Saturday, January 28, 2017

Re: [Avid-L2] 8K to YouT ube

 

Ok, some progress:

The Premiere plugin is way slower than FFmpeg, totally unusable for normal production work (On this kind of job, to 8k…).
And, besides that, it can only output VP9 to WebM. 
Now, for YouTube a file must be injected with metadata (No clue what that actually does, but without it, YouTube does not see it as a VR clip.)
The app. to inject does not accept WebM. It only wants Mp4 or QT. 

So, since the data rate for me is not that interesting;
 (Youtube will re-transcode always, my transcode is only to get a file fit to upload from my relative slow connection.)
I've tried  FFmpeg VP8 instead. That renders twice as fast as VP9, and produces a 8K file that is accepted by YouTube.
(Render time is now 25 times slower than RT on a 29.97 fps clip, and I can probably speed that up as it's only using 30% CPU.)
Again, this is ONLY the transcode from a 8K Prores file to an 8K in-between to upload!
For those interested, this is the 8K test video


Bouke

Edit 'B / VideoToolShed.com
van Oldenbarneveltstraat 33
6512 AS  Nijmegen
+31 6 21817248

On 27 Jan 2017, at 11:28, Bouke <bouke@editb.nl> wrote:

Steve,
With the GoPro rig, you end up with 6 images of 2.7 K, with a fair amount of overlap.
After the stitch you have an 8K movie.
Now, when you watch it in a 360 player, you have (horizontally) about 100 degrees of viewing angle, that's 8k / (360/100), so roughly 2200 pixels.
That is even less than the screen resolution of a modern smartphone. So yes, in theory I should be able to see the difference between 4 and 8 K, as 4K only has less than half the pixels available on the screen.
(Do note, I have a GearVR viewer, without it it's probably a pointless exercise.)

I have no clue how sharp the image really is. During the stitch, here is a huge amount of warping done on the images to compensate for the poor fisheye lenses.
(Granted, that is done very well, but probably at the cost of sharpness.)

Next, there is a huge amount of color correction. In my test video the main cam was looking towards the sun (just hidden behind a part of the building), so the end result had the main objects close to black.
I take it that adds a lot of noise / garbage as well. (But again, the stitching software does a very decent job considering the huge differences between the cams, and I have not yet found a way to get the source images into Resolve prior to stitching.)

And then, the player scales / warps the image during playback. In RT (It's amazing that a stupid phone can play it back already, but doing an RT DVE is really requiring horsepower, so I take it there is rough rounding as well..)

I very much doubt 8K will be used in real production for my clients (education), as the render times to VP9 are too painful. 
(Way over 4 hours for a 5 min. clip, that's just transcoding from ProRes to VP9, the stitching / rendering itself takes a lot of time as well...)
On the other hand, they have enough bandwidth to upload ProRes (they are a university), and have YouTube do the conversion.

I'll see what the Premiere plugin does next…

Bouke

Edit 'B / VideoToolShed.com
van Oldenbarneveltstraat 33
6512 AS  Nijmegen
+31 6 21817248

On 27 Jan 2017, at 10:18, 'Steve Mullen (DVCinLV)' dvcinlv@gmail.com [Avid-L2] <Avid-L2@yahoogroups.com> wrote:

Google for "WebM_Premiere_v1.0.3


Are the GoPro Omni files really 8K?

I thought they had to be 4:3 and that 2.7K was the largest source files.

But, maybe the stiched image is huge. What are you watch 8K on to see the difference between it an 4K?

Best Regards,
Steve Mullen






__._,_.___

Posted by: Bouke <bouke@editb.nl>
Reply via web post Reply to sender Reply to group Start a New Topic Messages in this topic (11)

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