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 2024-11-21 09:11 / Tags: Photo. / link

Three steps to a basic IPsec tunnel

Sometimes, the solution is so simple that you miss the wood for the trees.

1. Install StrongSWAN on both sides.

2. Edit /etc/ipsec.conf on each side:

conn foo
        left=fd00::31:1
        right=fd00::32:2
        auto=start
        authby=psk

3. Edit the ipsec.secrets on each side.

fd00::31:1 fd00::32:2: PSK "our happy shared key"

Certificate-based

Generate a certificate plus key for both left and right side (give them appropriate names, left/right is just a filler here):

openssl req -x509 -nodes -key /etc/ipsec.d/certs/leftside.pem -keyout /etc/ipsec.d/private/leftside.pem.key

This is just a self-signed certificate, but should fit the bill for "simple". Each side needs to have their own certificate and key, plus the right side's certificate. (The left side needs to have leftside.pem, leftside.pem.key, and rightside.pem, the right side needs to have rightside.pem, rightside.pem.key and leftside.pem.)

/etc/ipsec.conf for the left side:

conn foo
        left=1.1.1.1
        right=2.2.2.2
        auto=start
        keyexchange=ikev2
        leftcert="/etc/ipsec.d/certs/leftside.pem"
        rightcert="/etc/ipsec.d/certs/rightside.pem"

/etc/ipsec.secrets for the left side:

1.1.1.1 2.2.2.2 : RSA "leftside.pem.key"

Right side should be obviously mirrored. You can also use the %any variant in ipsec.secrets, if needed.

Posted 2008-02-24 07:02 / Tags: Ipsec, Linux. / link