HEVC Export quality

AndyMo wrote on 4/27/2021, 2:32 PM

Hello - for the most part the HEVC codec has been working nice, but i am having some challenges with export quality in a few situations. I am editing 5760x2880 360 video files that were exported from insta360Studio as (h.265, 200Mbps).

Here is a frame from the clip in MEP's preview window (note that the preview window is set to reduced resolution):

You can see some of the features of my face ok.

When I export the move using HEVC with these parameters:

it really struggles with motion and flickering light. You can see here my face is all blocky:

I even tried using I-frames only in the GOP, and it was even worse:

Strangely, I get better quality using the h264 codec, but MEP limits that export to 3840x1920. It's not 'great' quality, but at least it is not large blocks like in the h265/HEVC:

Any hints on how to get HEVC to produce a better output without all the blocky-blotchiness?

Thank you in advance.

Comments

johnebaker wrote on 4/27/2021, 3:02 PM

@AndyMo

. . . . Any hints on how to get HEVC to produce a better output without all the blocky-blotchiness? . . . .

For the video resolution you are exporting to the video bitrate is way too low at 15000.

I tested, starting with the HEVC MP4 UltraHD 3840 x 2160 preset and modified just the resolution and AR settings and saved it as a preset and the playback is much better - see image below.

HTH

John EB

AndyMo wrote on 4/27/2021, 4:13 PM

Thank you John. I tried it out and the resulting image is better. Still some faint blockiness compared to the h264. I am going to try another run using Level 6.0

Interesting that the same preset you selected gave me a VBR of 36500 and not 35000

Scenestealer wrote on 4/27/2021, 5:49 PM

@AndyMo

Hi Andy

If your original footage is truly 200Mbps H.265 then you will surely see compression artifacts if you export at a fraction of the original bitrate even at 35Mbps!

I even tried using I-frames only in the GOP, and it was even worse:

This is not surprising because I frames are much less compressed than the P and B frames which contain all the efficiency of MPEG compression, so you would need to increase the export bitrate about 3x over the original 200Mbps.

Peter

CubeAce wrote on 4/27/2021, 6:21 PM

@Scenestealer @AndyMo

I have to agree with Peter.

I never let my exports have a lower bit rate than the original footage and the exports are very close to the original clips. Unless you have a good reason to lower the resolution, say for use on a Blu-ray disc it make no sense to reduce bit rates.

johnebaker wrote on 4/28/2021, 3:44 AM

@AndyMo

Which Insta camera was used to take the video?

@Scenestealer, @CubeAce

. . . . If your original footage is truly 200Mbps H.265 . . . .

If this is 360° video from an Insta 360 dual sensor/lens camera then the 200mbps would be the sum of the 2 sensors - from some of the camera specs each sensor outputs at up to 100 Mbps.

John EB

AndyMo wrote on 4/28/2021, 10:02 AM

My camera is the Insta360 One X. The app default exports to 135Mbps, but I had it set to 200m during this experimentation.

Thanks to all. I feel a little silly not catching the fact that the VBR rate should be same as the clip rate. I guess I got a little overwhelmed by all the codec options (and mis-led by an article I read on the web). Cranking things up seems to work well - no blocks ! I am going to now try it on my torture test: waving grass underwater!