Latest post Thu, Oct 13 2016 9:12 AM by insch. 13 replies.
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  • Sat, Sep 10 2016 11:04 AM

    • insch
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    choppy playback - I'm a bit lost

    I am preparing some sequences for projection on a large screen at an important event next week. I am having some problems with some of the footage. I just can't get to the bottom of the issue or work out a solution.

    I am working with some progressive 1920 x 1080 YUV footage shot from a helicopter. I have imported it into MC at DNxHD 444 365 X (1080p) RGB. I have colour graded and then exported the sequences in a proprietary format DXV https://resolume.com/software/codec for the video playback software I’ll be using on the night.

    Some of the movement in the original footage is a little choppy - I guess that's progressive filming with objects moving through frame. But when I watch some of the finished sequences played out from my MacBook Pro (on a Sony TV) at times it looks pretty bad. This is not a general playback issue and is certainly not across all my sequences. It's a brand new top spec MacBook Pro so it's not struggling.

    I've carefully gone through the chain but can't quite find out what's going on and where. Occasionally the original rushes will playback really unstably through QT Player (with different frames flashing up during playback) but that's rare. Related? I don't know.

    I'm really concerned about how this is going to look on a very large screen but don't know what to do about it.

    When I play the sequences on my Mac Pro connected to a large 4K screen or fullscreen on my MacBook Pro things look better. The worst results are on my Sony TV connected to my laptop via HDMI - that's the closest I can get to simualting what will happen next week. But that screen will be a lot bigger.

    Is this something to do with interlacing and progressive?

    I'm at a bit of a loss. Can anyone help?

    Thank you : )

     

    Mac Pro, 3.7 GHz Quad-core, 32GB RAM, G-Tech G-RAID Studio etc. [view my complete system specs]
  • Sat, Sep 10 2016 11:36 PM In reply to

    • hbrock
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    Re: choppy playback - I'm a bit lost

    You need more horsepower than your laptop has.  To quote your link to the DXV page:

    With the DXV 3 Codec you can mix more video layers on a higher resolution than any other codec. How? By doing all the hard work on the hardware that does it best: the video card.

    The graphics card in your laptop isn't as powerful as the one in the Mac Pro.  You didn't state the data rate or the source, but a spinning hard disk is much slower than flash memory.

    Also, without knowing what format the original footage was shot in, using DNxHD 444 365x might have been overkill.  Was the color sampled at 4:4:4 or 4:2:2?  Was the aquisition fomat compressed or of a lower data rate?  Was the aquisition using 601/709 or RGB color space?  Was there any change in the frame rate between aquisition and playback?  All of these things matter.  

    Yes, you can deliver frieght in a Ferrari, but the speed of the car doesn't make up for the capacity of a truck.  I'd suggest making a ProRes version and see how that performs for starters.  That will eliminate some of the variables and possibly help you discover where the problem(s) are.

    Of course, if you want more help, give us some more details in regards to aquisition format, sequence formate, etc.

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  • Sun, Sep 11 2016 10:35 AM In reply to

    • insch
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    Re: choppy playback - I'm a bit lost

    Thank you for your time - I really apprecaite your help on this.

    I spent yesterday on this problem and I think the issue might be that I was viewing this material on a Sony TV that was probably trying to turn progressive material into interlaced. I might be wrong but all my tests yesterday showed that the material was basically fine on the laptop screen and my 4K monitor attcahed to my Mac Pro. I am running one stream of DXV (apart from a few seconds here and there when there is a mix between two streams) and the MacBook Pro spec is up to the job according to Resolume. It's a top of the range brand new model with the top spec graphics card.

    Although I can see some minor choppiness on this footage (due to progressive material with movement) the really nasty look this material had the other day I think was due to what the TV was doing to it. Everything within the computer domain seems to be behaving normally. All my material is progressive but I just think the interlace issue (if that's what it was) showed up more on this aerial imagery. I have a lot of other rushes that were originally shot in 4K or 2K and they all look fine.

    The aerial material in question was shot on HDCam SR, I think in 444. I received the shots as files and I have copied the MediaInfo about them below.

    I hope I've got to the bottom of this but don't want any nasty surprises on the night!

