Latest post Sat, Jun 24 2017 8:40 PM by S.Clements. 25 replies.
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  • Thu, Jun 22 2017 10:32 AM In reply to

    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    Ok, its not perfect! But Resolve took two years after Avid MC to fix the incorrect mapping of ProRes444.

    From Arri website:

    Why is ProRes always set to legal range?

    Apple specifies that ProRes should be legal range. Our tests have shown that an extended range ProRes file can result in clipping in some Apple programs. However, the difference between legal and extended coding are essentially academic, and will not have any effect on any real world images. An image encoded in 10 bit legal range has a code value range from 64 to 940 (876 code values), and a 10 bit extended range signal has a code value range from 4 to 1019 (1015 code values). Contrary to popular belief, extended range encoding does not provide a higher dynamic range. It is only the quantization (the number of lightness steps between the darkest and brightest image parts) that is increased by a marginal amount (about 0.2 bits).

    Symphony 7.06 OS 10.9.5 QT 7.6.3 Mac Pro 2x2.66 6-core 32GB Ram Aja Kona Lhi. MC 7.0.6 OS 10.9.5 Mac Pro 5.1 2x2.97 6-core 32GB ram Aja I/O express, Apple... [view my complete system specs]
  • Thu, Jun 22 2017 10:38 AM In reply to

    • S.Clements
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    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    Wow.  Thanks!  You helped me so much!  I was really pulling my hair out over this one.  There are gotchas at every corner in this field.

    Avid Media Composer 8.3.1 Macbook Pro (Retina, 15-inch, Mid 2014) 2.8 GHz Intel Core i7, 16GB Ram Mac, OS 10.10.2 [view my complete system specs]
  • Thu, Jun 22 2017 10:42 AM In reply to

    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    David Yardley:

    Ok, its not perfect! But Resolve took two years after Avid MC to fix the incorrect mapping of ProRes444.

    From Arri website:

    Why is ProRes always set to legal range?

    Apple specifies that ProRes should be legal range. Our tests have shown that an extended range ProRes file can result in clipping in some Apple programs. However, the difference between legal and extended coding are essentially academic, and will not have any effect on any real world images. An image encoded in 10 bit legal range has a code value range from 64 to 940 (876 code values), and a 10 bit extended range signal has a code value range from 4 to 1019 (1015 code values). Contrary to popular belief, extended range encoding does not provide a higher dynamic range. It is only the quantization (the number of lightness steps between the darkest and brightest image parts) that is increased by a marginal amount (about 0.2 bits).

     

     

    I don't think they can really claimthat the difference btween legal (studio) and full range signals is academic. Even in 10 bit we are using all sorts of tricks to expand the usable bit range (log -C etc)

    It seems that Arri are saying Apple expects Prores to be legal (studio) range and its not safe to go outside that (for Apple products) so Arri have decided to stay with Legal range.

    The slightly odd thing with that is the rest of the world seems to have a lot of full swing Prores files in it!

    Still can't understand why MC thinks it needs to add a Studio to Full color adapter?

     

     

    ACI Moderator. I'm not employed by Avid or work for them. I just do this in my spare time. Normally using the current Media Composer version on My... [view my complete system specs]

     

    Broadcast & Post Production Consultant / Trainer  VET

     

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  • Thu, Jun 22 2017 12:00 PM In reply to

    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    Here's a really easy way to tell definitively how the footage should look:

    Find a clip with blown out hightlight.

    Change the Clip Attribute levels in Resolve from Auto, to Video to Full.

    Does changing to Full "recover" any clipped highlight detail? If it does, then you have video recorded at Full range.

    You really can't trust the numbers in Resolve's scopes, but you can tell if changing to Full "brings back" highlight detail.

    I would not trust how things look on the monitor, unless you know exactly how the monitor window in that particular app displays video vs full levels, you can find yourself making decisions that make the look good in for the peculiarities of that app, but maybe not for others.

    Be sure you get the input levels right, as there is a definite right or wrong for that.

    Hope that helps!

