Using Davini to convert 23.976 to 29.97 fps

[Joseph Owens]

[Andrew Franklin] “any small imperfections.”

Properly interlaced, field-cadenced conversion from 23.98P to i29.97 is a particular annoyance for me, as well — FCP7 doesn’t do it at all, it always exports 2:2:2:4 which is fairly jittery. Also of concern for me is the originating codec — some non-intra formats don’t really lend themselves particularly well for FRC — I continue to see material on-air that looks like it was shot at 12 fps. Usually DSLR or GoPro-like origination. Don’t know, but also possibly attributable to a really bad conversion.

The key to getting a good conversion is to make sure that the 2:3 field generation is invoked, and the output is interlaced. This can be extremely time-consuming from a render standpoint for some applications. I have seen Apple Compressor take upwards of 15 hours for a 48 minute show. It does conform with SMPTE A-frame dominance, though, which is remarkable, in a way.

Why you need to Frame Rate Convert is something I am curious about. Is it to integrate the 23.98P material into a 2997i timeline? Otherwise, I might be tempted to leave it alone. The conversion will take care of some future challenges in the workflow, but that really depends on what the ratio of different frame rates might be in the overall project.

The difference between DNx and ProRes in MXF wrappers shouldn’t be all that relevant.

jPo

“I always pass on free advice — its never of any use to me” Oscar Wilde.

[Andrew Franklin]

Joe,

My needs are to utilize 23.976 media in a 29.97 show both at 1920x1080P. All editing will be done in AVID media composer, thus my want for an Avid DnxHD MXF format.

My workaround was to take all the media and add it to a 29.97 sequence in Premiere. This provided the best looking and sounding conversion. It looked 95% perfect, almost like there was no conversion done. Which is what I wanted

The drawback to this method obviously is that I lost the source timecode, and source filenames becuase it was a stringout. The source files were strung-out and exported as one LARGE Quicktime MOV wrapper with an Avid DnxHD codec @ 29.97 FPS (for fast AVID importing).

I’d love to find a workflow that will convert 23.976 to 29.97 Into Avid MXF wrapped DnxHD codec material. Additionally i’d like this to preserve the source filenames and preserve the original source timecode from the raw media (any and all source formats/codecs).

**I know media encoder has a preset for Avid MXF OP1a which is great and all, but unfortunately, when I add these to the MXF media destination and attempt to find them through Avid’s media tool, Avid tells me these are unrecognizable or corrupt files and will not scan the database. It’s basically useless, as far as I can tell.**

[Joseph Owens]

[Andrew Franklin] “**I know media encoder has a preset for Avid MXF OP1a”

I was going to suggest Media Encoder, or even Apple Compressor would do a good job with a batch export. The OP1a MXF format is for transfer to XDCam disk, so it is really more like an “Element” stream file — which makes it opaque to almost everything but the Sony apps for scanning the PDW drives.

Proper 2:3 field cadencing for SMPTE-approved 23.98 -> 29.97 must be interlaced. You might have to look more toward a 60P-type codec if you are trying to achieve a type of progressive scan — but generating the redundant fields is unavoidable. Also, you will lose corresponding frame code no matter what… HR:MIN:SEC will be the same, but 0-23 will change to 0-29 for obvious reasons.

The other application that should be able to do this conversion is Resolve itself, in its “dailies” workflow, with the key point being to preserve the original clip metadata. You would even be able to generate a new AAF for import to Media Composer.

jPo

“I always pass on free advice — its never of any use to me” Oscar Wilde.

[Glenn Sakatch]

Andrew, have you tried playing with the conversion setting inside Avid. Quite often the default setting when you bring a 23.976 into a 59.94 project looks bad, but you can make adjustments in the timewarp properties that will usually clean it up.

Glenn

[Jef Huey]

Glenn is right. Avid will do a perfect job of adding 2:3 pulldown to 23.976 in a 29.97 sequence IF the source material is properly flagged as progressive.

This needs to be done with each clip that is 23.976 and can be done to a group of clip in a bin by selecting the correct column (field motion?) and applying.

Good luck,
Jef

[Sarah Furie]

Hi Jef,

I just converted 23.976 footage to 30 DF in Davinci Resolve 12 and am bringing it into Avid now. What do I need to do in Avid? What is the 2:3 pulldown?

Thanks.

[Marc Wielage]

Resolve 12.5 added the ability to add 3/2 pulldown to 23.976 material for 29.97 renders.