Notes on photo sphere/panoramic EXIF metadata
- Google's EXIF/XMP metadata tag specification for panoramic images
- Panorama images with sky are to have a negative value for the CroppedAreaTopPixels tag. (The panoramic viewer of Facebook ignores the value altogether, though, and assumes the horizon in the middle of the picture.)
- If a camera or software normally produces panoramic images with cylindrical projection, then doing a vertical capture actually produces a transverse cylindrical image. There is no standardized value for the EXIF ProjectionType field to cover this. (One option is to reproject them to equirectangular — which, again, is not very well supported.)
- Facebook's document on what tags to set
- The Facebook web interface insists that FullPanoHeightPixels be half the size of FullPanoWidthPixels. Else you get “no new photos were uploaded”.
Posted 2024-10-14 11:10 / Tags: Photo. / link
The perfect Sun disklabel?
Disk /dev/sda (Sun disk label): 19 heads, 248 sectors, 7508 cylinders
Units = cylinders of 4712 * 512 bytes
Device Flag Start End Blocks Id System
/dev/sda1 u 0 7508 17688848 5 Whole disk
/dev/sda2 1 29 65968 83 Linux native
/dev/sda3 u 0 7508 17688848 5 Whole disk
/dev/sda4 30 58 65968 82 Linux swap
/dev/sda5 59 7508 17549844 83 Linux native
Explanation:
1. The first partition needs to start at cylinder 0.
This is required for OpenBoot automatic booting. (You could otherwise boot
by specifying a partition, e.g. boot disk0:c
.) The
/boot
fs could also start at cyl 0 iff cylinder 0 is
never touched (as is the case with ext2 and ufs) -- would not be the case
with e.g. xfs. There is no other requirement, so I just made it a dummy
partition marked as "Whole disk".
2. The /boot partition needs to be ext2, ext3, romfs or ufs, because that's the only thing SILO currently supports. There is no real reason it starts at cylinder 1, it could be anywhere. (Once upon a time, x86 BIOSes could only read from the first 1024 cylinders. But since this is neither x86 nor an old BIOS, so that's that.)
3. For compatibility reasons, I heard, the third partition should be "Whole disk".
4. The swap partition, if any, should be at the start (or near the beginning) of the disk because read speeds are higher there.
5. Finally the base filesystem.
Posted 2006-03-30 10:03 / Tags: / link