    Thanks again : )

    General
    Complete name                            : /Volumes/G-RAID Studio/HD 594-2.mov
    Format                                   : QuickTime
    Format/Info                              : Original Apple specifications
    File size                                : 55.3 GiB
    Duration                                 : 9mn 32s
    Overall bit rate                         : 830 Mbps
    Encoded date                             : UTC 2008-12-23 11:05:01
    Tagged date                              : UTC 2008-12-23 11:15:32
    Writing library                          : Apple QuickTime
    Media/UUID                               : F8EE18BA-9CE2-4577-87ED-F84A41EEC5B8

    Video
    ID                                       : 1
    Format                                   : YUV
    Codec ID                                 : 2vuy
    Duration                                 : 9mn 32s
    Source duration                          : 9mn 32s
    Source_Duration_FirstFrame               : 20ms
    Bit rate mode                            : Constant
    Bit rate                                 : 829 Mbps
    Width                                    : 1 920 pixels
    Clean aperture width                     : 1 888 pixels
    Height                                   : 1 080 pixels
    Clean aperture height                    : 1 062 pixels
    Display aspect ratio                     : 16:9
    Clean aperture display aspect ratio      : 16:9
    Frame rate mode                          : Constant
    Frame rate                               : 25.000 fps
    Color space                              : YUV
    Chroma subsampling                       : 4:2:2
    Scan type                                : Interlaced
    Scan type, store method                  : Interleaved fields
    Scan order                               : Top Field First
    Compression mode                         : Lossless
    Bits/(Pixel*Frame)                       : 16.000
    Stream size                              : 55.3 GiB (100%)
    Source stream size                       : 55.3 GiB (100%)
    Language                                 : English
    Encoded date                             : UTC 2008-12-23 11:15:32
    Tagged date                              : UTC 2008-12-23 11:15:32
    Color primaries                          : BT.709
    Transfer characteristics                 : BT.709
    Matrix coefficients                      : BT.709

    Other
    ID                                       : 2
    Type                                     : Time code
    Format                                   : QuickTime TC
    Duration                                 : 9mn 32s
    Time code of first frame                 : 15:39:40:05
    Time code, striped                       : Yes
    Title                                    : HD 594
    Language                                 : English
    Encoded date                             : UTC 2008-12-23 11:15:32
    Tagged date                              : UTC 2008-12-23 11:15:32

    Mac Pro, 3.7 GHz Quad-core, 32GB RAM, G-Tech G-RAID Studio etc. [view my complete system specs]
  • Tue, Sep 13 2016 5:05 AM In reply to

    • hbrock
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    Re: choppy playback - I'm a bit lost

    insch:
    Scan type                                : Interlaced
    Scan type, store method                  : Interleaved fields
    Scan order                               : Top Field First

    Looks like your original material was interlaced.  If you put that in a progressive project both fields will be put together to make 2 progressive frames as opposed to 2 different fields.  That can cause the material to look choppy on a interlaced display.  The opposite is true for a progressive display where you'll get interlace artifacts when you try to display interlaced media on a progressive display.

    Try this: do whatever you've done so far but do so in a interlaced project.  I'll bet it looks better on a interlaced monitor.  Also, progressive material won't look "worse" on a interlaced display.  

    Ultimately, you should work backwards from your final display format.  If it's interlaced, keep it interlaced.  If it's progressive, de-interlace and stay in a progressive project.  When you've got motion that was captured interlaced, more fields are always better than fewer progressive frames.

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  • Sun, Sep 18 2016 8:09 PM In reply to

    • insch
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    Re: choppy playback - I'm a bit lost

    Thank you and sorry for my slow response - had a big event last week. I am almost certain this material is progressive. What did you see that made you feel it was interlaced?

    Mac Pro, 3.7 GHz Quad-core, 32GB RAM, G-Tech G-RAID Studio etc. [view my complete system specs]
  • Sun, Sep 18 2016 9:57 PM In reply to

    • jef
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    Re: choppy playback - I'm a bit lost

    Jumping in here. I believe the reason the other poster suspects interlace is because the Media Info report you posted states that it is:

    Scan type                                : Interlaced
    Scan type, store method                  : Interleaved fields
    Scan order                               : Top Field First

     

    Good luck,

    Jef

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  • Wed, Sep 21 2016 5:13 PM In reply to

    • Dale Gagne
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    Re: choppy playback - I'm a bit lost

    Thought i would add to this subject line. I was running v8.6.3 and on smaller timelines playback has been no issue however running my first setup of a full 1 hr timeline and suddenly getting choppy playback. Went back to v8.6.1 and issue is gone. Should have been no issue for playback. Been using the same media and setup for series offline editing for 4 years on the same system. Will wait and try again when v8.6.4 comes out.

