Going crazy - please stop my brain imploding (aspect ratio issue)

Discussion in 'Digital Video' started by Floop, Mar 9, 2011.

  1. Floop macrumors regular

    Jan 14, 2003

    I have an MP4 video file which was filmed on a Samsung SMX-F33BP digital camcorder.

    The camcorder was set to film in 16:9 Wide and when the footage is played back on the camcorder itself, the 16:9 aspect ratio is used and works fine.

    However, in my iMac the MP4 file shows has having dimensions of 720 x 576 (in H264 codec). This is a 4:3 ratio and it plays in a 4:3 squished aspect ratio in Finder's Quick Look, also in Quicktime Player, also in VLC, and also when imported into iMovie 11 it imports it in a 4:3 ratio.

    Now, I have figured that if I load the clip into Quicktime Player Pro 7 and amend the aspect ratio to read 1080 x 576 then the clip looks correct when played in Quicktime Player Pro 7... but unfortunately it is still squished into 4:3 when viewed in Quicktime X, and when imported into iMovie 11.

    I need a simple solution here, because this is for use in a school and the staff member who will do the video editing won't cope with anything too complex.

    I simply cannot see why this is happening, and it is driving me nuts!

    The camera filmed it as 16:9 widescreen, but the MP4 dimensions are 4:3... how can I solve this!?

    Many thanks

  2. KeithPratt macrumors 6502a

    Mar 6, 2007
    720x576 is the resolution of all PAL video, whether 4:3 or 16:9. If you do a little maths, you'll see it's not actually 4:3, so a Pixel Aspect Ratio is always needed for it to display properly. When it comes to editing, it's up to the editor to specify whether the video should be treated as 4:3 or 16:9.

    I haven't used iMovie since the days of '06, but with that version you'd specify DV or DV Widescreen when starting a new project.
  3. mBox macrumors 68020

    Jun 26, 2002
    I guess the op can just export from MPEG StreamClip as the right aspect to put op at ease? Its freeware :) Make sure you dont change formats though just aspect ratio.
  4. Floop thread starter macrumors regular

    Jan 14, 2003

    Thanks for your help guys.

    It turns out that the Samsung video camera that recorded the video seems to be recording it in 'PAL Widescreen' which is, as has been stated on this thread, just 720x576 but squished outwards using non-square pixels to 'appear' widescreen.

    This is fundamentally different from proper HD widescreen which a different camera I tested records - I tried recording some footage with a Flip HD, and a Sanyo Xacti HD, and both recorded 'true' widescreen that worked properly in the iMac and in iMovie.

    It seems that the Samsung videocamera is to blame, the widescreen is really a bit of a cheaty-faux-widescreen using no more actual pixels than the 4:3 footage, so I'll just have to use a different video camera to get around the problem!

    (Thanks for the tip on MPEG StreamClip but I don't want the staff to have to do an extra step).
  5. mBox macrumors 68020

    Jun 26, 2002
    You dont have to use a diff camera if your output is to DVD. You just have to makes sure you set your projects to 16:9.
    Ive worked with some many faux res in HD/DVD so its not that big of a deal to fix.
    At least you didnt spend 40k on a stupid Sony XDCAM just to find out that its shooting at 1440x1080 which is the same trickery most SD cameras use for capturing 16:9 aka Anamorphic.
  6. Floop thread starter macrumors regular

    Jan 14, 2003

    The output is not to DVD video, they are going to be video files on the network for people to refer to (thanks though for the pointer).

    On a separate tack - I just stumped up cash for Flip4Mac as I wanted to export to WMV via QuickTime in iMovie. I now discover that this is in fact not supported in Flip4Mac. Fantastic! Bah!
  7. mBox macrumors 68020

    Jun 26, 2002
    Im pretty confident you can take your files and have them output to the right size of 16:9.
    Yea we have Flip4Mac, worked for WMV never really used it for anything else.
  8. mBox macrumors 68020

    Jun 26, 2002
    Its freeware? Why not just take the clips and convert to 16:9.
    Since your running it as a doc then you dont to be NTSC Legal.
    Leave it as a PAL file with the right aspect ratio.

Share This Page