Unable to export interlaced NTSC from Resolve

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Morgan Morel

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Unable to export interlaced NTSC from Resolve

PostMon Sep 13, 2021 10:17 pm

Hello,

At the moment it is impossible to export interlaced NTSC 29.97 files to MOV from Resolve. This feature would be incredibly useful for archival workflows, where we wish to preserve the interlaced nature of files captured from analog video tapes. Thank you!
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Peter Chamberlain

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Re: Unable to export interlaced NTSC from Resolve

PostTue Sep 14, 2021 10:21 am

moved to Resolve forum

Are you using the Studio version?
17.3.1?
And have selected interlace processing in Project Settings?
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Morgan Morel

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Re: Unable to export interlaced NTSC from Resolve

PostTue Sep 14, 2021 7:23 pm

Peter,

Thanks for your response. I have tried using interlaced processing, however the output files are 59.97 Progressive, rather than 29.97 Interlaced. Additionally, the color primaries and matrix coefficients of the files Resolve creates are BT.709 rather than BT.601, however this is a minor concern. At this point if Resolve could create interlaced files it would be extremely helpful for processing archival Standard Definition content.
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Andrew Kolakowski

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Re: Unable to export interlaced NTSC from Resolve

PostTue Sep 14, 2021 8:30 pm

You have to set project correctly (one of the SD presets) and also use one of (not that many) export formats which let you preserve interlacing. On Mac obvious choice is ProRes. On Windows- not sure (you have to see 'Interlaced rendering' option in export menu). Looks like Grass Valley codecs may be the only options, but then those are really working with GV environment only (there is GV codec pack for Windows and old QT as well). ffmpeg supports them as well.
Project's color management needs to be set to custom: SMPTE-C color space and Rec.709 gamma. This is closest you can do, but I would rather avoid Resolve for any SD work.
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Re: Unable to export interlaced NTSC from Resolve

PostWed Sep 15, 2021 10:09 am

Morgan Morel wrote:Peter,

Thanks for your response. I have tried using interlaced processing, however the output files are 59.97 Progressive, rather than 29.97 Interlaced. Additionally, the color primaries and matrix coefficients of the files Resolve creates are BT.709 rather than BT.601, however this is a minor concern. At this point if Resolve could create interlaced files it would be extremely helpful for processing archival Standard Definition content.

There is another viable option: get your deliveries in whatever DaVinchi provides you with, than use ffmpeg to transcode these exactly into your desired codec and container.
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Andrew Kolakowski

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Re: Unable to export interlaced NTSC from Resolve

PostWed Sep 15, 2021 11:12 am

This is basically only solution.
On Mac ProRes will be fine in many cases, but on Windows GV codec will most likely need to be converted using 3rd party app.
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Morgan Morel

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Re: Unable to export interlaced NTSC from Resolve

PostWed Sep 15, 2021 8:33 pm

Thanks to Andrew and stesin for responding with potential solutions. In general I would be happy to export to some intermediate format then use ffmpeg to get back to my target format, in this case either V210 or FFV1. However, exporting to ProRes would be lossy, so that's not an option. I'll look into the the GV codecs and see if it's possible to do a lossless crosswalk. Also, It may be possible to turn the 59.97 Progressive files that Resolve makes into proper interlaced files, but I am pessimistic about this crosswalk being lossless.

Thanks for the heads up on the color info. In general that's an easy thing to change using ffmpeg, it's something we already do for files exported from Premiere, which doesn't properly export color info or aspect ratio data. If you're interested the script that does this is on our GitHub here: https://github.com/bavc/videomachine/blob/master/fix_adobe.sh

If working with SD in Resolve continue to be impossible I'll simply find another solution. That said Resolve is much better than premiere at handling 4-channel audio, which is common on videotape media, which I work with constantly, hence my interest in migrating from Premiere to Resolve.
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Andrew Kolakowski

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Re: Unable to export interlaced NTSC from Resolve

PostWed Sep 15, 2021 11:07 pm

Not sure why you need lossless codec for SD (except for some archive/scientific(?) work).
If you have access to ProRes and need 'lossless' then XQ mode is very close.
GV codecs have only intermediate ones in Resolve exporter (GV lossless is not implemented in export).
None of the lossless exporters (v210 etc.) in Resolve preserves interlacing. No ideas why BM made it this way.

If you want quick and easy change of MOV headers then there is even better way:
http://mogurenko.com
this changes headers on hex level instantly. No re-exports needed just to fix MOV headers.

No idea what problems you have with Premiere and 4 channels of audio. If I were to say then Premiere is actually way easier to work with multichannel audio than Resolve.

No idea why you use 40/27 as SD pixel ratio. I don't know any standard which it's based on.
There is 32/27 or 40/33, but never seen 40/27.
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Re: Unable to export interlaced NTSC from Resolve

PostThu Sep 16, 2021 2:07 am

Andrew Kolakowski wrote:Not sure why you need lossless codec for SD (except for some archive/scientific(?) work).

No idea why you use 40/27 as SD pixel ratio. I don't know any standard which it's based on.
There is 32/27 or 40/33, but never seen 40/27.
Sounds like he’s working with NTSC D1, which is uncompressed 422 component 720x486 (40/27).


