DV PAL to DV NTSC: Tapes not files

[daamon]

Hi All,

I've had a fairly detailed search, and read through a number of guides - most of them relate to either Xvid or Divx or DVD PAL to NTSC conversions. So I'm turning to a new post for help, as I may have a cunning plan...

I have a friend who has (what I suspect are) miniDV tapes that were recorded on a PAL camcorder in the UK (PAL land). She's now living in the US, and unsurprisingly she's having trouble playing them on her new (and so NTSC, I'm guessing) camcorder.

Here's my cunning plan - let me know if it's nonsense, close, or spot on...

Simply hook up a PAL camcorder to an NTSC camcorder or DVD recorder and do the PAL to NTSC transfer that way. This will be before there's any DV AVI files or MPEGs etc. - just a straight hook up and record.

How's it sound?

[redwudz]

As long as you have access to the PAL camcorder, I would give it a try.

Moving you to the DV forum.

[Cornucopia]

IF it worked transferring the data (which I'm not at all sure of), it wouldn't be any different than the source.

(I assume you were talking about firewire transfer. DV->Analog Video and Analog Video->DV would have the same usual format conversion problems, PLUS you would have D/A/D conversion losses AND DV-compression generational losses)

Remember that the data is already formatted for a certain system. The Macroblocks, etc are a certain size and order. The Flags are still the same.

This would be the same as just putting the PAL tape in the NTSC camera and trying to play it out (which your friend has already told you doesn't work).

Here's what you could/should do:

1. Get PAL camcorder. Put PAL tape in it.
2. Do Firewire transfer to PC. Save as (PAL) DV-AVI file.
3. Use Virtualdub, etc to convert PAL to NTSC, saving as (NTSC) DV-AVI file.
4. Do Firewire tranfer back to (NEW) NTSC camcorder.
Done!

Scott

[daamon]

IF it worked transferring the data (which I'm not at all sure of), it wouldn't be any different than the source.

It was this that I wasn't sure of.

I assume you were talking about firewire transfer.

Yes. As...

DV->Analog Video and Analog Video->DV would have the same usual format conversion problems, PLUS you would have D/A/D conversion losses AND DV-compression generational losses

...I'm aware of the losses incurred by doing it this way, but wasn't sure about the format conversion problems.

Remember that the data is already formatted for a certain system. The Macroblocks, etc are a certain size and order. The Flags are still the same.

This would be the same as just putting the PAL tape in the NTSC camera and trying to play it out (which your friend has already told you doesn't work).

I wasn't sure if the NTSC DV cam would take an incoming source, of any format, and "NTSC it". It sounds like it won't... Oh well - it was worth asking.

Here's what you could/should do:

1. Get PAL camcorder. Put PAL tape in it.
2. Do Firewire transfer to PC. Save as (PAL) DV-AVI file.
3. Use Virtualdub, etc to convert PAL to NTSC, saving as (NTSC) DV-AVI file.
4. Do Firewire tranfer back to (NEW) NTSC camcorder.

Step 3 was going to be my next method - and it's here that I have no experience.

I've already mentioned that I've had a fairly detailed look and found some guides - there seems to be a number of approaches, but I'm not sure which one is suitable for PAL DV AVI -> NTSC DV AVI.

There's mention of 23.976fps and 29.97fps. Some use pulldown, some don't. Depending on which one you go for, some need to stretch the audio in BeSweet, some don't.

I'm more than happy to give it a go, and am fairly comfortable with a semi-technical approach - I've learnt enough from this site to feel confident about giving it a go, it's just the detail I need.

Does anyone know of a guide that's suitbale for PAL DV AVI to NTSC DV AVI? My main objective is end quality - I don't mind a bit of involved antics with a few bits of software.

P.S. Thanks for the help so far.

[Cornucopia]

You can go 2 different routes, quick-n-dirty or slow-and-exacting.

First route will not worry about the aspect ratio staying correct (usually 4:3) or about the framerate's relationship with the frames adjusting appropriately (so time will change).

Basically, you could crop 576-->480, and set framerate from 25-->29.97, and save the result.
So 10 min. = 15000frames (at 25fps). Changing the framerate to 29.97 means it will last 8 1/3 min.
This would be a quick change--mainly to be able to see the material.

To do it correctly you want to frame-rate convert (interpolating frames), which will maintain the time. You also want to Resize (Precise Bicubic or Lanczos methods are very good here), which will maintain the aspect ratio and give you the best way of retaining resolution/sharpness and smoothness. Be mindful of interlacing, though! (May need to convert first to 50fields persecond, then convert to 59.94fields, then down to 29.97frames) I actually have a similar, but more extreme method that I occasionally use for real smooth converts.

This is all assuming that you have true Video-based material (interlaced PAL) and are going to standard interlaced NTSC. Since you talked about camcorder footage, that should be appropriate (unless your friend was doing telecine with their camcorder). So no need to worry about film rates here (23.976) or IVTC...

Scott

[daamon]

Hi Cornucopia,

Cheers for the useful info. The source material is normally shot PAL miniDV - so it's not telecined and will be interlaced.

