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Old July 1st, 2006, 02:39 AM   #1
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How accurate is MPEG Streamclip conversion with JVC 720p24?

I have about 7 hours of 720p24 footage (already captured as .m2t files) which I need to convert into AIC .mov files tomorrow.

Back in January I did some conversions of 720p24 footage with MPEG Streamclip Version 1.6, which included a "Frame Rate" box for the first time, and I entered "24" and the conversions were ghastly, with many frames omitted and many repeated. I assumed that MPEG Streamclip could not correctly pull down the 24 frames out of the 60 frame stream (which I believe consists of 24 actual frames and 36 "place markers" - or something like that) and purchased HDVxDV which gives a perfect conversion of the correct 24 frames but has the downside of the audio drifting out of synch because it has no function to fix timecode breaks (which is one of the strengths of MPEG Streamclip).

Before I convert this latest batch with HDVxDV (and therefore consign myself to many future hours of trying to match the sound to the actor's mouths in my final edited sequence) I was wondering if anyone has had much experience converting 720p24 footage from the GY-HD100 with the latest version of MPEG Streamclip (Version 1.7 released on 31 March 2006) and if they can indicate whether it now gives a perfect 24 frame conversion (or not).

I know that one of the added features of Version 1.7 is "full support for 23.976 fps streams with 3:2 pulldown" but I've been led to think that the JVC GY-HD100 is quite unique in how it achieves its pulldown. I'm referring specifically to a post by Mike Curtis on his famous blog http://www.hdforindies.com/ on Tuesday June 27th under the heading "JVC's 24p Pattern Mysteries" where he speaks of it using a 2:2:2:4 pulldown pattern.

So I'm interested in anyone's experiences (positive or otherwise) in converting GY-HD100 720p24 .m2t files with Version 1.7 of MPEG Streamclip.

Thanks.
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Old July 1st, 2006, 05:31 AM   #2
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David,

Since MPEG Streamclip is free, why not upgrade your existing version and try it on a clip. You have nothing to lose and everything to gain.

-gb-
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Old July 1st, 2006, 06:50 AM   #3
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Thanks Greg. I've now started my conversions with HDVxDV, but just did a separate test on a 720p24 clip with MPEG Streamclip and it had many repeat frames.

But the reason I asked my original question was because I've seen recent posts stating the workability of MPEG Streamclip with 24p (e.g. http://www.dvinfo.net/conf/showthread.php?t=67227 ) and was wondering if I'm missing something, or if the guys doing it had really inspected their conversions frame by frame.

As I've given up on Apple providing an HDV720p24 upgrade for FCP before I finish this project, I'll email the creator of MPEG Streamclip and provide him with the exact 24p pulldown sequence of the GY-HD100 and perhaps he'll upgrade it. I'd still like to have an interim solution which gives the correct 24 frames PLUS the audio in sync.

The sequence I'll email is the 2:2:2:4 pulldown (as given by Mike Curtis) which I assume is correct, but if Steve Mullen or any of our many resident experts believe it to be different, feel free to inform me.
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Old July 1st, 2006, 11:24 AM   #4
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David,

I should have mentioned this a month or two ago, but Mpeg Streamclip does actually do a great job of removing pulldown during "export to quicktime."

The nice thing about Mpeg Streamclip is that it has always ignored the repeat frames in the viewer window, so it is very easy for it to ignore them during export as well.

Your problem before was that you used "24" for a frame rate instead of "23.976" Please look at the attached jpeg to see what your settings should look like for good results.

The other really nice thing about Mpeg Streamclip is that if you had accidentally captured over a TC break, you can simply mark an IN or OUT mark (with the "i" or "o" keys) and only export that section.

I think Mpeg Streamclip is definitely the front runner now that it has a universal version. I've used it on my MacBook Pro and it works great.


