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Level 1

45 points

60p vs 60i video quality

Sorry for asking a very common question but every thread I've searched tends to go down a tangent that doesn't quite answer my question.

I have a Panasonic camcorder that records in 1080 60p or 60i.

My question is video quality. Even though all my output is going to be turned into 30 fps for Apple TV viewing or 30i for YouTube distribution, is my video quality going to be higher, shooting in 60p with a data rate of 34 MB/s vs 60i at 17 MB/s whether the subject is fast moving or not. My thought is to shoot in 60p at the higher data rate even though it will be converted to 30 fps and possible even interlaced for youtube, due to I am dealing with full frames, not interlaced frames and at a higher data rate. Is my logic correct?

I know the file size is doubled shooting in 60p vs 60i, but if the video quality is higher, then I am willing to make that sacrafic.

I guess a follow up question would be, how does FCP convert 60p video into 30i video.

Thanks for your help.

Posted on Jan 25, 2013 5:18 PM

33 replies

A.Y.

Level 1

63 points

Jan 29, 2013 11:44 AM in response to Joe Herth

Joe,

1080 60i = 60 1920X540 interlaced fields per second recorded/interlaced onto 30 1920x1080 frames per second. Since two 1920x540 fields taken 1/60th of a second apart are recorded/interlaced onto one 1920x1080 frame, there will only be 30 1920x1080 frames per second.

Since field 1 contains only the odd lines (upper field) from the first image this is why it only has 1920x540 resolution and field 2 taken 1/60th of a second later contains only the even lines (lower field) from the second image and both fields are recorded/combined/interlaced onto one 1920x1080 frame.

How interlacing works: http://www.neuron2.net/LVG/interlacing.html

You can see progressive is way better than interlace. A Mac with an i3 and better processor will have no problem playing back 1080 60p videos smoothly. For older machines, it's easy to downsize the 1080 60p videos to 1080 30p, 720 60p, or 720 30p with NLE, but archive the 60p AVCHD source for future use.

Uploading 1080p videos to YouTube, the site will automatically prepare 1080p, 720p, 480p, 360p, and 240p resolutions so people with older computers can easily choose a resolution appropriate for their machines. Since YouTube doesn't support 1080 60p yet, just convert 60p to 30p and upload.

A.Y.

Level 1

63 points

Jan 29, 2013 1:03 PM in response to A.Y.

Just want to add: If the 1080 60p video is short and file size manageable, I just upload the 1080 60p movie to YouTube and the site will covert it to the resolutions it currently supports.

Joe Herth Author

Level 1

45 points

Jan 29, 2013 1:11 PM in response to A.Y.

Thanks A.Y.

I'm starting to get my head around it. Thanks for your explaination on interlace. One more question on interlaced video in FCP. If I create a 30p sequence in FC and bring a 60i clip in, does FC take the two 60i fields (odd and Even) to create one frame? If so, is it best to shoot 60p due to the camera shoots one shot to make one frame, vs. taking two fields that were shot 1/60 of a second apart to make one frame? Therefore the 60p footage should be sharper per frame?

Tom Wolsky

Level 10

151,064 points

Jan 29, 2013 1:24 PM in response to Joe Herth

If you shoot 60p and put it in a 30p project FCP dumps everything other frame. It can create a slightly stuttering look because individual frames don't have the right amount of motion blur.

Joe Herth Author

Level 1

45 points

Jan 29, 2013 1:27 PM in response to Tom Wolsky

That make since Tom. But what does FCP do with 60i clips on a 30p sequence? Does it combine the 2 60i fields to make one frame?

A.Y.

Level 1

63 points

Jan 29, 2013 2:01 PM in response to Tom Wolsky

Newer AVCHD2 cameras support using 1/60sec shutter for 60p videos so the amount of motion blur will be the same as 30p videos shot with 1/60sec shutter - the industry standard.

Tom Wolsky

Level 10

151,064 points

Jan 29, 2013 2:05 PM in response to Joe Herth

It tries to blend the fields together. It works with a lot of material. With a lot of fast motion it doesn't look great.

Tom Wolsky

Level 10

151,064 points

Jan 29, 2013 2:05 PM in response to A.Y.

If only users would do that.

Joe Herth Author

Level 1

45 points

Jan 29, 2013 2:31 PM in response to Tom Wolsky

So when you shoot 60i footage (which is 60 fields per second), and bring it into FCP, it creates a 29.97 interlaced sequence. I'm assuming FCP is using all 60 fields in that 29.97 frame sequence. So when I look at one frame in the viewer, I'm only seeing on of the fields due to I see the interlacing at 100% magnification. BUT, in that 29.97 sequence, all 60 fields are present. Is that correct?

And when you output to say a mov file or m4v file, all 60 fields are used to create the file (video). Where if you bring the 60i clip into a 30p sequence, it combines the two fields into one frame. Therefore when the 30p footage is of a fast moving object, your saying it doesn't look as good due to it doesn't have the interlacing working for it anymore. Is that correct?

Tom Wolsky

Level 10

151,064 points

Jan 29, 2013 2:37 PM in response to Joe Herth

What application are you using Joe? In the viewer set the appearance to show both fields.

Therefore when the 30p footage is of a fast moving object, your saying it doesn't look as good due to it doesn't have the interlacing working for it anymore. Is that correct?

Basically. It varies. It depends on the content and the format and the camera and all the factoprs that go into compression. There is absolute on how well it will work. It's very much dependent on the content and camera. Low light with a lot of noise in the image, the field blending can look much worse and appear as pixelzation. High resolution, well lit, well comrpessed, not too much motion, and it'll look fine.

Joe Herth Author

Level 1

45 points

Jan 29, 2013 3:02 PM in response to Tom Wolsky

I'm using FCP7. I'm not sure how to set the viewer to show both fields.

Tom Wolsky

Level 10

151,064 points

Jan 29, 2013 3:13 PM in response to Joe Herth

That's what I thought might be case. This is the FCPX forum. Some of what's in this thread (including what I wrote) doesn't apply to your product. You should address this on the Final Cut Studio forum.

Joe Herth Author

Level 1

45 points

Jan 29, 2013 3:25 PM in response to Tom Wolsky

Yeah, I just realized that when you asked what app I'm using. 😊(blush) Sorry about that. I'll soon be going to FCPX but need to upgrade the computer first. I guess that's why I was in the FCPX forum.

I think I might have 'most' of my head rapped around the interlaced / progressive topic. I DO appreciate the time.

Again, sorry for starting the question in the wrong forum.

A.Y.

Level 1

63 points

Feb 11, 2013 1:44 PM in response to Joe Herth

Joe,

I finally got around to create some samples to show the downside of shooting 60i when your camcorder can shoot 1080 60p.

Deinterlacing will never produce the same image quality or smoothness as shooting progressive at the first place.

When a 1080 60i clip is added to the timeline and then "Shared" (exported), FCPX will default output a 1080 30p .mov (or .mp4) video like this:

The upper 1920x540 field is used and the lower 1920X540 field is discarded, losing half the resolution and 30p will never be as smooth as 60i or 60p. The lines of the upper field are doubled to fill in the gaps, resulting in heavy aliasing around the edges. The results are acceptable but will never be as good as shooting 1080 60p.

A.Y.

Level 1

63 points

Feb 12, 2013 8:56 AM in response to A.Y.

Correction: "WITH THE PROJECT PROPERTIES CUSTOM SET TO 1080 30P" and a 1080 60i clip is added to the timeline and "Shared", FCPX will output a 1080 30p .mov (or .mp4) video like this:

60p vs 60i video quality