     

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  • Wed, Sep 21 2016 7:28 PM In reply to

    Re: choppy playback - I'm a bit lost

    Did you try changing the memory settings under the Media Cache settings?

    Note a higher cache value may make playback worse not better. It needs some experimentation.

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  • Wed, Sep 21 2016 7:39 PM In reply to

    • Dale Gagne
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    Re: choppy playback - I'm a bit lost

    I'll give it a try. I was set to 20 gig of cache of my 47 available but I'll set it back to low default and see if that makes a difference.

    Thanks.

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  • Wed, Sep 21 2016 7:51 PM In reply to

    • insch
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    Re: choppy playback - I'm a bit lost

    Thanks Jef

    I'm confused - I am convinced that this material was originally progressive but maybe the files I am working with (which are not the originals) have been converted to interlaced along the way. Not sure why. More invetigation, methinks.

    Mac Pro, 3.7 GHz Quad-core, 32GB RAM, G-Tech G-RAID Studio etc. [view my complete system specs]
  • Wed, Sep 21 2016 8:03 PM In reply to

    • Dale Gagne
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    Re: choppy playback - I'm a bit lost

    same result when setting default lower cache limit. Seems to be something different in v8.6.3 causing this problem as v8.6.1 has no issue...rolling back again.

    Avid MC 2018.10, Avid Mojo DX, Mac Pro, Mid 2012, 2x2.4 ghz 6 CORE Intel Xeon, 64GB Ram, SSD Startup, 10.12.6, ATI Radeon HD 5770, 9TB Internal Storage... [view my complete system specs]
  • Fri, Sep 23 2016 4:25 AM In reply to

    • hbrock
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    Re: choppy playback - I'm a bit lost

    If you want to confirm that the material is indeed interlaced, open the clip in a interlaced project and map some keys from the command palette to allow you to step forward and backward one field at a time.  If you see a change between fields when looking at any motion, it's interlaced.  If you don't see any difference, you might have progressive material that was transferred to a interlaced format (but those won't stutter when played back in a progressive environment).

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  • Mon, Sep 26 2016 8:13 AM In reply to

    • insch
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    Re: choppy playback - I'm a bit lost

    Thank you - that was really helpful advice. Sorry for my slow reply - been rather busy this end.

    I have now checked this footage in a new interlaced project. When I step forward in fields there is no change between field 1 and field 2. So it does appear after all to be progressive footage.

    So it is strange that it is coming up as interlaced in MediaInfo. The key issue now is whether this conversion process somewhere along the line will affect the footage in any detrimental way. Do I need to get all the footage (and there is a lot of it) re-exported as progressive? What would an interlaced export do to progressive footage?

    Thanks again for your help on this.

    Mac Pro, 3.7 GHz Quad-core, 32GB RAM, G-Tech G-RAID Studio etc. [view my complete system specs]
  • Thu, Oct 13 2016 9:12 AM In reply to

    • insch
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    Re: choppy playback - I'm a bit lost

    A bit of an update on this. My observations with the footage in an interlaced project were actually inconculsive - some of the material appeared to be interlaced with movement between fields but on other shots there appeared only to be a vertical shift between field 1 and 2, with no actual change in motion bewteen the fields. But all the material originated from 25P 4444 footage that was captured as ProRes HQ 422. I don't know why that would affect the scanning.

    And the thing that is really doing my head in is the fact that this playback issue is intermittent - sometimes the sequences play back fine and at other times I get choppy playback. This is not a straightforward issue with my video playback software since the problem only occurs with these rushes.

    Can anyone make sense of this?

    Thank you.

    Mac Pro, 3.7 GHz Quad-core, 32GB RAM, G-Tech G-RAID Studio etc. [view my complete system specs]
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