1 2 3 Previous Next 33 Replies Latest reply: Feb 12, 2013 1:00 PM by Joe Herth Go to original post
  • 15. Re: 60p vs 60i video quality
    Joe Herth Level 1 Level 1 (40 points)

    First of all, I feel honored to get such expert advise from people I've grown to look up to.  Thank you.

    Karsten, I liked your article.  It made a lot of since.

     

    Some thoughts:

     

    1. Sounds like a lot of advise is to output in 720p30. 

    Since my camera only shoots in 1080 60i or 60p, and not in 720p30, am I getting a similar effect shooting in 60i and bringing it into FC on a 29.97 timeline?  Doing that, the FC sequence looks like it is interlaced.  Even though the preview does not. (Since the field dominance shows top(odd)), Do I need to specify a progressive sequence? I'm assuming 60i is not the same as 30p.  If not, what is FC doing with the extra 30 frames?

     

    2. Tom, thanks for your comment on data rate.  Makes since that progressive requires double the data rate to achieve the same quality as interlaced.  Not sure if this is correct but it almost appears that data rate and files size is somewhat linear.  Somewhat.  Double the data rate and the file size doubles.

     

    3. What is the advantage of shooting or outputting in 720 vs. 1080?  Is it due to, it requires almost half the data rate (file size) as 1080 for a similar quality?  and playing 720 vs 1080 is less taxing on the viewers computer or devise?  and is this due to a smaller data rate needed?

    If the above is correct, is your advise still the same if my camera only shoots in 1080. 

     

    Am I starting to make since or am I still looking through muddy glasses? 

  • 16. Re: 60p vs 60i video quality
    A.Y. Level 1 Level 1 (55 points)

    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.

  • 17. Re: 60p vs 60i video quality
    A.Y. Level 1 Level 1 (55 points)

    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.

  • 18. Re: 60p vs 60i video quality
    Joe Herth Level 1 Level 1 (40 points)

    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?

  • 19. Re: 60p vs 60i video quality
    Tom Wolsky Level 10 Level 10 (106,175 points)

    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.

  • 20. Re: 60p vs 60i video quality
    Joe Herth Level 1 Level 1 (40 points)

    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?

  • 21. Re: 60p vs 60i video quality
    A.Y. Level 1 Level 1 (55 points)

    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.

  • 22. Re: 60p vs 60i video quality
    Tom Wolsky Level 10 Level 10 (106,175 points)

    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.

  • 23. Re: 60p vs 60i video quality
    Tom Wolsky Level 10 Level 10 (106,175 points)

    If only users would do that.

  • 24. Re: 60p vs 60i video quality
    Joe Herth Level 1 Level 1 (40 points)

    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?

  • 25. Re: 60p vs 60i video quality
    Tom Wolsky Level 10 Level 10 (106,175 points)

    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.

  • 26. Re: 60p vs 60i video quality
    Joe Herth Level 1 Level 1 (40 points)

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

  • 27. Re: 60p vs 60i video quality
    Tom Wolsky Level 10 Level 10 (106,175 points)

    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.

  • 28. Re: 60p vs 60i video quality
    Joe Herth Level 1 Level 1 (40 points)

    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.

  • 29. Re: 60p vs 60i video quality
    A.Y. Level 1 Level 1 (55 points)

    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:

     

    60i.jpg

     

    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.