I have a question about converting 48 khz to 48.048 khz.

[Ryan Elder]

Okay thanks. But if I leave the sample rate the same, but I convert the footage from 23.976 fps to 24 fps, the sound then isn't as long as the video. So if I am to leave it the same, how do I change the speed then to match the video? Should I just use the rate stretch tool and stretch the audio to length of the video?

[Paul R Johnson]

I think, if I have followed this correctly, is what people are saying is that you should not try to shoot video in drop frame - it's no longer a valid proposition, so if you record in any of the common versions, then the audio IS 48K, not the .1% difference because there is no dropped frame to be pulled up.

If you record video at 1080 and above at any frame rate above 23fps, then it will NOT be drop frame NTSC, and that is where the problem comes from. 24, 25,30 are all frame for frame accurate. I'm not even sure there is an HD drop frame format now, is there?

[Brian Drysdale]

Shooting at 23.976fps is pretty standard in NTSC countries (unless shooting film), otherwise you can run into issues with time code and post production can become a nightmare. Many video cameras shoot at 23.976fps, while saying 24 fps as a short hand. I wouldn't bother about pitch changing for this. you probably hear it all the time and don't notice.

In Europe 23.976fps is not issue, because you use whole frames for the time code, so 24 fps can be used and 25fps is for TV (some low budget features uses this). However, shooting at 24 fps may require pitch change because of the 4% speed difference when being transmitted at 25 fps. Even then it may not work with all soundtracks because the process can be objectionable with certain types of music.

[Gary Nattrass]

Originally Posted by Paul R Johnson

thank God for that - I was imagining all kinds of crazy things happening if you had to transcode audio to package it up.

I did have a look in Premiere and Media Encoder and couldn't find any trace of this audio format - so makes sense now. 48K and leave out there!

Potentially yes but pull down and pull up sample rate has always been there since the advent of digital.

Editors liked working with a 30fps timeline so pull down and pull up sample rates were defacto to suit the 29.97 frame rate that was used in TV.

As for HD I would have thought that if you have 1080i 48khz or 25p/30p you just export a 24p version for festivals etc.

The great thing about standards is that there are so many and at AMS Neve when I was there in the early 90's we had to deal with all sorts of chaos as people mixed and matched drop rate timecode and sample rates.

[Ryan Elder]

Oh okay, well I keep having issues cause when I try to convert 23.976 fps to 24 for a DCP package, the video is then longer than the audio it seems.

[Brian Drysdale]

I would check your workflow for doing this, you may find that there is a setting/procedure for this operation..

I suspect you aren't the only person doing the 23.976 fps to true 24 fps procedure with a digitally shot film, so that procedures will be established, if somewhat confusing. https://simpledcp.com/notes-on-frame-rate-conversion may be a starting point.

[Cary Knoop]

Originally Posted by Paul R Johnson

I think, if I have followed this correctly, is what people are saying is that you should not try to shoot video in drop frame - it's no longer a valid proposition, so if you record in any of the common versions, then the audio IS 48K, not the .1% difference because there is no dropped frame to be pulled up.

If you record video at 1080 and above at any frame rate above 23fps, then it will NOT be drop frame NTSC, and that is where the problem comes from. 24, 25,30 are all frame for frame accurate. I'm not even sure there is an HD drop frame format now, is there?

"Drop frame" or "Non-Drop Frame" does not refer to the framerate but to how the timecode counts frames.