720p not drop frame?

[Gary Adcock]

[doka15] “I just got my crossgrade for FCP today and was looking through the ‘HD and Broadcast’ page 42 in the ‘Important’ and it says that shooting in 720p format that it is a non-drop frame format. “

24p in all formats is NonDrop, not just 720, but 1080 and SD are all non drop in 24.

[doka15] “So if I shoot 24p it is 24p and not 23.976, is this right?”

NO, NO, NO, 24p video is 23.98. The HVX 200 only has the ability to shoot at 24.0 fps with the EU version of the camera (and the camera needs the ability to be set to 60 hrz , not 59.94)

24p content in video is considered / expected @ 23.98 so that it can directly downconvert to 29.97,
24.0 content needs custom conversion tools not found in most suites to make the video playable in NTSC at 29.97

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows

[Lars Wikstrom]

Well the Kona cards do a 3:2 pulldown on the fly for SD 24p but I am not sure about HD. So our HVX’s shoots 23.976 or 24p video for the American version?

So if it is shooting 23.976 then why does the info say for FCP say that it is non-drop when it clearly is a drop frame at 23.976.

-Lars

[Frank Nolan]

[doka15] “So if it is shooting 23.976 then why does the info say for FCP say that it is non-drop when it clearly is a drop frame at 23.976.”

Because it is a NON drop frame TC. You are thinking about this all wrong. Just because the video time format has a slower frame rate i.e. 29.97, 23.98, 59.94 as compared to whole numbers like 24, 30, 60 does not mean it is drop frame. For instance in 29.97 ntsc video, you can have drop frame or non drop frame TC. Video in NTSC always runs .1% slower than the whole number frame rate. But that doesn’t automatically make it drop frame.

[Lars Wikstrom]

I see what you are saying. So if one wanted to they could mix SD 29.97 and HD 30p which is 29.97 and it works find.

Does the HVX do whole number as well as ntsc standard?

-Lars

[Frank Nolan]

[doka15] “I see what you are saying. So if one wanted to they could mix SD 29.97 and HD 30p which is 29.97 and it works find.
Yes but in FCP you would have to render one or the other to work together on the timeline (up rez SD or down rez HD)

Does the HVX do whole number as well as ntsc standard? “
Although the frame rates on the HVX are listed as 24, 30, 60, the actual FPS are 23.976, 29.97, 59.94. Some of those can be selected as DF or NDF.
Any 24p mode (1080 or 720) will always be NDF. Any 720 modes (apart from 720/30pn) will always be NDF. 30pn can be NDF or DF.
In 480i, 60i and 30p can be selected. 24p and 24pa are always NDF.
I figure the reasoning behind 24p always being NDF is that DF TC was invented so a show of 1:00:00;00 hour could fit into wall clock time for broadcast purposes. Being that all NTSC TV is broadcast at 59.94 interlaced fields per second (labled as 29.97fps) there is no reason to have 23.98 DF TC.

[Lars Wikstrom]

Wow you said a mouth full on that one. I didn’t know that the HVX was that complicated.

—–>I know that the Drop frame started when color signal was introduced. I found this article that talks about how drop frame started..Drop frame timecode dates to a compromise invented when color NTSC video was invented. Basically, the NTSC re-designers wanted to retain compatibility with existing monochrome TVs. Unfortunately, the 3.58 MHz (actually 315/88 MHz = 3579545.45 Hz) color subcarrier would absorb common-phase noise from the harmonics of the line scan frequency. Rather than adjust the audio or chroma subcarriers, they adjusted everything else, including the frame rate, which was set to 30/1.001 Hz.

This meant that an “hour of timecode” at a nominal frame rate of 30 frame/s was longer than an hour of wall-clock time by 3.59 seconds, leading to an error of almost a minute and a half over a day. This caused people to make unnecessary mistakes in the studio.

To correct this, drop frame SMPTE timecode drops frame numbers 0 and 1 of the first second of every minute, and includes them when the number of minutes is divisible by ten. This almost perfectly compensates for the difference in rate, leaving a residual timing error of roughly 86.4 milliseconds per day, an error of only 1.0 ppm. Note: only timecode frame numbers are dropped. Video frames continue in sequence. i.e. – Drop frame TC drops two frames every minute, except every tenth minute.

Drop-frame timecode is used only in systems running at a frame rate of 30/1.001 Hz.<------

[Gary Adcock]

[Frank Nolan] “Any 720 modes (apart from 720/30pn) will always be NDF. 30pn can be NDF or DF.”

Not exactly correct.
Frame Rates below 30hrz are only NDF
Frame Rates at 30hrz or above can be either drop or non drop.

720p60 (as 60hrz or as 59.94hrz) can be drop or non drop.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows

[Frank Nolan]

[gary adcock] “Not exactly correct.
Frame Rates below 30hrz are only NDF
Frame Rates at 30hrz or above can be either drop or non drop.

720p60 (as 60hrz or as 59.94hrz) can be drop or non drop. “

My Bad, you are correct!

[Gary Adcock]

happens to all of us…

I find that often my hands type something that was not in my head.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows