[opendtv] Re: Frames Per Second of 720P

  • From: Tom Barry <trbarry@xxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Fri, 18 Jul 2008 19:58:31 -0400

It has been my experience that 1080i proponents like to call it 1080i/60 and progressive fans like to call it 1080i/30.


I have moved from the first to second camp over the years but still can't get very excited about it.

- Tom

Hoffmann, Hans wrote:
John,

This kind of confusion is why the EBU has decided for a different
nomenclature
Active_lines    scanning / frame rate
1080                    i          / 25
720               p        / 50

The small "i" characterises whether it is an interlaced format which means
each frame is divided into 2 fields. But I understand that marketing people
don't like smaller numbers if they compare format;-)

Regards,
Hans
-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-
bounce@xxxxxxxxxxxxx] On Behalf Of John Shutt
Sent: 18 July 2008 14:37
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: Frames Per Second of 720P

The Sony brochure
http://bssc.sel.sony.com/Professional/docs/brochures/mvs8000.pdf states
that
the switcher operates at 1080i60, 1080i59.94, and 1080i50.  This is
probably
where the Sony rep got confused, because 1080i60 is indeed 30 unique
frames
per second, and 1080i59.94 averages out to 29.97 unique frames per
second.

This is exactly why I don't understand the nomenclature that seemed to
only
come into fashion with the advent of HD, of calling 1920x1080 thirty
frames
per second interlaced as "i60"  Read the timecode, there are 30 frames
per
second in the timecode, therefore it is a thirty frames per second
(ignoring
the 1.001 for the moment) format, and should be called "i30" which
clearly
states 30 fps, presented interlaced.

When recording "1080i59.94", you can frame advance through the timecode
and
watch the time change from 00:00:03:29 to 00:00:04:00.  In contrast,
with
720p59.94, you can watch the timecode change from 00:00:03:59 to
00:00:04:00.

"1080i60" looks better on paper next to "720p60" I suppose.

John

----- Original Message -----
From: <dan.grimes@xxxxxxxx>


I just attended a demonstration of a Sony MVS8000 production switcher.
The
switcher can output 720 at 59.94 P and 1080 at 29.97 I.

As I we discussed frame stores, I asked if it took 60 frames to store
a
one second motion clip (120 with a key) and they said no, only 30.
They
(multiple Sony reps) were telling me all video is 30 frames per
second, no
matter what the format.




----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:

- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org

- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.



-----------------------------------------
**************************************************
This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error, please notify the system manager. This footnote also confirms that this email message has been swept by the mailgateway
**************************************************

----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:

- Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word 
unsubscribe in the subject line.



--
Tom Barry                  trbarry@xxxxxxxxxxx  



----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:

- Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word 
unsubscribe in the subject line.

Other related posts: