Why inverse telecine or deinterlace?

[Justin832]

I am ripping my entire dvd collection because my toddler destroys discs & bookshelves. I am ripping with MakeMKV and then transcoding to mp4 files with FFmpeg on Linux. My videocodec is h264 and my audio codec is ac3 )which is typically a straight copy of the audio stream).

My main priority is to achieve near perfect quality, my next priority is keeping small file sizes, and I basically do not care about time.

I have been given these two recommendations:

1) If your DVD's are "theatrical", e.g. Hollywood movies, or TV drama series - they should be IVTCed (inverse telecine, to return the original film frames at 23.976FPS instead of interlaced 29.97) before encoding.

2) If they are interlaced (maybe some sports DVD's for example), you should encode interlaced.

Why should I inverse telecine or encode as interlaced? While either of these settings result in a video file that is different from the dvd? If I ignore these two considerations, will I have any quality issues?

Should I ever deinterlace? If so, why? If I ignore deinterlacing, will I have any quality issues?

I do not care to put forth effort on each video to make it better than the dvd.

Thank you for your help.

[manono]

Why should I inverse telecine...

When you see the interlacing when viewing your MP4s, then you'll know why you should IVTC. When they play jerky from being deinterlaced by your player (not as noticeable), then you'll know why. Films on NTSC DVD are encoded as 23.976fps with either hard or soft telecine added to conform to the NTSC DVD standard. When reencoding them you'll want to return them to that original framerate. I have no idea whether or not FFmpeg can IVTC, or can IVTC well.

... or encode as interlaced?

I'm not sure I would, for MP4. I'd probably bob them with a decent bobber. Again, I have no idea whether or not there's a decent bobber available in FFmpeg.

If I ignore deinterlacing, will I have any quality issues?

When you see interlacing when watchiong the videos, then you'll know. Why not test out a few to see?

While either of these settings result in a video file that is different from the dvd?

Of course they will. Even just reencoding the DVDs will leave you with 'a video file that is different from the dvd'.

[El Heggunte]

I am ripping my entire dvd collection

because my toddler destroys discs & bookshelves.

Welcome to my IgnoreList.

[Justin832]

Welcome to my IgnoreList.

I've come across a lot of haughty and crass comments since I started working with open source software - and it has not all been directed at me. I would think this sort of thing would be frowned upon in a community where our collective contributions comprise the foundation of our tools and hobbies.

Maybe someday you'll have something more worthwhile to do than make lists. God speed.