How to make interlaced H.264 export

[Shane Ross]

1. Why?

2. Why?

H.264 is a web delivery codec…unless it is utilized for BluRay. Being a web delivery codec it is a progressive codec, as all computer monitors are progressive monitors…interlacing doesn’t exist in the computer world.

Shane

GETTING ORGANIZED WITH FINAL CUT PRO DVD…don’t miss it.
Read my blog, Little Frog in High Def

[David Roth weiss]

Shane,

Actually, an h.264 from an interlaced source will be interlaced, unless purposefully deinterlaced, if exported at the original pixel dimensions. In fact, a good rule of thumb is that most typically applies is that deinterlacing is required unless an export is set to 50% of the original pixel dimension, at which point the a deinterlace becomes redundant. This is why we do often hear people complain about their exports at “current settings” suddenly showing the interlace in QT Player on their computer monitor, whereas in FCP they didn’t see it.

So, the answer to the original post is that the export, if the original is interlaced, must be at the pixel dimensions of the original, or at least greater than 50% of the pixel dimensions of the original. Ideally, equal to the original would guaranty the best interlaced result. Why he needs it is another question altogether — possibly as a high quality transportable file to someone on Premiere would be my guess…

David

David Roth Weiss
Director/Editor
David Weiss Productions, Inc.
Los Angeles

POST-PRODUCTION WITHOUT THE USUAL INSANITY ™

A forum host of Creative COW’s Apple Final Cut Pro, Business & Marketing, Indie Film & Documentary, and Film History & Appreciations forums.

[Shane Ross]

REALLY?

I’ve gotta stop talking about stuff I really don’t know about (but think I do). I thought I knew about this.

BUT, this is why I am an editor and not an encoder… Why I deliver mainly on tape and not the web.

Shane

GETTING ORGANIZED WITH FINAL CUT PRO DVD…don’t miss it.
Read my blog, Little Frog in High Def

[Jaroslav Klaus]

Thanks David.

The reason for my demand is
1. the final device – player – doesn’t support 1080p50 because of limited performance
2. I need 50fps because of fast movements in the footage (I know 50i is commonly identified as 25fps but I can’t agree with this simplification as each field comes from different frame)

So I have an option to export the footage to 720p50 or 1080i50 and deinterlace it during playback. I believe I’ll get better result with 1080i50 with _proper_ reinterlacing from 1080p50 than with 720p50 with the same bitrate.

I want to use interlace technique to safe 50% of bw with highest quality.

I’ve tried to export 50i to H.264 without scaling. The output looks interlaced but QT X, QT Pro 7 nor VLC can’t deinterlace it properly. I don’t know why.

[Rafael Amador]

Just drop your p50 stuff in a i50 sequence and export as H264.
Rafael
Ps; What yo gonna do with that?

http://www.nagavideo.com

[Rafael Amador]

[Jaroslav Klaus] “I believe I’ll get better result with 1080i50 with _proper_ reinterlacing from 1080p50 than with 720p50 with the same bitrate. “
Not sure. I would make some tests before stating that.
rafael

http://www.nagavideo.com

[Jaroslav Klaus]

Well technically 720p50 should be worse than 1080i50 with the same bw because of two reasons:

1. downscale and backward upscale process by factor 1:2 (1080 to 540) is technically better then by factor 2:3 (1080 to 720) because of interpolation issue (1:2 + 2:1 vs. 2:3 + 3:2)

2. hres is constant for 1080i conversion in contrast to 720p

But I have to agree the technical aspect is one thing and human perception is other thing.

Furthermore the difference is not probably big and because of technical difficulties like proper reinterlacing in H.264 and deinterlacing from this codec I’ll probably stay with 720p.

[Jaroslav Klaus]

I have 50p staff in 50p sequence (I did some editing etc.). Should I export it first and import back as one clip? Or is it possible to link it “somehow” to 50p sequence? I’m not sure but I guess AE does something similar.
Thx

[Rafael Amador]

You may try to Copy& Paste or drag from one sequence to the other.
Not sure what will happens with your animations because the time base are different.
Try, you have nothing to lose
rafael

http://www.nagavideo.com