Being the perfectionist I am, I'd want it to be done properly - i.e. the "slow-and-exacting" method - to get smooth conversions.

So, I start with a PAL DV AVI. I then:

1) Extract audio with VirtualDub to a WAV file.
2) Resize filter in VirtualDub (Precise Bicubic or Lanczos) to 720 x 480.
3) And then...???

What comes in step 3 and beyond? How (i.e. tools and steps) do I convert to 50 fields per second, then to 59.94, then to 29.97 frames per second?

I'd be interested to hear you extreme method and what differences in smoothness result over the "normal" method you've described.

As either method retains running time, there's no need to alter the audio by stretching or shrinking it in an audio editor. Correct? Simply a case of recombine audio with (now) NTSC DV AVI?

Again, thanks - it's really appreciated.

[Cornucopia]

(I hope I haven't been leading you down the wrong path!)

To be honest, most of the time, I either use Cleaner/ProCoder/etc, Adobe AfterEffects (very good in this area), or Advanced DV Format Converter (now owned by Focus), or I use a proprietary method.

With Virtualdub, you could just do [Video | FrameRate | Convert to fps : 29.97], and the resize (like you were thinking), and maybe a smart, motion-compensating/area-based deinterlace filter.

Or a similar AVISynth script (probably a little more versatile in this respect).

My proprietary method, which I don't think you'll care to try, uses lots of uncompressed intermediate files (which are HUGE!).

Basically goes like this:

1 pass de-interlacing with interpolated even fields, 1 pass with interpolated odd.
1 pass with black in place of even fields, 1 pass with black in place of odd.
Overlay pt 2 over pt 1, with a mask for the black areas (even, then odd).
(This allows the original lines' quality to be maintained)
Saving each out as still picture sequences.
Rename alternating sequences (by evens, by odds).
Concatenate the sequence back into an AVI-now with 59.94 PROGRESSIVE frames.

I do a "Morph" to interpolate frames.
Sometimes for the extreme smoothness effect, I up-rate it to the common multiple (300fps), and do a "frame blend" down to 50fps, also saving a version that just copies the original frame (the 300th of the sequence) that is still common to both. Overlay & replace here also.

Then, use alternate lines from the Progressive frame pairs, creating a new interlaced file.

This all uses a number of video and stills utilities.

There are others here that have other, more conventional-but still high quality, workflows for this kind of thing. Check with Neuron2, IIRC, to start...

Scott

note: if in my examples I used the wrong system, sorry. just use the appropriate rate for the stage you're in.


>>>>>>>>>
edit: Yes, the audio would then be left alone.

[daamon]

Wow! I can see why your method produces the results it does - maybe I'll give it a go when I've cracked a simpler initial approach. The old "learn to walk before I run" philosophy...

So am I right in thinking that the conversion to 50 fields per second, then to 59.94, then to 29.97 frames per second isn't something that can be done in VirtualDub?

I'm not familiar with AviSynth - though I'm prepared to give it a go if it can do the job and it's not too tricky to learn.

The irony now is in I'm wanting to take on this challenge, meanwhile my friend thinks she'll be able to get a hold of a PAL cam so she can view the original tapes.

[Cornucopia]

[quote="daamon"]So am I right in thinking that the conversion to 50 fields per second, then to 59.94, then to 29.97 frames per second isn't something that can be done in VirtualDub?

I'm not familiar with AviSynth - though I'm prepared to give it a go if it can do the job and it's not too tricky to learn.[quote]

Yeah, just do a straight conversion from 25 to 29.97 (or vice versa).

AVISynth is good, but I have trouble with it. Never was great with batch scripting.

Scott

>>>>>
Try using 29.97, but also try 30fps and see which runs better (as long as they still sync up with audio). Some apps have trouble with the non-integer framerate business.

[daamon]

Yeah, just do a straight conversion from 25 to 29.97 (or vice versa).

Easy enough - but doesn't that either produce a jumpy output or affect the running time and hence getting the audio out of synch (though fairly easily addressed - strecth in an audio editor)? I'll give it a go and see what I get - I guess I was expecting it to be more involved than that...

Try using 29.97, but also try 30fps and see which runs better (as long as they still sync up with audio). Some apps have trouble with the non-integer framerate business.

OK. Cheers.

I'll report back how I get on...

[daamon]

Well... Knock me down with a feather. A PAL to NTSC conversion in VirtualDubMod that was straight forward and worked...

I tried it in VirtualDub ("Framrate Conversion", NOT "Source Rate Adjustment"), but the resultant DV AVI had a framerate of 29.97, despite me setting 29.976. I tried the same in VirtualDubMod and GSpot reported a fps of 29.976.

[EDIT: 29.97 is accepted as close enough, as per manono below.]

Too easy... Here's what I did for those who are curious:

1) Open VirtualDubMod (I've got v1.5.10.1) and open your source PAL DV AVI file.

2) Click: Video -> Filters -> Add.

