Resize 1080i30 to 720i or 720p - What is more compressible?

[moviefan]

Hey guys,

I have a 1080i30 source and would like to resize it to 1280x720 for a lower file size. Now I'm asking myself and you what is more compressible: Leaving the video interlaced or deinterlacing it for compression with x264? Maybe the other question is rather a matter of avisynth, but it should be a simple one: If deinterlacing, should I first resize or first deinterlace?

[Egladil]

resizing interlaced material is a no-go, it will break the interlacing and you won't be able to deinterlace it ever again. always deinterlace before resizing. see www.100fps.com for examples of resizing before deinterlacing

[nm]

Resizing interlaced video isn't that bad if you are careful:
http://forum.doom9.org/showthread.php?s=&threadid=74906

As to the question on whether to deinterlace before encoding or not, I'd say that deinterlacing beforehand is a better option if you are willing to go from 30i to 30p. However, if you want to keep all the temporal information (30i to 60p), the choice is more difficult. To make the encode compatible with hardware players, I'd choose between 1080i30 and 720p60. The latter is probably easier to play on various PC systems, since you don't need to deinterlace on playback, but you may lose as much as half the spatial information when scaling down.

[moviefan]

The thing is that I want to stay Blu-ray compliant, so I would probably want to stick to 720p24, but how should I deinterlace the video? It's TFF...

[Atak_Snajpera]

so I would probably want to stick to 720p24
25 and 30 is also supported

[scharfis_brain]

you should always stick to the framerate (29.97fps) or the fieldrate (59.94 fps) of your source.
If you force true interlaced video to 24fps, you'll get jerky motion, because the framerates aren't matching.

[Trahald]

actually 4 blu ray you have 23.976/50/59.94 ... as scharfis said I wouldnt do 23.976... you are forced to 59.94. you can also do 29.97 and add frame doubling (flags) but i dont know if anything supports adding that. it would be a legal stream.

*edit*
those are rates for 720 which is progressive only.

[audyovydeo]

The real question is : what is your final purpose ?

if you want to deinterlace for watching (ie deinterlace > encode > watch) then go ahead with the above advice.

If you want to deinterlace for archiving (ie deinterlace > throw away your interlaced sources, forever), I'd say think twice about it.

cheers
audyovydeo

[moviefan]

Actually, I don't really care about deinterlacing or not deinterlacing, but I want to resize the video to 1280x720 to save space at best quality with least file size. 1920x1080 is for me an overkill since the amount of detail in that isn't worth the disc space required (in my eyes). So most important for me is to resize the video and compress it most efficiently, but I don't know whether compressibility is influenced by the frame type (interlaced or not). If I was to deinterlace the movie, I would probably want to stick to mcbob, but for me it's completely impossible to apply this filter on the 1080i source because it would take forever to deinterlace it. So how do I achieve best compression?

[scharfis_brain]

try yadifmod() with nnedi()