Convert 24p NTSC Sequence to PAL

I have a 24p 10 bit SD sequence that I want to convert to a PAL Quicktime movie for eventual output to PAL Digibeta and DVD. Quality is priority, but I'd like to do this within FCP Studio to save $. I'm guessing I'll do this either within FCP or with Compressor but not exactly sure how. When I converted this sequence to 29.97 before, I just dropped the sequence into a 29.97 sequence, rendered, and voila. I'm wondering if this is the same case. My concern is I've heard that audio is affected once converted to PAL. Any info would be much appreciated!

Best,
Alexander

The canonical way to convert from 24p to PAL is to conform to 25p with Cinema Tools, then render the 25p shot out as 50i. This speeds everything up by 4%.

If you wanted to invest a lot more time, you could try using Compressor to do an optical-flow retime to 50i directly, but this would have the side-effect of softening your footage, and you might not like that. Also, it'll take ages.

Incidentally, the way to go from 24p to 29.97 is emphatically not to drop your 24p footage into a 29.97 timeline. Final Cut, for reasons that remain inscrutable, does not insert 3:2 pulldown when converting from 24 to 29.97. I forget the actual pulldown pattern it uses, but it's not the normal one. You can get from 24p to 29.97 either by using After Effects to insert pulldown on render, or by playing your 24p timeline out of a Kona system to tape; the Kona boards insert pulldown automatically.

The difference between NTSC and PAL isn't just in the frame rates. Also the black levels (which for NTSC is handled by the output device). And the frame size.

To do it in FCP, do as Jeff mentioned- drop it into Cinema Tools to get it to 25 fps. Then drop that into Compressor, drop a PAL Uncompressed SD codec on it, set resizing to best, And wait. And wait. And wait. Or re-size and render in FCP. Or use Graeme Nattress' Standards Converter.

Or send it to a facility with a hardware converter to do it all in real time.

It's not really 50i, Jeff. It's 25p. I don't think you can fill in the temporal resolution of interlace.



www.strypesinpost.com

If I go the Cinema Tools route, doesn't it speed up audio by 4% so there's pitch difference? That scares me. Also why should I convert to 50i, couldn't I just keep it as 25p?

Yes, it does pitch the audio up slightly. This is a natural consequence of the conversion to PAL. A great many feature films shown in PAL countries sound slightly higher pitched than they did in theaters because of the 4% speed difference.

As Strypes said, you can send this out to a facility with an Alchemist or similar standards converter; it'll convert your 24p material to 50i through image interpolation. This will result in a softer image, but you might not care.

And for the record, standard-definition PAL is always 50i. PAL, like NTSC, is an interlaced broadcast format. There is no support in PAL for progressive scanning. You can work in 25p if you like, but before that actually ends up on anybody's television, it will get converted to 50i. The odd field and even field will just correspond to the same original film frame.

(Likewise, NTSC is always 60i, period, no exceptions. The shorthand "30p" just refers to a 60i frame where both fields were captured during the same shutter opening.)

So I guess there's no way around the pitch difference then. Funny to hear Brad Pitt sounding like Angelina Jolie.

Would love to go Alchemist route, but it'll be too expensive. I'm gonna do this via Compressor for now. If that doesn't work, then I'll try Nattress Standards Converter.

I've recorded 24p DVD's, you sure they don't have 25p DVD's in PAL world? Where does the conversion to 50i take place?

It's not a conversion at all. It's inherent in the PAL broadcast standard. A PAL television signal is 50i, period. Just like NTSC is 60i, period, end of paragraph.

In the US, most DVDs are encoded in 24p ? actually 23.976 frames per second. But the signal that actually comes out, down the wire to the television, is 60i. A 3:2 pulldown pattern is added to the signal to get it into a 60i format. Similarly, in PAL-land, a DVD with 25p data on it will come out of the back of the DVD player as 50i.

(Note that this applies only to analog television. In the digital realm, all bets are off, since the folks who codified the various standards for digital SD and HD television seemed to be of the opinion that if one standard was good, seventeen would be seventeen times better.)

hi, alex.

i'll second the cinema tools speed increase.

i'd probaby "conform" to 25,
then drop that file into a PAL sequence in FCP (uncompressed or ProRes), which should deal with the frame size and export
make sure your timeline settings > video processing had scaling set to "Best" quality


there are audio tools that can deal with the pitch thing.
i think in a similar thread a while back, someone wrote back saying they'd used Audacity. (free-ware)


cheers,
nick

>Yes, it does pitch the audio up slightly.

Not necessarily. It depends on what's doing the retiming. Soundtrack Pro can do retiming without changing the pitch. I'm sure Logic or Pro Tools can handle that too.

> it will get converted to 50i. The odd field and even field will just correspond to the same original
>film frame.

Yup. That is the idea. 25p, but played back in fields for interlaced broadcast, similar to 30p. Re-interlacing, if that is possible, will result in a loss of spatial resolution.

I'll do something similar to what Nick mentioned- the Cinema Tools, then resize in FCP. Or Compressor with Frame Controls, resizing set to "best". Send original audio to Soundtrack Pro to add the pulldown

The other way to do it, is to conform to 24p (not 23.98), add a 24&1 pulldown and resize in FCP, FCP does the pulldown on playback.



www.strypesinpost.com

"Yes, it does pitch the audio up slightly"

if "it" means Conforming in Cinema Tools, then yes, it incontrovertibly does pitch the audio!

i'd be wary of speed changing the original audio to match a conformed picture.
although i haven't tried this, the chances of it drifting in sync seem high to me.

i would prefer to PITCH correct the audio of the conformed video file.

if you DO try to manipulate picture and sound separately, make sure you put a sync pip at both the head AND tail of the movie.


nick

Anyone here have a decent tutorial for Audacity or Soundtrack Pro to fix pitch change caused from NTSC to PAL conversion? I don't have Protools. Thanks.

