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Old 15th November 2012, 17:29   #1  |  Link
srfscenar
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HD to DVD

Hi all,

I have been asked which format to use and I need your help.

I will be given one of the following:
Apple ProRes HD 422HQ 50i
or
Apple ProRes HD 422HQ 25p.

The above file will be used to encode an Mpeg2 PAL file with CCE
to use it for creating an SD DVD.

Which one should I use?
The 50i or the 25p?

Thanks!
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Old 15th November 2012, 18:45   #2  |  Link
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If the 50i video file carries 50 individual fields which indeed contain individual steps of motion then you definitely should use the 50i file for DVD creation.
If you don't, you would throw away 50% of motion which you otherwise would have been able to put on DVD no problem.
So, check the 50i file for interlacing. If there's no interlacing then it's just the flag saying it's interlaced and the video contained within is actually 25p anyway. However, in that case there's pretty much no difference between the two files, so just grab the 50i.


However, I hightly suggest not to simply dump the ProRes file on CCE and expect it to make a great MPEG2 for DVD out of that.
CCE is a good encoder, no question. But it's an encoder – it's not particularly good at all the other things (most important here: scaling!) that need to be done prior to encoding.

Better use AviSynth for that.

Last edited by TheSkiller; 15th November 2012 at 18:48.
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Old 15th November 2012, 19:04   #3  |  Link
srfscenar
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Thank you!

So, in any case, I should use the 50i, right?
Why 50i is better than 25p for DVD use?

And thanks for the tip for CCE!
Maybe I will downscale it to 720x576 from FCP.



Quote:
Originally Posted by TheSkiller View Post
If the 50i video file carries 50 individual fields which indeed contain individual steps of motion then you definitely should use the 50i file for DVD creation.
If you don't, you would throw away 50% of motion which you otherwise would have been able to put on DVD no problem.
So, check the 50i file for interlacing. If there's no interlacing then it's just the flag saying it's interlaced and the video contained within is actually 25p anyway. However, in that case there's pretty much no difference between the two files, so just grab the 50i.


However, I hightly suggest not to simply dump the ProRes file on CCE and expect it to make a great MPEG2 for DVD out of that.
CCE is a good encoder, no question. But it's an encoder it's not particularly good at all the other things (most important here: scaling!) that need to be done prior to encoding.

Better use AviSynth for that.
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Old 16th November 2012, 11:02   #4  |  Link
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What is the original format? 50i or 25p?

For the DVD 50i might be the logical choice in the absence of other evidence.
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Old 16th November 2012, 11:10   #5  |  Link
srfscenar
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Quote:
Originally Posted by Ghitulescu View Post
What is the original format? 50i or 25p?

For the DVD 50i might be the logical choice in the absence of other evidence.
I think it is 23.98 because they write:
1080 23.98
Cross conversion to 24p fps, 50i fps, 25p fps

So I guess, they convert the 23.98 to the other formats.

Does this say anything to you?

Thanks.
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Old 16th November 2012, 14:45   #6  |  Link
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Quote:
Originally Posted by srfscenar View Post
Does this say anything to you?
Yes, it says that they'll do a fps conversion, which you should better do it yourself.

The best bet would be to create a NTSC DVD, most if not all PAL equipment is able to play them.
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Old 16th November 2012, 15:27   #7  |  Link
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Thanks!

Everything noted!

Thank you all!
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Old 17th November 2012, 13:03   #8  |  Link
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Alright, so things aren't as easy as it seemed from your first post.

In that case, like Ghitulescu mentioned, you most likely want to get the original 23.976 fps video file from them.
The only reason I can think of why you'd still want them to give you something more PAL compatible would be if they did a proper conversion to 50i (via Pulldown) or 25p (via Speed-Up) so that you don't have to deal with that and have an easy time making a PAL DVD.



At this point you have to decide between these two:

1) Simply make a NTSC DVD from the 23.976 video. Easy. But slightly inferior to a proper PAL DVD. Also it won't play properly on all TVs in Europe, but almost all.

