Whenever I use this button, the resulting image appears "shorter" in the preview window than the frame it was taken from. It has a black band at the top and bottom. According to Photoshop, the image is 352x240.
If I change my preferences > Edit Tab > Image Resampling Option to "Fit to Project Size" instead of "Keep aspect ratio", I still get a 352x240 image, but without the black bands.
Even after rendering as MPEG-1 or MPEG-2, I see the bands in the "Keep aspect ratio" version of the image, but not in the "fit to project size" version - which tells me the black bands version is in fact a different image and not just a preview window display issue.
[Edit:] Oddly in Photoshop, the images look identical (without the black bands), and the height, width, and resolution list exactly the same. However they still render differently as MPEGs (black bands vs. no black bands)
Why does this happen? Here are the project properties:
NTSC drop frame (29.97 fps)
MPEG files
24 bits, 720 x 480, 29.97 fps
Lower Field First
(DVD-NTSC), 4:3
Video data rate: Variable (Max. 8000 kbps)
LPCM Audio, 48000 Hz, Stereo
"Save as Still Image" Button
Moderator: Ken Berry
I have an idea about what's going on...
Still images use square pixels. Video typically* uses non-square pixels.
A 640x480 still image has a 4x3 ratio, which works-out mathematically for a standard video monitor. But, 352x240 can be used for standard 4x3 video, and rectangular pixels are required to make this work-out mathematically. 720x480 is used for both 4x3 and 16x9 (widescreen) NTSC DVDs.
When you convert your 352x240 video to a still without resampling, the ratio is distorted when the pixels are displayed as squares.
* Computers can play video with square pixels, and I believe the Video iPod uses a square-pixel format by default.
Still images use square pixels. Video typically* uses non-square pixels.
A 640x480 still image has a 4x3 ratio, which works-out mathematically for a standard video monitor. But, 352x240 can be used for standard 4x3 video, and rectangular pixels are required to make this work-out mathematically. 720x480 is used for both 4x3 and 16x9 (widescreen) NTSC DVDs.
When you convert your 352x240 video to a still without resampling, the ratio is distorted when the pixels are displayed as squares.
* Computers can play video with square pixels, and I believe the Video iPod uses a square-pixel format by default.
[size=92][i]Head over heels,
No time to think.
It's like the whole world's
Out of... sync.[/i]
- Head Over Heels, The Go-Gos.[/size]
No time to think.
It's like the whole world's
Out of... sync.[/i]
- Head Over Heels, The Go-Gos.[/size]
-
Trevor Andrew