Latest post Mon, Nov 28 2016 4:54 PM by nigelad. 5 replies.
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  • Wed, Nov 23 2016 9:16 AM

    • Euchrow
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    Video levels change from one Avid to another

    Hi there,

    I'm editing a feature film, shot on Alexa and transcoded to DNxHD115 in Resolve. REC709 Lut applied in the Source Settings.

    I'm working on a 5K iMac at my studio (BMD Ultrastudio mini monitor) but I also have a copy of the rushes at my home studio (Retina MBPro, BMD Shuttle). Avid 8.6.4, latest BMD drivers, same OSX version.

    I recently discovered that inside Avid, the video level of the footage on my MBpro is slightly brighter than on my iMac. This seems very weird to me as I'm working in exactly the same project (synced through Dropbox) with exactly the same rushes (mirrored disk). It's very annoying since renders done on one machine won't match with the footage on the other machine.

    Included you'll find a screenshot. As you can see on the waveform, the black level on the MBPro is higher than on the iMac. Any ideas how this is possible or how this can be solved?

    Thanks

     

     

     


    Symphony 2019.6 on Mac Pro Westmere 3.33Ghz 6 core, 48Gb Ram, Nvidia GTX 980, High Sierra 10.13.6, BMD Ultra Monitor 2019.6 on MacBook Pro Retina 2018... [view my complete system specs]
  • Wed, Nov 23 2016 9:40 AM In reply to

    • Euchrow
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    Re: Video levels change from one Avid to another

    Actually, the iMac was still on 8.6.1. Updating to 8.6.4 solved the difference in luminance (it's brighter now).

    The question remains which version is bugged: is 8.6.1 too dark or 8.6.4 too bright... 

     

    Symphony 2019.6 on Mac Pro Westmere 3.33Ghz 6 core, 48Gb Ram, Nvidia GTX 980, High Sierra 10.13.6, BMD Ultra Monitor 2019.6 on MacBook Pro Retina 2018... [view my complete system specs]
  • Wed, Nov 23 2016 10:08 AM In reply to

    • Euchrow
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    Re: Video levels change from one Avid to another

    OK Solved !

    There's a bug in the handling of LUT's which was solved in 8.6.2. Without any applied LUT, the levels on both versions are the same

     

    Bug Number: MCCET-1312. Before Media Composer 8.5, imported LUTs (those installed by you from the “Color Management Settings”) considered the LUT domain 0 to 1.0 as full range (0-1023). This should not have been like this since Media Composer has a black and white point at video levels (64-940). This was fixed in 8.5.

    However, this created a problem (in 8.5) for installed LUTS (the ones we ship Media Composer with such as “Sony Slog3 to 709”) where you needed to add a scaling from “Full Range to video levels” before the LUT in order to get the same result as in 8.4.5. This was fixed in 8.6.2.

     

     

    Symphony 2019.6 on Mac Pro Westmere 3.33Ghz 6 core, 48Gb Ram, Nvidia GTX 980, High Sierra 10.13.6, BMD Ultra Monitor 2019.6 on MacBook Pro Retina 2018... [view my complete system specs]
  • Fri, Nov 25 2016 2:50 PM In reply to

    • nigelad
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    Re: Video levels change from one Avid to another

    Thanks for this Euchrow.

    We're haven

    We are using v8.6.1 and have found that levels display wrongly in most players - QT, VLC, Mpegstreamclip etc. These apps appear to assume video levels and scale up to full range automatically, resulting in lost PLUGE [20 and 25 merged with 0,8, and 16].

    Changing source settings to scale from full to video levels [as recommended in the bug fix] before export fixes this problem, so player apps show what we see in MC.

    The only downside is that linking to these exported files back in MC they look wrong [black at 32], unless you set the monitors to "REC709 Full range".

    ISIS 5500, MC 18.12.7 & PT 18.12 on Mac OS 10.12.6 & 10.13.6 with BMD Mini-Monitors, UltraStudio 4K and AJA T-taps. [view my complete system specs]
  • Fri, Nov 25 2016 3:10 PM In reply to

    • Euchrow
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    Re: Video levels change from one Avid to another

    Hi there Nigel,

     

    You can probably solve your export issues by exporting with the 'Keep as legal Range' setting enabled. Exported Same As Source QT's play back in legal range with those players. The thing is that if you convert them to MP4 (using Compressor. Adobe Media Encoder etc), levels are still scaled to full range.

    Full range looks better anyway, so it's no big deal for me for viewing purposes.

     

     

    Symphony 2019.6 on Mac Pro Westmere 3.33Ghz 6 core, 48Gb Ram, Nvidia GTX 980, High Sierra 10.13.6, BMD Ultra Monitor 2019.6 on MacBook Pro Retina 2018... [view my complete system specs]
  • Mon, Nov 28 2016 4:54 PM In reply to

    • nigelad
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    Re: Video levels change from one Avid to another

    Thanks.

    I'm actually using "Keep as Legal Range" settings in all exports and still see this problem. I just tried a Same as Source export but that doesn't fix it either.

    Try it yourself using the Avid "SMPTE_Bars219-2002" or the Belle Nuit chart. The exports seem to be scaled automatically by VLC and QT Player v7 & v10, crushing the blacks.

    But if I create the movie in Premier using the same files, and export a .mov, the levels check out fine in VLC/QT

    What is MC doing differently in it's exports?

    Nigel

     

    ISIS 5500, MC 18.12.7 & PT 18.12 on Mac OS 10.12.6 & 10.13.6 with BMD Mini-Monitors, UltraStudio 4K and AJA T-taps. [view my complete system specs]
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