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Andrew Kolakowski

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Re: Unable to export interlaced NTSC from Resolve

PostThu Sep 16, 2021 8:21 am

D1 is based on same SD format as we all know. It’s still 720 ( with 704 or 702 active lines), so not sure how 40/27 gets you 4/3 final aspect?
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Andrew Kolakowski

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Re: Unable to export interlaced NTSC from Resolve

PostThu Sep 16, 2021 9:45 am

I just realised that 40/27 is a NTSC frame aspect ratio (720/486).
Problem is that this is not what you should use in MOV headers.
MOV headers need pixel aspect ratio (PAR) which later is applied on top of frame aspect to give final display aspect.
For NTSC 4/3 PAR is either:
10/11 for case when you have active picture using 704 lines ( you should see few black pixels on the sides).
8/9 if you treat whole 720 lines as active picture

If you use D1 as source then you use 10/11 and also add 8 pixels sides crop flag for clean aperture.
When you open such a file in QT7 then it will properly crop sides and display image at final aspect of:
704/480x10/11=1.33(3)

Properly flagged file should look like this:

Image


If you start with SD NTSC preset in Premiere and export ProRes then you will get such a flagging.
There is no need for any corrections.
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Morgan Morel

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Re: Unable to export interlaced NTSC from Resolve

PostMon Sep 20, 2021 7:25 pm

Andrew, thanks for the all info. I think the confusion comes from that fact that we're working with different paradigms. I work with archival tape transfers, in this case we use the entire 720 frame as active video because we cannot control whether or not video information will be in that range, we're simply trying to capture everything we can off the tape. In that case, our active video is 720x486, with a PAR of 9:10 resulting in a DAR of 4:3. We are not using D1 as a source, the source is analog video which has been converted using Black Magic hardware and captured using vrecord, an open source tool developed using the BM SDK: https://github.com/amiaopensource/vrecord

We are very much interested in conforming our digital files to existing specifications, and it seems like we are considering that we use the entire 720x486 frame. In any case, Premiere does not conform to either of these standards, creating 720x486 files with the PAR of 109:120 and a DAR of 109:81. This is why we need to re-write the headers. I may eventually using the tool you provided once I can figure out a way to automate it nicely.

Despite all this, I still would love for Resolve to support uncompressed interlaced exporting so we can move away from using premiere. Again, the main reason for this is that Premiere doesn't seem to support 4-channel audio exports with it's Uncompressed codec. If I'm wrong about this I would love to be shown a resource on how to do this properly. Thanks!
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Andrew Kolakowski

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Re: Unable to export interlaced NTSC from Resolve

PostMon Sep 20, 2021 8:14 pm

Premiere uses "analog" flagging with 704 active lines and 10/11 PAR. There is no way to change it.
Resolve flagging is messed up (unless fixed).

Even if you use 486 then you should not change PARs as those 6 lines should be "forgotten".
As far as I know there were never introduced separate PARs for 486 lines in any specs.
Your value of 9/10 is made up and doesn't really exist.

I would even in your case not bother saving those 6 lines at all (just use 480).
Good explanation:
https://forum.videohelp.com/threads/381 ... ost2476587

If you archiving this footage for future use then not sure why are you trying hard to preserve some ancient analog formats, which don’t translate 1:1 to digital world well. The further you go in time the more those formats will become meaningless. You should optimise those archives for future digital use. No one in 20 years going to try to use them in eg. D1 machine :D
You could even go further and convert them to square pixels or even deinterlace to double fps (but you need good tool for it).

Regardless what you do, there is no need to do any ffmpeg re-export. Just use MOV header tool from Alex and change desired MOV header values instantly (TC, reel name, color space tags etc.).

Premiere supports up to 32 channels of multichannel audio- as interleaved single track or 32x mono tracks.

Why you say it doesn't support multichannel audio?
Last edited by Andrew Kolakowski on Tue Sep 21, 2021 9:40 am, edited 3 times in total.
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Andrew Kolakowski

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Re: Unable to export interlaced NTSC from Resolve

PostMon Sep 20, 2021 9:17 pm

Here is short video showing how to setup multichannel audio in Premiere.
We start with file with 4x mono tracks (not discrete but mono flagged, which freaks out Premiere a bit).

https://drive.google.com/file/d/1tYUNjg ... sp=sharing
(please save video as I will be deleting it from my gdrive)

I use adaptive tracks as I found them most configurable and easy to work with.
Tracks tab in sequence setting lets you specify what main bus (MIX) you want- how many channels. This can be change at any time in the actual timeline which is cool. Tracks config is not important as they come with file.

I overwrite setting for about every imported file to 'adaptive'. This allows you to map any source file channels (tracks) into any desired output channels (if you leave tracks as eg. stereo sometimes you can't route them to further channels).

Video shows me changing config once file is dragged to the timeline. You basically map any source channel to any output channel. Top labels describe source channel number and vertical, output channel.

Once you get to export Premiere show you at start all channels as available and then you decide what to do with them. You basically group them into desired output config. 4 channels can become 1x 4 channels track, 4x mono tracks (these always best to flag as discrete ), 2x 2 channels but not flagged as stereo or simply 2x stereo tracks. You do what you want until all channels are assigned. If you have 6+ channels you can also do 5.1 tracks. This allows basically for any desired config. Only missing bit are language tags and tracks labels for each configured track. Adobe seems to refuse to add it even if I asked many times.
That's it- you can do what you wan up to 32 channels. Basically the same as Resolve or even easier to work (at least for me).
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Morgan Morel

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Re: Unable to export interlaced NTSC from Resolve

PostMon Sep 20, 2021 11:54 pm

Andrew, thanks again for all your help with this. I've saved the video so feel free to delete whenever. I tested this out and it worked!
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