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GH2 and the BMD HyperDeck Shuttle Record Problems

Aug 13, 2012 7:10 AM

Tags: #black_magic_design_shuttle #black_magic_design_shuttle_2 #gh2_hdmi_recording #clip_repair

Hello All :-)

 

I have a BMD HyperDeck Shuttle 2 and it records uncompressed and in the DNxHD (220) codec.

 

I can import, play and edit the files just fine, but there's a major problem that makes the files useless.

 

Static scenes are fine except they are flat and require color correction to make them aesthetically acceptable. 

 

The main problem is that the files have horrible interlacing problems... and I'll explain.

 

First of all, it doesn't matter whether I shoot in FSH, HBR, 24p or don't hit the camera record button at all and just record from the cleaned display... the same problem occurs, so it isn't a camera setting (I've spent 2 days experimenting with different cam settings as well).

 

When panning I get fine interlacing lines.  They are annoying and unacceptable in their own right, but it gets worst.  Once encoded (as in for distribution) the problem is accentuated.  Huge lines appear and and make the video look horrible... it is unusable.

 

On close inspection of the files in PP CS6 I can see that the file is filled with ghost images, which I thought were a result of duplicate frames that the GH2 has served to the BMD Shuttle 2.

 

I've read about certain fixes for this and a the color shift issues, but  a) most sound too difficult to be used in a practical workflow and at the end of the day, they may not even work.

 

So I'm here with hat in hand hoping that a discussion might yield some fruit that can help me, and others that are having the same problem or looking to use a Shuttle with their GH2s.

 

-------

 

Update...

 

I said that extra frames were being added, well I read that recording from the GH2's HDMI port added and deleted frames randomly, and that clouded my judgment and made me lean in that direction,  but upon closer inspection (I was going to experiment with manually removing the extra frames) I found that there are no extra frames per-say.

 

The ghosting I described is at the heart of the problem.

 

When panning each frame appears to be a combination of 2 frames at different times.  So depending on the speed of the pan (and the shutter speed - the higher the SS the closer together is the dual images) you get an interlaced image (half of the lines) at one point in time, and another (the other half of the lines) at a later point in time. 

 

Where they overlap, the image is solid, but on either side you have a "ghost" image which when played back you can see through the image where the missing lines are, thereby giving a notched edge  effect.

 

And I haven't even wrapped my head around how I can fix that yet??

 

Thanks for your interest and feedback!!

 

AM

 
Replies
  • Currently Being Moderated
    Aug 13, 2012 3:33 PM   in reply to Amarotti

    Two comments.

     

    I believe the GH2 will only output 30i over HDMI, no matter what record settings you choose.  So right there you have an interlaced signal.  This is largely what steered me away from external recorders on the GH2.  That we can hack it and significantly improve the quality of the in-camera recording is another.

     

    Go into PP's playback settings and make sure it's not set to display both fields.  Choose Upper instead.

     
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  • Currently Being Moderated
    Aug 14, 2012 4:35 PM   in reply to Amarotti

    1080i/60 is a common but technically incorrect mehtod of saying 1080i/30.  So we're in agreement about the HDMI output.  You can't get progressive out of the GH2.

     

    The Display Fields option is only for PP, it won' affect exports.

     
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  • Currently Being Moderated
    Aug 14, 2012 7:30 PM   in reply to Amarotti

    Are you editing then exporting from your HD timeline to HD? Or HD to SD? In my experience with cs6 if I edit HD upper field first stuff in a upper field seqeunce that was captured originally from my BMD hyperdeck studio and export it to SD, no matter what field order I use it comes out looking strange.

     

    What I had to start doing to make it look correct was edit my upper field first content in a progressive sequence and export it to progressive.(Only When going from HD to SD though) When I edit it in HD though with the plans to export to HD I don't have to export to progressive nor edit in a progressive sequence to make it appear correct anymore.

     

    Not really sure why it seems to play out this way though, it's just the only way I have been able to make it work. Not sure what your exporting your content as though so I'm not sure if this will apply to your issue or not.

     

    Also when you QC your exported content what media player are you watching it in? Also what field order are you selecting upon export?

     
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  • Currently Being Moderated
    Aug 15, 2012 3:12 PM   in reply to Amarotti

    What field order are your sequence settings you're editing in? What field order are you selecting when you export/send to Adobe Media Encoder? Also are you scaling anything at all?

     
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  • Currently Being Moderated
    Aug 16, 2012 4:25 PM   in reply to Amarotti

    others have said that you can get it back to 24p by using a pull down.

     

    That's sort of correct.  The HDMI port adds additional fields/frames to make the 24p original "fit" into a 30i signal for output.  Premiere Pro understands that type of situation, and can remove the extra frames on the fly simply by working in a 24p sequence.

     
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  • Currently Being Moderated
    Aug 17, 2012 7:29 AM   in reply to Amarotti

    If the HDMI took a 24p signal and added frames, I could underestand that

     

    That is what happens.  That's how you get 30i from 24p, you add things that weren't there to begin with.  It's what DVD and Blu-ray players have always done with film content, which is shot at 24 fps, but needs to be displayed on a TV at 30i.  It's how movies have been broadcast on television for decades.  PP just happens to be smart enough to remove what was added to get back the original 24p.

     

    But that is somewhat moot if you're shooting at 30i to begin with, which should be coming out the HDMI port same as it's being recorded.

     

    Panasonic's comment doesn't surprise me at all.  It's why I went with a hack instead of external recording.  Perhaps the GH3 will be better in this regard and output a proper 4:2:2 signal in the format of choice.

     
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  • Currently Being Moderated
    Aug 22, 2012 11:42 PM   in reply to Amarotti

    Hi guys!

     

    I have no external recorder, so I cannot check it, but there is a solution for extracting a clean 24P from GH2 HDMI captures:

    http://www.dvxuser.com/V6/showthread.php?237584-HDMI-Capture-Problem-S OLVED-AviSynth-RULES!

     

    Ralph B, the author of this solution, described everything in the first post, so you don't have to read through the lengthy thread.

    He also has updated his post (on 03-27-2012) adding section on HDR mode with firmware 1.1.

     

    Asked later on May, whether the HDMI picture is better than the hacked picture, he said:

     

    "There is a difference, but it's subtle. The problem is each person has their own perception of what's acceptable. Mine may not match yours, so there's no way I can say do it or don't do it. The best advice I can give you is to get a hold of an HDMI recording device or capture card, and run your own tests. The good news is you can record simultaneously in-camera and externally, so you can compare the two later."

     

    Hope this helps.

     
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