2) Make a PAL DVD either from 23.976 by doing it yourself or by requesting 25p or 50i.


I personally wouldn't blindly rely on someone doing a proper frame rate conversion for you. My experience is, most people don't know what they are doing (sometimes even the professionals) and think their NLE does it magically right.

Last edited by TheSkiller; 17th November 2012 at 13:06.
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Old 17th November 2012, 14:04   #9  |  Link
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Quote:
Originally Posted by TheSkiller View Post
I personally wouldn't blindly rely on someone doing a proper frame rate conversion for you. My experience is, most people don't know what they are doing (sometimes even the professionals) and think their NLE does it magically right.
Thanks Skiller,

OK, the best way I know to convert the 23.98 --> 25, is to use Cinematools for converting the Video and Audio streams
and then take the audio and correct the pitch with ProTools, right?

Is there a better way?

Thanks!

PS: If we take the 25p, it will come directly from a MAJOR studio from US. I think I will trust them to do the conversion!
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Old 17th November 2012, 21:18   #10  |  Link
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Quote:
Originally Posted by srfscenar View Post
OK, the best way I know to convert the 23.98 --> 25, is to use Cinematools for converting the Video and Audio streams
and then take the audio and correct the pitch with ProTools, right?

Is there a better way?
Probably yes (and faster).
I don't know Cinematools, but to be honest since 23.976 -> 25 via Speed-up is a two-liner Avisynth script (excluding audio), I'd just do it using AviSynth. There's one huge advantage: you can be sure it does exactly what you tell it to. Also, while you're at it, that's where you could do the scaling to DVD frame size.

There are some quirks and tricks concerning the scaling. Scaling from HD to SD is surprisingly a rather complex process actually.
Well, it all depends on how much effort you want to put into it, since there are no "best" settings but consider the following to be most likely quite a bit superior compared to what most NLEs would spit out.


Code:
SourceFilter("1080p23.976 Source") #depends on source
AssumeFPS(25) #Speed-Up to 25 fps


#scaling, here is a suggestion specifically for HD to SD

Sharpen(0.5, 0) #pre-sharpen horizontally to better keep hor. details
BlackmanResize(704, 576, taps=4)
Blur(0, 0.6).Sharpen(0, 0.4) #mild vertical low-pass
The result of that script would either be saved to a lossless intermediate or you can feed it directly to CCE.
704x576 is a valid DVD frame size by the way, without going into further detail, it's a good thing to use.


The only thing that is a bit troubling in the Speed-Up process is the audio. Video stays unchanged, the frames are just played back faster.
A pitch-corrected conversion style would be desireable.

Basically, you need to strip the original audio from the video file and use some audio editor to apply Speed-Up. Almost every audio editor has a preset for that.
After that the audio needs to be encoded to a DVD compatible audio format (MP2, AC3 or WAV, at 48 kHz) and can then be used together with the CCE encoded MPEG2 video to author a DVD.


Quote:
Originally Posted by srfscenar View Post
PS: If we take the 25p, it will come directly from a MAJOR studio from US. I think I will trust them to do the conversion!
Right, one would think so. And I hope that's the case.
But let me just mention this: quite many times I have seen videos here on PAL TV, say major music videos for example, which originated from 23.976 fps, converted in a truly awful way where one frame each second was simply shown twice (result: ugly stutter every second). Everything is possible nowadays...

Last edited by TheSkiller; 17th November 2012 at 21:26.
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Old 18th November 2012, 06:47   #11  |  Link
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Quote:
Right, one would think so. And I hope that's the case.
But let me just mention this: quite many times I have seen videos here on PAL TV, say major music videos for example, which originated from 23.976 fps, converted in a truly awful way where one frame each second was simply shown twice (result: ugly stutter every second). Everything is possible nowadays...
I tend to do conversions myself for this reason. No surprises.
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