3) Add the "Resize" filter and set as 720w x 480h and "Filter mode" as "Lanczos3". Click OK to close window(s).

4) Click: Video -> Framerate. The "Video frame rate control" window opens up.

5) In the "Frame rate conversion" section (2nd of 3), click the "Convert to fps" radio button and enter 29.97 in the now active field.
[EDIT: Changed 29.976 to 29.97 as per manono below.]

BE SURE to NOT select anything in the "Source rate adjustment" area... Click OK to close window(s).

6) Click: Video -> Compression. And select the Panasonic DV Codec (if it's installed), or any other usable DV codec.

7) Click: Video -> Full processing mode. If it's not already selected...

8) Click: File -> Save as... and name your file then OK to save.

It'll process for a while and you'll have a video in synch with audio NTSC DV AVI file.

I checked it out by dropping it into a new Adobe Premiere Pro project with the default NTSC settings and there was no need to render the NTSC file. I dropped the original PAL file in and that was shown as requiring rendering.

I then checked both files in AVICodec and there was no loss in the %ge quality (though not sure exactly what that means). In fact the PAL source was shown as 90%, and the resultant NTSC was shown as 98%. Now I know that quality can't be magically added - but at least it wasn't below 90%. I guess that means something good...

Anyway - to my eye they looked identical and the audio was in synch. The only obvious difference was the resolution.

Sweet! Thanks all, especially Cornucopia!!!

[JohnnyMalaria]

But how is the fluidity of the resulting video? To do frame rate conversion *properly* you have to calculate the motion in the video and interpolate to get the new frames at the right points in time. A simpler way is to blend adjacent frames to help mask the jerkiness that you will otherwise get.

If you are getting the jerkiness, then you can achieve exactly the same result with.....Movie Maker. Configure it for an NTSC project, drop the PAL file on the timeline and save the new file. It takes care of the audio, the resizing of the frame with proper allowance for interlacing etc. But it will be jerky. You will notice this most on panning shots.

John.

[manono]

click the "Convert to fps" radio button and enter 29.976 in the now active field.

For future reference, it's 29.970030fps, or 29.97fps for short. I don't know what effect that will have, if any, on your ability to author it.

[JohnnyMalaria]

Actually, it is *EXACTLY* 30000/1001 which is 29.97002997002997002997002997 recurring.

[lenti_75]

the easiest way is this:

capture the PAL to avi - I use Ulead videostudio make sure you work on pal system.
use Procoder to encode from Pal-Ntsc.
burn it as ntsc to dvd or back to mini-dv.

the easiest and the closest to perfect conversion. I tried a lot fo software for pal-ntsc conversion and Procoder is the best

this is how I do it for system conversions.

[daamon]

But how is the fluidity of the resulting video?

It was absolutely fine on the clips I selected to trial it out on - admittedly they were few and from a wedding I did recently, so no fast movement was involved. Just slow pans.

But this got me thinking, so I decided to look closer. When I previewed the original PAL DV AVI on PowerDVD there were no interlacing issues, as expected (PowerDVD deinterlaces). However, when I did the same with the NTSC DV AVI clip, I did notice that with a slow pan, the NTSC DV AVI clip had visible interlacing artifacts - just like if you watch interlaced material with software that doesn't deinterlace.

Fortunately, you also posted this:

A simpler way is to blend adjacent frames to help mask the jerkiness that you will otherwise get.

I used this as inspiration to also include the "smoother" filter in VirtualDubMod set to 100. Its description is "Dynamically smooths an image while trying not to smear edges".

I put this second in the list to the resize, figuring it'd be better to do things in that order.

The resultant "smoothened" NTSC DV AVI came out with no obvious interlacing artifacts - pausing and scrutinising the image reveals some, but far less noticeable than previously. I've not yet encoded to MPEG to check it out as DVD on a TV, but I suspect it'll look fine.

I didn't notice any obvious degradation to the image in general.

I don't how this will work with footage containing faster motion.

For future reference, it's 29.970030fps, or 29.97fps for short. I don't know what effect that will have, if any, on your ability to author it.

29.97 it is - edited, see above. Thanks.


I've noticed something else... In GSpot, the following is reported for the PAL DV AVI:

FAR: 1.250 (5:4)
PAR: 1.000
DAR: 1.250 (5:4)

For the NTSC DV AVI, the following is reported:

FAR: 1.500 (3:2)
PAR: 1.000
DAR: 1.500 (3:2)

Is this change to the aspect ratios to be expected?

[manono]

Is this change to the aspect ratios to be expected?

Yes, PAL=720x576. 720/576=5:4=1.25
NTSC=720x480. 720/480=3:2=1.5

[daamon]

Thanks manono.

I guess the next thing is to try the method on footage with faster moving subjects and / or faster pans.

Then there's encoding the newly created NTSC DV AVI to DVD.

But I'll leave both of those to someone else - I think I have enough to potentially help my friend. The only drawback I can see is capturing numerous tapes, each potentially 90 mins long, converting to NTSC and then saving back to tape.

Fingers crossed she'll be able to get the PAL cam she's talking about!!!