     

     

    "When I spent 60k on a discreet edit digisuite system 10 years ago someone came up to me to offer fcp 2, I said it was a scam too." -Ric

  • Thu, Jun 22 2017 12:02 PM In reply to

    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    Pat Horridge:

    I don't think they can really claimthat the difference btween legal (studio) and full range signals is academic. Even in 10 bit we are using all sorts of tricks to expand the usable bit range (log -C etc)

    It seems that Arri are saying Apple expects Prores to be legal (studio) range and its not safe to go outside that (for Apple products) so Arri have decided to stay with Legal range.

    The slightly odd thing with that is the rest of the world seems to have a lot of full swing Prores files in it!

    Still can't understand why MC thinks it needs to add a Studio to Full color adapter?

     

    But Log-C actually does something useful, while adding a few more increments to a ten bit linear scale doesn't.

    "When I spent 60k on a discreet edit digisuite system 10 years ago someone came up to me to offer fcp 2, I said it was a scam too." -Ric

  • Thu, Jun 22 2017 12:32 PM In reply to

    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    S.Clements:

    David Yardley:

    Arri stuff is definitely Studio/video swing, (They give the reason that many softwares interpret it wrongly so they err on safety) so you just need the ArriLogC lut in MC for it to be "as intended."

    Trust Media Composer over the feebie stuff :)

     

    But, it appears that in this case, Avid has guessed wrong about how the Arri material is supposed to be treated, by forcing the uneeded color transformation.

     

    But Avid doesn't make the Arri AMA plugin. Arri does. So I susopect they haven't implemented the plugin correctly.

     

    ACI Moderator. I'm not employed by Avid or work for them. I just do this in my spare time. Normally using the current Media Composer version on My... [view my complete system specs]

     

    Broadcast & Post Production Consultant / Trainer  VET

     

    T 07581 201248 | E pat@vet.co.uk | W www.vet.co.uk |


    Media Composer V8.2 Review Background Render

    -

    Follow me on Twitter Pat_H_VET

  • Thu, Jun 22 2017 3:02 PM In reply to

    • S.Clements
    • Top 150 Contributor
    • Joined on Sun, Jul 3 2011
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    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    BobbyMurcerFan:

    Here's a really easy way to tell definitively how the footage should look:

    Find a clip with blown out hightlight.

    Change the Clip Attribute levels in Resolve from Auto, to Video to Full.

    Does changing to Full "recover" any clipped highlight detail? If it does, then you have video recorded at Full range.

    You really can't trust the numbers in Resolve's scopes, but you can tell if changing to Full "brings back" highlight detail.

    I would not trust how things look on the monitor, unless you know exactly how the monitor window in that particular app displays video vs full levels, you can find yourself making decisions that make the look good in for the peculiarities of that app, but maybe not for others.

    Be sure you get the input levels right, as there is a definite right or wrong for that.

    Hope that helps!

     

     

     

    Thanks, Bobby.  Unless I'm missing something, is the only way to test for this to switch from Auto to Video to Full on three separate exports, and then bring all the clips back into Resolve and check that way?  It doesn't appear as though you can toggle between the results in the program.

     

    Avid Media Composer 8.3.1 Macbook Pro (Retina, 15-inch, Mid 2014) 2.8 GHz Intel Core i7, 16GB Ram Mac, OS 10.10.2 [view my complete system specs]
  • Thu, Jun 22 2017 3:07 PM In reply to

    • S.Clements
    • Top 150 Contributor
    • Joined on Sun, Jul 3 2011
    • London, United Kingdom
    • Posts 812
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    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    Thanks for all the help, everyone.  I'm very glad I got the opportunity to finally try out this workflow as it is a very popular one for making dailies.  The advantages appear to be the ease of making timecode and file name burn-ins on separate MXF clips, as well as filling the Tape column with the file name.  On top of it, people like this workflow so they can use free software on unused machines to do transcoding.  It is a pain in some ways, but I can see the advantages.

