According to this link Avid DNxHR HQX and DNxHR 444 are 12 bit. The rest are8 bit.
I picked up on a 4K project in a bay with HD Rec709 monitoring. It had already been color corrected and I was just exporting. The delivery wanted high quality 12 bit. The source was Sony Raw from I believe an F55 or maybe an F5. The sources were linked. I kept the project in 709 YCbCr mode and set the project to 4096_2160 format setting the Output Hardware setting to 1920_1080. This all worked but I had to do a video mixdown to DNxHR HQX to be able to watch the sequence down without stuttering etc... This is nothing new I have found in my normal 4K projects I have to render a safe color upper effect to get reliable 10 bit playback.
From this I exported to QT to DNxHR 444 and everything seemed to work fine. As I don't normally deal with super high end files I'm thinking I should have not used the video mixdown track when exporting because it had taken the Sony Raw ama linked clips and created DNxHR HQX media thereby lowering the source quality somewhat. In my mind the difference is small and probably imperceptible to the viewer but for the sake of the most pristine workflow I think I should have exported from below the video mixdown.
Given they wanted 444 for delivery should I have switched the project to a 709 RGB project? I haven't played in the RGB project sandbox other than a couple of tests with the 1-254 ramp avid supplies in the supporting files. In my ramp tests I found the 1-254 ramp showed the proper over and under shoots in all projects except an RGB 709 project with the timeline quality set to green 8 bit. In the green 8 bit mode the over and under shoots in level were clipped at 0 and 700mV. It was strange that toggling to 8 bit quality had an effect on the overall level on my external waveform.
Regardless of that anomaly in this particular case could I take the project that was colored in YCbCr 709 mode and just switch to RGB 709 color space mode and have the levels track? I'm not back at the system I was on to check this out and in the heat of the battle I had no time to experiment. The core of my question is if the Sony Raw F55 footage is ama linked would switching the project to RGB 709 access the source material as 444 and thereby give a more pristine file? By working in my normal project mode of YCbCr 709 am I downgrading the potential quality that could be derived from a Sony Raw ama link. Also where does bit depth play into all these factors. Given DNxHR HQX and DNxHR 444 are listed as 12 bit codecs what is Avid processing ama linked clips in. The timeline only offers 8 and 10 bit quality mode and given I have seen that effect the SDI output in the RGB 709 project does it have any effect when exporting.
I have no doubt that when I did the video mixdown to DNxHR HQX it must somehow reduce the accessible image quality but at that point I think I'm splitting hairs. I suppose there may be some variations when shooting Sony Raw that also might effect image quality potential but I'm not familiar with what options they have in the field. I would think Sony Raw is basically sensor data but is it?
Bottom line should I have switched to and RGB 709 project and exported from the ama link track not the mixdown to maintain the maximum quality I could have?
John Moore Barking Trout Productions Studio City, CA bigfish@pacbell.net
__._,_.___
Posted by: John Moore <bigfish@pacbell.net>
| Reply via web post | • | Reply to sender | • | Reply to group | • | Start a New Topic | • | Messages in this topic (1) |
Have you tried the highest rated email app?
With 4.5 stars in iTunes, the Yahoo Mail app is the highest rated email app on the market. What are you waiting for? Now you can access all your inboxes (Gmail, Outlook, AOL and more) in one place. Never delete an email again with 1000GB of free cloud storage.
this is the Avid-L2
.
__,_._,___
No comments:
Post a Comment