BTW, you should update Quicktime to 7.1.2 and try using the "Apple HDV 720p30" codec with a 23.976 frame rate. Then create a new 720P30 HDV sequence in FCP5 and change the frame rate to 23.98.
Amazingly it works! The only problem I can see is that the Mpeg has been re-encoded instead of just converted.
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Old July 1st, 2006, 11:33 AM   #5
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How is it with Windoh's?
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Old July 1st, 2006, 11:34 AM   #6
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Originally Posted by Keith Forman
How is it with Windoh's?
If it doesn't crash then it should work the same way. :)
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Old July 1st, 2006, 01:45 PM   #7
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I haven't had any problems with repeat frames when converting 720/24P in MPEG STREAMCLIP. I transcoded to 23.98 AIC. From now on though, maybe I will try the HDV 30 with the 24 Frame Timebase.
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Old July 1st, 2006, 02:10 PM   #8
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avid codecs missing

I installed Mpeg Streamclip, and had to install Quicktime Alternative, but now I've lost the avid codecs (I'm a AVXPro user).

Any ideas on how to get them back and still be able to use Quicktime Alternative?
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Old July 1st, 2006, 02:20 PM   #9
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disregard my last post, I just copied the avid codecs in the Quicktime Alternative/QTsystem folder and the avid codecs are back in business!
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Old July 1st, 2006, 05:24 PM   #10
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I just used MPEGStreamclip to convert a bunch of clips and I really liked the batch mode. Another nice feature of this remarkable software.
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Old July 1st, 2006, 07:49 PM   #11
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Quote:
Originally Posted by Tim Dashwood
The only problem I can see is that the Mpeg has been re-encoded instead of just converted.
Have you seen a PQ difference between the recode to AIC and HDV?

In theory, AIC should be easier to edit, being all I frames.

Wonder if FCE 3 will edit 24p AIC if I go Intel?

I'm hearing that the real FCP deal could be fall 2006 (when Avid does it's next release) or even early 2007. But after waiting this long, I no longer want simple 24p support. I want a Sequence that will accept all media -- which is what Avid offers.

I'm sure if I upgrade 5.0.4 to 5.1 -- Apple will require yet another $$$ upgrade to get "real" 24p support. :) Could there a be a reason the Studio Upgrade expires at the end of 2006?
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Last edited by Steve Mullen; July 2nd, 2006 at 04:17 PM.
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Old July 2nd, 2006, 06:24 AM   #12
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Quote:
Originally Posted by Steve Mullen
Could there a be a reason the studio Upgrade expires at the end of 2006?
I have a feeling that this is true.

But I just upgraded to Avid 5.5 for $50. And I'm sure I will have to pay for 24P support in that as well.
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Old July 3rd, 2006, 06:37 AM   #13
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Quote:
Originally Posted by Tim Dashwood
David,

I should have mentioned this a month or two ago, but Mpeg Streamclip does actually do a great job of removing pulldown during "export to quicktime."

The nice thing about Mpeg Streamclip is that it has always ignored the repeat frames in the viewer window, so it is very easy for it to ignore them during export as well.

Your problem before was that you used "24" for a frame rate instead of "23.976" Please look at the attached jpeg to see what your settings should look like for good results.
...

BTW, you should update Quicktime to 7.1.2 and try using the "Apple HDV 720p30" codec with a 23.976 frame rate. Then create a new 720P30 HDV sequence in FCP5 and change the frame rate to 23.98.
Amazingly it works! The only problem I can see is that the Mpeg has been re-encoded instead of just converted.
Thanks Tim. (Yet again.) I was definitely missing something! I just tried it on that same test clip with 23.976 and it worked like a charm.

One of the things I do like about HDVxDV is that it gives you an exact 24 frames. (I'm in a PAL area and only ever have to convert to 25 frames/sec and don't usually have to worry about 29.97 compatibility.) As my edited sequence already is 65 minutes long (without the new footage) and all in an exact 24 frames, I'll adopt the workflow of conversion in MPEG Streamclip at 23.976, then pull the clips into Cinema Tools and conform them to an exact 24 frames, then import into FCP.

Also, thanks for the tip on converting with the Apple HDV 720p30 codec. If you've had a chance to study it out yet, what's your opinion of its quality (as it's been re-encoded) compared to the AIC conversions?

I wonder if it's possible (wishful thinking, but why not?) for conversion software (such as MPEG Streamclip) to simply put a "Quicktime wrapper" around the existing .m2t file (rather than re-encode it). That would give us true native editing and then output the finished sequence as Uncompressed.
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Old July 6th, 2006, 01:31 AM   #14
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What conversion time ratios are you guys seeing when using Mpeg StreamClip for the 24P?

Thanks,

Sam
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