Conversion of DVD's to mp4 or mkv and using Anamorphic settings in Vidcoder

vbimport

#1

One of the more difficult things to understand in conversion of DVDs to mp4 or mkv is the use of anamorphic encoding that is found in DVD-video.

DVD-video stores the video in standard resolutions, and there are only certain sizes that are accepted. The resolutions normally seen in commercially made DVD’s are 720 x 480 (NTSC) or 720 x 576 (PAL). You’ll see that the ratios for these resolutions are 1.5:1 and 1.25:1. But movies are not filmed in these ratios. Widescreen movies are made in many different ratios, including 1.78:1 (16 x 9), 2.35:1, 1.85:1, etc. See this explanation at Wikipedia.

The actual display from a widescreen anamorphic DVD is therefore not 720 x 480 or 720 x 576…your player will output in a wider view…the display resolution.

So when converting to mkv or mp4, you have to make a decision on how to deal with this. It is possible to use anamorphic settings in a program like Vidcoder, but there is no guarantee that your equipment will be able to recognize this format. So many use square pixel output instead.

While reading at Videohelp, I came across an explanation that I like, from a member there named hello_hello. http://forum.videohelp.com/threads/361709-RIP-and-Convert-to-720x756?p=2295816&viewfull=1#post2295816


#2

The discussion at Videohelp doesn’t mention the Loose Anamorphic setting in Handbrake or Vidcoder. But this generally starts off the same as the Strict setting, but insures that every value is a multiple of 16.

For a better explanation, look at the Anamorphic Guide for Handbrake: https://trac.handbrake.fr/wiki/AnamorphicGuide


#3

The examples in the Videohelp thread were taken from a 16:9 PAL dvd.

Here are some from a widescreen NTSC DVD. The first shows Strict Anamorphic with no cropping:

You can see that the mkv file is set to be encoded in the same manner as the DVD. It has the same pixel aspect ratio and storage frame size.



#4

Enabling automatic cropping, to get keep from encoding the black bars on the top and bottom changes the storage and display resolutions rather dramatically:

This particular movie also gets trimmed slightly on width.



#5

Next up we look at it with the Anamorphic setting at None:

You can see two big changes here. First off, you are working with square pixels, instead of anamorphic ones. The pixel aspect ratio is 1:1. And second, your storage resolution has jumped up to match the display resolution.

Adding Automatic cropping gives 840 x 362 final resolution with this particular movie.

But here is a move you don’t want to make. This is the combination of None in Anamorphic and removing the check mark in Keep Aspect ratio.

The storage and display resolutions are the same, but this display resolution won’t look right in playback. You’ve lost the widescreen display.