjusts the dimensions to be sure they divide cleanly by 16. After that, it adjusts the display size so the film's aspect ratio is preserved with the new dimensions.

MeGui, Handbrake, Vidcoder and many others are capable to add this information when encoding.

If you need to change AR in existing mp4 or mkv files without re-encoding you could use mp4box (yamb is the gui) or MKVmerge (part of the MKVToolnix package). For avi files there is MPEG4 Modifier for getting the job done.

Regards,

J4ZZ

September 7th, 2014, 05:37 PM	#4
J4ZZ Vintage Member Join Date: Aug 2005 Posts: 1,092 Thanks: 34,238 Thanked 29,929 Times in 1,034 Posts	This is called "Anamorphic Encoding" where the encoded aspect ratio (AR) of a movie is different from the displayed aspect ratio. You can set this information in mkv, mp4 and technically even in avi files. So, what is it exactly. Well, basically it's simply putting the Display Aspect Ratio information into the video file like it's done on a DVD (store in one aspect and display in another). There are two prefered methods to choose from. Strict and Loose anamorphic Strict anamorphic concentrates only on one thing: preserving the exact visible frame of a DVD, displayed to exactly the same size as it would be from the DVD. This means it will sometimes use odd dimensions, ones that don't divide cleanly by 16. When this happens, the video encoders cannot work as efficiently — x264 warns that "compression will suffer." It also means that, when using strict anamorphic, it is impossible to change the stored size of the encoded frame. It will simply use the exact frame size of the DVD and apply cropping. Loose anamorphic starts off the same way as strict -- with the exact visible frame on the DVD. But then it adjusts the dimensions to be sure they divide cleanly by 16. After that, it adjusts the display size so the film's aspect ratio is preserved with the new dimensions. MeGui, Handbrake, Vidcoder and many others are capable to add this information when encoding. If you need to change AR in existing mp4 or mkv files without re-encoding you could use mp4box (yamb is the gui) or MKVmerge (part of the MKVToolnix package). For avi files there is MPEG4 Modifier for getting the job done. Regards, J4ZZ __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.