I don't work in 24p much, but here's what I'll do:

Export the full audio mix in aiff, with iso tracks if you're going out for broadcast make sure you have sync pips as Nick mentioned, conform the video together with the audio. Then check the total duration between the sync pips, calculate the total number of frames, drop the aiff files into soundtrack, do a time stretch, drop it back into FCP, check for sync.

Soundtrack Pro has a pulldown option which you can try out as well.



www.strypesinpost.com

A good straightforward tutorial I found by Tim McLaughlin on Creative Cow:

Step 1:
Dupe the file in question and label as "25fps".
Otherwise, Cinema Tools will "conform" over your existing 23.98 file.

Step 2:
Use Cinema Tools to conform the file to 25fps. This will translate the file to 25fps, slightly speeding up the file (roughly 4 %). A slight change in pitch can be noticeable, depending on content.

Step 3: (not required, but I recommend it)
Use QT Pro to export a 48k AIFF of the newly conformed file. Load the AIFF into Audacity (or your choice of audio editor) and pitch-shift the file to play 4% slower. Export this new file with a "pitch" tag in the file name for the sake of sanity. Audacity did a surprisingly clean conversion, I was very happy.

Step 4:
Run the conformed QT (and pitch-shifted AIFF) through Compressor. Load 'em into DVDSP and make your new PAL DVD.

Now admittedly, this is not the work flow for everyone. Many would argue that it would be best to pitch-shift the audio file before conforming, etc. And in checking with some of my European resources, I've been told that many programs aren't adjusted for pitch, they simply run with the 23.98 to 25 conversion and are done with it.

Also, conforming this way does speed up your video about 4% (ie: a 100 min program is only 96 min log after conforming).

However, with this method, a frame is mapped to a frame. You are making a true 25p DVD, no frame-blending, no interlacing. And by adjusting the pitch of the audio AFTER the conform, you won't need to worry about audio sync issues - the file duration is still the same, you're merely pitching it a bit.

Conforming is near-instantaneous. And exporting and pitching the audio takes only a couple of minutes.

Without jumping through a bunch of hoops, this is a very quick an easy way to get your HD content to PAL-land.

Tim McLaughlin
Avid and Final Cut Editor

As for the audio, I tried Audacity but I couldn't find the help file, it crashed opening certain types of files, or just refused to open files. I couldn't find a tutorial through Google or the Audacity website taking me through the steps.

So I went to a sound editor today who uses Protools. He recommended going back to the original 23.976fps Quicktime file, and tried to use Pitch Shift>Time Shift function to redo the sound. We had sync issues. Protools had a conversion function "NTSC->PAL- 4.269~%" which slightly differs from my calculation that an increase from 23.976 fps to 25fps is an increase of 4.2709376%.

So I recommended he stick to the Cinema Tools conformed files, as Nick Meyers recommended. He then did pitch shift following a recommendation by Noiz2 on DVXuser:

"Well traditionally you don't pitch change it at all. Don't know audacity but STP should have a pitch changer that will leave the length the same. You would then want to lower the pitch by 50 cents (50/100's of a semitone)."

The 50 cent of a semitone was spot on, we compared it to the original file. Just wanted to share my experience. Thanks!

Great you got it worked out in the end.



www.strypesinpost.com

Thanks to you guys!

One step forward, one step...

I've noticed that when I do the rescaling within FCP images look somewhat blurry and text has ghosting (aliasing, stepping?) around the edges. At the top and bottom of the screen there's a line that resembles a prism effect. Perhaps I'm not doing something right. My steps were:

1. Conform 23.98 10 bit uncompressed NTSC to 25fps using Cinema Tools
2. Drop the file into a PAL 10 bit uncompressed sequence. FCP will say "This clip does not match sequence settings... Change sequence settings to match the clip settings?"

Yes- Sequence doesn't need rendering but under sequence settings, General tab the frame size is 720x486, Aspect ratio is CCIR 601 NTSC (40:27), Pixel aspect ratio is NTSC - CCIR/601 DV (720x480), Field domainance is lower (even). For Video Processing tab I've got "Render all YUV material in high-precision YUV" and "Motion Filtering Quality" at "Best". Under Render Control tab "Master Templates and Motion Projects" Quality is "Best", and "always use best quality when rendering movies" is checked.

No- Entire sequence render bar is green. Under general tab the frame size is 720x576, Aspect ratio is CCIR 601 PAL (5:4), Pixel aspect ratio is PAL - CCIR/601 DV (720x576), Field domainance is upper (odd). Settings under Video Processing and Render Control tab are the same as above.

From here I drop in my pitch shifted AIFF and export a Quicktime movie. Result is not great. Will Compressor or Nattress Standards Convertor do a better job of converting the Frame size, aspect ratio, pixel aspect ratio and field dominance? Or is this just a part of the process that's unavoidable?

Thanks,
Alexander

2. Drop the file into a PAL 10 bit uncompressed sequence. FCP will say "This clip does not match sequence settings... Change sequence settings to match the clip settings?"

NO!
you do not want to match this clips' settings.

this clip is an anomaly.
is has an NTSC frame size and a PAL frame rate.

you want to put this clip into a true PAL sequence, and let FCP scale it to fit.

to that end you will also want to open the sequence settings, go to "Video Processing" and set Motion Scaling to "Best"

as for picture quality, remember to only judge that on an external monitor,
not by eye-balling the FCP canvas.



Nick

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PS:
pitch shifting after-thought:
playing around in QuickTime (7.6) i notice there are now controls for pitch.
seems to do a ok job of it, too, (listening on a laptop!)
but the controls are not fine, and you are just guessing as to what you are doing.