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23.976 footage converted to 29.97 is lagging from the camera audio

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Sarah Furie
23.976 footage converted to 29.97 is lagging from the camera audio
on May 14, 2016 at 3:12:49 am

I have a project that is 1080p/29.97 and production shot some 23.976 footage so I converted it in Davinci. I made it drop frame 29.97 to match the other footage.

Sometimes when there is a really long clip, the 23.976 footage converted to 29.97 video is lagging from the camera audio. There is no production audio, so that it is not an issue. But apparently the conversion creates a lag. Any way to fix this? Or is this just normal and I have to accept it because I added extra frames to the 23.976 footage?


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John Pale
Re: 23.976 footage converted to 29.97 is lagging from the camera audio
on May 14, 2016 at 11:07:08 pm
Last Edited By John Pale on May 14, 2016 at 11:08:52 pm

That should not happen. Your settings may have been incorrect. Was this double system sound or was the audio recorded in camera?

By the way,... You don not need to convert the footage in Resolve or a third party program. Avid is perfectly capable of adding proper pull down in the timeline.


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Michael Phillips
Re: 23.976 footage converted to 29.97 is lagging from the camera audio
on May 15, 2016 at 2:08:13 am

And only the latest Resolve 12.5 adds the 2:3 pulldown function on output (just tested it and it works fine). But audio shouldn't drift if sources are 23.976 @ 48kHz and 29.97 @ 48kHz. If it looks like a .1% drift which is roughly 1 frame drift every 42 seconds, then perhaps the source was 24 and not 23.976 or one of the files was not what you thought it was?

Also, as John says, Media Composer will add 2:3 on source clips.


Michael


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Sarah Furie
Re: 23.976 footage converted to 29.97 is lagging from the camera audio
on May 15, 2016 at 6:55:00 am

Hey Guys,

The footage was 23.976, not 24, when I bring it in Avid. But, when I tried to group the footage it wouldn't let me so I was told by other assistant editors to bring everything into Avid matching, so I converted the 23.976 NDF footage into 29.97 DF. I don't believe I have a problem on much else, except for long clips, which makes me wonder about the lag. I was told it was best NOT to use the convert tool in Avid. When I did use it, actually, because there were some clips that Davinci didn't work well with, there was some ghosting. :/


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Michael Phillips
Re: 23.976 footage converted to 29.97 is lagging from the camera audio
on May 15, 2016 at 1:31:43 pm

What were the file formats and rates before using Resolve to make the new media? Were you using Resolve 12.5 which has the new feature of adding 2:3? It is in the deliver tab when selecting output rate.

In your scenario, is the material that is drifting, drifting early or late compared to the 29.96fps material?

On a related note, NDF or DF do not affect the playback rate. I would actually recommend making new source material from 23.976 NDF when going to 29.97 as it is easier to track back. DF in this scenario should only be used for the timeline to meet a broadcast delivery spec.

And if you AMA link to the camera originals, and do the conversion in MC while in a 29.97 project, does it drift?

And still on a related note, Avid needs to allow matching different frames rates in a group clip seeing as they already have mix and match maintaining duration.



Michael


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Sarah Furie
Re: 23.976 footage converted to 29.97 is lagging from the camera audio
on May 15, 2016 at 6:52:46 pm

What were the file formats and rates before using Resolve to make the new media? Were you using Resolve 12.5 which has the new feature of adding 2:3? It is in the deliver tab when selecting output rate.

12.3.2

I don't really understand what a 2:3 pull down does versus a 3:2 pull down. Does it affect video and audio and how do you know if it is needed or not?

On a related note, NDF or DF do not affect the playback rate. I would actually recommend making new source material from 23.976 NDF when going to 29.97 as it is easier to track back. DF in this scenario should only be used for the timeline to meet a broadcast delivery spec.

Are you saying I needed to convert to 29.97, but didn't need to convert it into drop frame?

Thanks so much for your help!


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Michael Phillips
Re: 23.976 footage converted to 29.97 is lagging from the camera audio
on May 15, 2016 at 7:27:36 pm

Resolve 12.5 that came out in the last few weeks supports 29.97 delivery of 23.976 sources. I am thinking that 12.3.2 would be doing a motion effect type frame rate conversion which would explain the ghosting.

You do not need to convert to DF when going to 29.97 from 23.976. But you do raise I point I need to test. but I believe Media Composer multicamera just needs to have the same frame rate to be grouped, but sources can be DF or NDF when grouped by IN point. If grouping by TC, then they would need to be the same. But grouping my TC will be hit and miss anyway due to the conversion from 23.976 as there will be +/1 frame (maybe more) differences of where original and new frame boundaries lie.

My overall feeling is that when converting sources from 23.976 to 29.97 that the 29.97 be NDF as there is a known correlation of timecode should you ever need to go back to 23.976. The assumed relationship is "A" frame on timecodes ending in 0 or 5. DF would change that at every minute by two frames in the count.

3:2 and 2:3 are similar ways to say the same thing. It denotes that a field cadence has been done as part of the conversion process. To be super exact, it would be referred to 2:3:2:3 as the cadence occurs over 4 original 23.976 (24) to create 10 fields of video (2+3+2+3). You can have different cadences such as Panasonic's recorded cadence for DV cameras of 2:3:3:2.


Michael


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Sarah Furie
Re: 23.976 footage converted to 29.97 is lagging from the camera audio
on May 15, 2016 at 7:33:58 pm



In my Davinci project, I see a possiblity to click the 3:2 pull down, but when I do, the "playback frame rate" changes to 23.976. Is that what is supposed to happen? I am trying to convert it in Avid and do something different in Davinci too, because the lag is not acceptable.


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Michael Phillips
Re: 23.976 footage converted to 29.97 is lagging from the camera audio
on May 15, 2016 at 7:49:11 pm

That's for monitoring where it adds a pulldown to a monitor that is only 1080i.

In Resolve 12.5, the new feature was the ability to add 3.2 as seen in this screen shot on the delivery tab:



If you can send me a small sample camera original that can be shared, I will make one for you to see if works for you and send it back. Use WeTransfer, or Filemail to send to michael[at]24p[dot]com


Michael


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John Pale
Re: 23.976 footage converted to 29.97 is lagging from the camera audio
on May 15, 2016 at 2:53:11 pm

If you had ghosting, you needed to adjust the pull down in the Motion Effect Editor, as the cadence was off on that clip. But never mind.

Anyway...the assistants were right. Avid does not allow group clips to have differing frame rates, so yes...in this instance, a third party encoder was the way to go. The fact that some clips "didn't work well" in DaVinci, tells me something may have been up with the footage itself, but it's hard to say. Both Avid and Resolve can do this perfectly if the settings are correct and there are no anomalies with the footage.


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