[Openexr-devel] New framesPerSecond Attribute?

[Florian Kainz]

I would like propose a new "framesPerSecond" standard attribute
for OpenEXR:

The attribute defines the frame rate at which an OpenEXR image
sequence should be played back.  All frames in a sequence should
have this attribute, and the attribute's value should be the same
for all frames.  If no frame rate is specified for a sequence,
then playback software should assume 24 frames per second.

The attribute's value could be represented either as a floating-
point number or as the quotient of two integers.  A floating-point
number would be easier to use, but it cannot represent NTSC frame
and field rates exactly.  A quotient would be slightly less
convenient, but all commonly used frame rates, including NTSC,
can be represented exactly.

    frame rate                  float           quotient
    --------------------------------------------------------

    35-mm film                  24.0            24 / 1

    PAL video,                  25.0            25 / 1
    50 Hz HDTV frames

    NTSC frames                 29.97003        30000 / 1001

    60 Hz HDTV frames           30.0            30 / 1

    50 Hz HDTV fields           50.0            50 / 1

    NTSC fields                 59.94006        60000 / 1001

    60 Hz HDTV fields,          60.0            60 / 1
    Showscan


If you have comments or opinions, I'd like to hear them.

Thank you,

Florian