    Avid Media Composer 8.3.1 Macbook Pro (Retina, 15-inch, Mid 2014) 2.8 GHz Intel Core i7, 16GB Ram Mac, OS 10.10.2 [view my complete system specs]
  • Thu, Jun 22 2017 4:57 PM In reply to

    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    S.Clements:

    BobbyMurcerFan:

    Here's a really easy way to tell definitively how the footage should look:

    Find a clip with blown out hightlight.

    Change the Clip Attribute levels in Resolve from Auto, to Video to Full.

    Does changing to Full "recover" any clipped highlight detail? If it does, then you have video recorded at Full range.

    You really can't trust the numbers in Resolve's scopes, but you can tell if changing to Full "brings back" highlight detail.

    I would not trust how things look on the monitor, unless you know exactly how the monitor window in that particular app displays video vs full levels, you can find yourself making decisions that make the look good in for the peculiarities of that app, but maybe not for others.

    Be sure you get the input levels right, as there is a definite right or wrong for that.

    Hope that helps!

     

     

     

    Thanks, Bobby.  Unless I'm missing something, is the only way to test for this to switch from Auto to Video to Full on three separate exports, and then bring all the clips back into Resolve and check that way?  It doesn't appear as though you can toggle between the results in the program.

     

    I think *I* may be missing something, lol! Can't you just just change the clip attributes on the Media Page in Resolve and look at the scopes? I don't see why you need to transcode at all for this test.

     

    "When I spent 60k on a discreet edit digisuite system 10 years ago someone came up to me to offer fcp 2, I said it was a scam too." -Ric

  • Thu, Jun 22 2017 5:03 PM In reply to

    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    Pat Horridge:

    S.Clements:

    David Yardley:

    Arri stuff is definitely Studio/video swing, (They give the reason that many softwares interpret it wrongly so they err on safety) so you just need the ArriLogC lut in MC for it to be "as intended."

    Trust Media Composer over the feebie stuff :)

     

    But, it appears that in this case, Avid has guessed wrong about how the Arri material is supposed to be treated, by forcing the uneeded color transformation.

     

    But Avid doesn't make the Arri AMA plugin. Arri does. So I susopect they haven't implemented the plugin correctly.

     

     

     

    Pat, It does seem odd. I wonder if Arri did that so the files look "right" in MC's viewers displaying full levels. 

     

    "When I spent 60k on a discreet edit digisuite system 10 years ago someone came up to me to offer fcp 2, I said it was a scam too." -Ric

  • Sat, Jun 24 2017 8:40 PM In reply to

    • S.Clements
    • Top 150 Contributor
    • Joined on Sun, Jul 3 2011
    • London, United Kingdom
    • Posts 812
    • Points 10,765

    Re: Difference between Avid and Resolve Transcodes of same Arri ProRes 4444 QTs

    I did some more experimenting, but I must admit, it's all doing my head in.  Amazingly, this happens too:

    If I remove the "Levels scaling (video levels to full range)" color transformation from the AMA-linked ProRes 4444 clip and still keep the rec 709 Lut applied....

    And then render out a flat transcode from Resolve, with no LUT applied and bring it into Avid...

    I can only get the flat transcode to match the AMA clip, if I change it's source settings to add the rec 709 Lut and then the "Levels scaling (full range to video levels)"

    But, if I just bring in the AMA and the flat resolve transcode and then just apply the rec 709 LUT, they look different

    And this is the kicker....I can get the flat resolve transcode to match the AMA-linked defaults (of video to full, followed by rec 709) if I change its source settings to this: Levels scaling (video levels to full range), then I add the rec 709 LUT, then I add Levels scaling (full range to video levels).  That's 3 separate transformations.  

    Weird.  I don't really know what all this means.  I am thinking of rendering out flat Resolve Transcodes as an emergency backup.  I find it totally bizarre that Arri's AMA plugin would be faulty after all these years and no one would bring it to their attention that they are adding an unecessary color transformation.

    Avid Media Composer 8.3.1 Macbook Pro (Retina, 15-inch, Mid 2014) 2.8 GHz Intel Core i7, 16GB Ram Mac, OS 10.10.2 [view my complete system specs]
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