When is 25p not 25p - maybe?

[virgil21]

Despite not wishing to continue this “discussion”, I think it only proper that I thank you for your patient and clear reply. So it is not a flag but a real change of output signal. I appreciate your help. When I make a test export, Edius file properties shows 25fps Upper Field. I haven’t got anything external that shows me the field order. MediaInfo just shows 25fps. With thanks.

I did finally find some information in KYNO. It shows the properties of the test file exported from Edius as being:
Frame rate: 50i
Scan type: “Interlaced tff”
It doesn’t use the term PsF in its file properties window.
MYNC doesn’t bother with that level of detail.

[BernH]

I did finally find some information in KYNO. It shows the properties of the test file exported from Edius as being:
Frame rate: 50i
Scan type: “Interlaced tff”
It doesn’t use the term PsF in its file properties window.
MYNC doesn’t bother with that level of detail.

That’s because PsF is a signal designation for transmitting a progressive image in an interlaced infrastructure, not a file framerate designation. PsF is an interlaced signal, but an interlaced signal is not necessarily PsF unless there is no temporal difference in the fields.

[Ron Evans]

Normally PAL interlace is upper field first NTSC Lower Field First. To me confusion arose when the system changed from calling interlaced 50i and 60i to 25fps and 29.97fps ( the time code for the video aligned with the interlace sync pulse every two fields) One must pay real attention to whether it is 25P or 25fps or 29.97fps or 29.97P. Very different. PsF is constructed by the system taking 24P, 25P or 29.97P and extracting an upper field from the frame , placing in a field then a lower field from the same frame placing in the next field. So that rather than a normal interlaced video stream having a real time difference between fields for PsF there is none. Field pairs are from the same progressive frame. The playback system recognizes this and plays a progressive output.

If the file says fps and does NOT say progressive it is interlaced.

[virgil21]

Alice in wonderland?

As the man said:

“Why, sometimes I've believed as many as six impossible things before breakfast”.