Converting 23.98 times to 29.97i

Didn't know if this would be of any use; but I thought it might help someone.

I had a 23.98 (DVCPRO) timeline that needed to be timed to a TRT: 28:30 mins.; then delivered in a 29.97i format.
The following are the times I used to get the 24p to come out to the right times after transcoding.


Timing When Transcoding for Broadcast

23.98 fps NDF (Progessive)
00:59:00:00 Sequence Start

00:59:00:00 Bars and Tone (Duration 00:00:30:00)
00:59:30:00 Black (Duration 00:00:09:22)
00:59:39:23 Slate (Duration 00:00:18:00)
00:59:57:23 Black (Duration 00:00:02:00)

00:59:59:23 Program Start (Duration 00:28:28:07, make last frame 01:28:28:05 black)

01:28:28:06 Black (Duration 00:00:10:00, Last Frame 01:28:38:05)
01:28:38:06 Sequence Last Frame

The above 23.98 fps times, will transcode to the following times in a 29.97 fps timeline.

29.97 fps DF (Interlaced-Top)
00:59:00:02 Sequence Start (may need to write a new Start Timecode in transcoder)

00:59:00;02 Bars and Tone (Duration 00:00:30:00)
00:59:30;02 Black (Duration 00:00:09:27)
00:59:39;29 Slate (Duration 00:00:18:00)
00:59:57;29 Black (Duration 00:00:02:00)

01:00:00;00 Program Start (Duration 00:28:30;00, last frame 01:28:29;29 black)

01:28:30;00 Black (Duration 00:00:10;00)
01:28:40;02 Sequence Last Frame

Thanks. That's interesting. But isn't 23.976 in NDF so it doesn't synchronize to a real work clock? So why is the duration off when it converts to 29.97 NDF?



www.strypesinpost.com

I've updated the post a few times. I think it is right now. Also tried to clarify by writing the description a little differently.
But, it does work this way.

I didn't realize that the 23.976 was a NDF format; but the end result needed was DF for broadcast—That is why it starts at 00:59:00:02.
If by "real work clock" you mean actual time, it does come out to the right durations—TRT 28:30, etc. That was why I tried to map it all out. I wanted the durations right, and I wanted the program to start at 01:00:00;00 and end at 01:28:30;00.

Scotty
Living Waters Publications

[but the end result needed was ND for broadcast—That is why it starts at 00:59:00:02. ]

You mean "DF"-- not "ND" - yes? Non-drop would start on 59:00.

Best, as always,
Loren

Oops, Yes, that's right - DF.

So... let me ask you guys, even though the time code shows 28:30, is that from a realtime basis, or at least from a broadcast eng's perspective? How would I make a realtime determination? Is it necessary?

Thanks.

What format is the timecode that is giving you the 28:30?

If it's anything other than 29.97 drop frame TC, it's not going to be an accurate representation of time from a TV perspective.

And yes, the real duration or "clock time" is important to broadcasters and to you.
You would risk the time being out by roughly two seconds. Spread out over three segments that could lead to bumpers being cut off and other general unpleasantness.

ak
Sleeplings, AWAKE!

Either use a timecode calculator...or here's my trick

[lfhd.net]

The Timecode Calculator I have on my iPhone shows that 28:30 NDF equals 28:31:22 in DF timecode.

So if you want your show to time out to 28:30;00 DF...your NDF timing needs to be 28:28:06 NDF

Test this with my SLUG method.


www.shanerosseditor.com

Listen to THE EDIT BAY Podcast on iTunes
[itunes.apple.com]

Hi Ross and Shane,

Yes, 29.97 DF is what I'm delivering. So I gather from what you are saying that what I am ending up with is valid for broadcast and represents realtime, that will work then.

Thanks.

Hey Shane,

Just read your article. Thanks for the Workflow.

Interestingly, after much struggle and back and forth with my project, I thought, why don't I make a 29.97 timeline and see how it comes out. Then after struggling with that for a while I thought, why don't I just use a slug for time? Long story short, wish I had read your article first. Now that I have, I have some insight to; "The Rest of the Story"

Good stuff. Thanks

Shane, bet that workflow would be different if you're cutting on the Avid.



www.strypesinpost.com

Hee...righto! This workflow is not needed on the Avid, as it has the option to show you both the NDF timing, and the DF timing. Built in.

LOVE that.

It also mixes 23.98 and 29.97 and 59.94 very well. It does a lot more than FCP 7 can...for sure.


www.shanerosseditor.com

Listen to THE EDIT BAY Podcast on iTunes
[itunes.apple.com]