Incorrect interpretation of 23.976 fps

discburn wrote on 9/22/2017, 8:58 AM

Recently, in VPX6, I imported 23.976 footage onto a 1920 x 1080p 23.976 timeline.

I noticed there was 'skipping' occasionally. On checking the video Object Properties, the fps was 23.98.
When I changed the timeline to 23.98, the footage played back smoothly.
However, I was unable to export 23.98 in any 'acceptable' format. (It actually exported as 25fps and out of sync with the audio.)
Exporting at 23.976 just cemented in the 'skipping'.

Using Media Info, I noticed that the fps of my footage was 23.976 (23976/1000).  This came from LumaFusion on my iPad
Then I checked footage that I had imported into VPX6 before, which didn't 'skip'.  In Media Info, this footage was 23.976 (24000/1001).  This came from my Canon 600D.

The 23976/1000 plays perfectly everywhere except in VPX6.  So it seems that VPX6 is 'interpreting' it as 23.98.  That's okay, but I can't go anywhere with it after that.

LumaFusion say they will experiment with a 24000/1001 export, but that 23976/1000 is actually dead accurate and works in every NLE they know of.

Has anyone got experience of this, a workaround or suggestion what I can do?

Thanks!

 

Comments

johnebaker wrote on 9/22/2017, 11:22 AM

Hi

Is the LumaFusion video recorded using the iPad or are you importing this from another device?

Can you post the MediaInfo data of the LumaFusion clip(s) that are causing the problem.

John EB

Last changed by johnebaker on 9/22/2017, 11:22 AM, changed a total of 1 times.

VPX 16, Movie Studio 2025, and earlier versions 2015 and 2016, Music Maker Premium 2024.

PC - running Windows 11 23H2 Professional on Intel i7-8700K 3.2 GHz, 16GB RAM, RTX 2060 6GB 192-bit GDDR6, 1 x 1Tb Sabrent NVME SSD (OS and programs), 2 x 4TB (Data) internal HDD + 1TB internal SSD (Work disc), + 6 ext backup HDDs.

Laptop - Lenovo Legion 5i Phantom - running Windows 11 23H2 on Intel Core i7-10750H, 16GB DDR4-SDRAM, 512GB SSD, 43.9 cm screen Full HD 1920 x 1080, Intel UHD 630 iGPU and NVIDIA GeForce RTX 2060 (6GB GDDR6)

Sony FDR-AX53e Video camera, DJI Osmo Action 3 and Sony HDR-AS30V Sports cams.

discburn wrote on 9/22/2017, 1:12 PM

Hi. The LumaFusion video was recorded using Canon 600D and imported into the iPad app. The original footage going into LumaFusion is 23.976 (24000/1001). Coming out of LumaFusion it's 23.976 (23976/1000) - see attached screenshot 'Media Info'. Very smooth.

It goes into VPX6 that way, and is interpreted as 23.98. Exporting 23.976 from VPX6 comes out at 23.976 (24000/1001).

I should add that, within LumaFusion, the footage is 'cropped' from 16:9 to 2.40:1 or 1920 x 1080 to 1920 x 804, but I don't think that affects the fps (maybe it does!)

Thanks for looking into this!

johnebaker wrote on 9/22/2017, 1:38 PM

Hi

Thanks for the data, tip - you can switch MediaInfo to the Text view and use copy and paste to copy all the text and paste, rather than go through the hassle of editing a screen snapshot.

I suspect the issue is caused by the LumaFusion export, in particular the way the framerate is derived ie 24000/1001 going in - 23976/1000 coming out.

The 24000/1001 is the 'correct rate' for displaying 24 fps video for NTSC display albeit with a very slight slow down of the video.

I suspect that the LumaFusion export is being seen by VPX as 24 fps and is again being adjusted to the 'correct rate' for NTSC export.

Is there any particular reason why:

  1. you are using LumaFusion rather than import the original video directly into VPX?
     
  2. you are shooting at 24 fps?

John EB

VPX 16, Movie Studio 2025, and earlier versions 2015 and 2016, Music Maker Premium 2024.

PC - running Windows 11 23H2 Professional on Intel i7-8700K 3.2 GHz, 16GB RAM, RTX 2060 6GB 192-bit GDDR6, 1 x 1Tb Sabrent NVME SSD (OS and programs), 2 x 4TB (Data) internal HDD + 1TB internal SSD (Work disc), + 6 ext backup HDDs.

Laptop - Lenovo Legion 5i Phantom - running Windows 11 23H2 on Intel Core i7-10750H, 16GB DDR4-SDRAM, 512GB SSD, 43.9 cm screen Full HD 1920 x 1080, Intel UHD 630 iGPU and NVIDIA GeForce RTX 2060 (6GB GDDR6)

Sony FDR-AX53e Video camera, DJI Osmo Action 3 and Sony HDR-AS30V Sports cams.

discburn wrote on 9/22/2017, 1:45 PM

Hi John,

1. LumaFusion is what I use when I'm 'on the road'. It's probably the best NLE for iPad available. And I'm away quite a lot.

2. I like the Canon's 24p 'look'.

Thanks for the 'Text view' tip.

The LumaFusion people are experimenting with a 24000/1001 export. Hope it works!  I'll let you know!

Seamus

johnebaker wrote on 9/22/2017, 5:06 PM

Hi Seamus

Thanks for the info, 'on the road' working is no fun when you are lugging equipment around. LumaFusion certainly looks good on the spec.

. . . . I like the Canon's 24p 'look' . . . .

Interesting - a while ago on another forum there was a long discussion about achieving the 'cine look' and yet no one could define what this 'look' actually was, the only common statement was 24 fps 'looks' better than any other framerate.

Hopefully the LumaFusion people will come up with a fix or workaround.

Cheers

John EB

VPX 16, Movie Studio 2025, and earlier versions 2015 and 2016, Music Maker Premium 2024.

PC - running Windows 11 23H2 Professional on Intel i7-8700K 3.2 GHz, 16GB RAM, RTX 2060 6GB 192-bit GDDR6, 1 x 1Tb Sabrent NVME SSD (OS and programs), 2 x 4TB (Data) internal HDD + 1TB internal SSD (Work disc), + 6 ext backup HDDs.

Laptop - Lenovo Legion 5i Phantom - running Windows 11 23H2 on Intel Core i7-10750H, 16GB DDR4-SDRAM, 512GB SSD, 43.9 cm screen Full HD 1920 x 1080, Intel UHD 630 iGPU and NVIDIA GeForce RTX 2060 (6GB GDDR6)

Sony FDR-AX53e Video camera, DJI Osmo Action 3 and Sony HDR-AS30V Sports cams.

discburn wrote on 9/23/2017, 12:26 AM

Thanks John,

I'll let you know.

Seamus