editing Editing Video and Bitrate

[Necrovarius]

Hey all,

I have a question of something that doesnt make much sense.

Ill try to make this easy to understand, if I confuse anyone let me know.

I have had a pet project for a few years. It is a full roleplay of Oblivion. So essentially a gameplay video. My previous recordings were huge! and recorded at like 30Mbps. Even with that bitrate though, it was artifacting, and was not clear when foliage was around the screen.

So i upped my game and got a recording/Streaming PC. I told the software to record at Lossless quality. It looks amazing, and its less Mbps bitrate!

 

Here is where it gets weird. I went to edit it recently. The file that was 30Mbps was easy to edit, playback was smooth and responsive. However when I went to edit the lossless video at the lower bitrate, My editing preview (Sony Vegas Pro) stutters non stop. It is not the video, it is the playback. 

 

Why would this do this?

[WereCatf]

9 minutes ago, Necrovarius said:

Why would this do this?

What codec and framerate were you using  before and now?

[Necrovarius]

Originally I was recording in x264, using CRF of 18.

 

Now I am recording in Lossless Quality, but dunno what codec that is. I am not at my normal computer, so I cant look it up.

Edited October 6, 2019 by Necrovarius
Got something wrong

[WereCatf]

6 minutes ago, Necrovarius said:

Originally I was recording in x264, using CRF of 18.

 

Now I am recording in Lossless Quality, but dunno what codec that is. I am not at my normal computer, so I cant look it up.

Vegas Pro was most likely using your GPU to help with video-rendering when you were using CRF, but now that you're using lossless, your GPU may not support it and so Vegas has to do everything without the GPU's help.

 

What GPU do you have?

[Necrovarius]

5 minutes ago, WereCatf said:

Vegas Pro was most likely using your GPU to help with video-rendering when you were using CRF, but now that you're using lossless, your GPU may not support it and so Vegas has to do everything without the GPU's help.

 

What GPU do you have?

Lemme step back a second, when recording lossless i am using a second PC that captures with an Avermedia Capture card. 

i have turned on GPU Assistance with Vegas to help the Preview Windows stutter and it kinds helps. I am not editing on the machine I recorded with.

 

GPU in editing Machine is GTX1660ti

[mariushm]

t depends on what "lossless" actually means.

It can be lossless "for real" or "practically" lossless.

 

In order to get "real" lossless, x264 has to save h264 streams using High 4:4:4 Predictive Profile and Level 5.1 or higher , depending on resolution and framerate.

Most hardware decoders don't support High 4:4:4, they stop at 4:2:2 or 4:2:0 and Level 4.2 or something like that

Here's a sample video (attached below) I just recorded with OBS with lossless (if you're using Firefox you may see video can't be played because file is corrupt - that's the cisco h264 decoder plugin not supporting High444 Predictive, or maybe it complains because the integrated intel video card in this laptop doesn't hardware decode High444, not sure) :

 

You can replicate this in OBS with x264 using these settings in the custom parameters :

The -qp 0 tells the  x264 encoder to do lossless and overrides the CRF above, and overrides the tune

The cpu usage preset doesn't matter, unless you want to reduce disk space used. x264 will do lossless, higher presets will only give it more cpu to analyze frames and shrink the frames more on your drive. It's like fast vs slow in Winrar or 7zip ... no loss, but can vary disk space.

--profile high444 is kinda redundant because it's added automatically by --qp 0

 

 

 

if you want practically lossless, change to --profile high (or remove it) and ideally you'd use qp 1..5 or something like that. But it seems there's a bug in OBS and that won't work.

So you can remove --qp from the custom options, and use CRF 1 or really anything under 5 would be practically lossless, not visible to human eyes.  It's like spotting differences between saving in JPG at 99% quality and 98% quality.

As it's not lossess and stuff gets thrown away, you also have to change from ultrafast to something that won't cause too much quality loss. The superfast profile should be enough .. the very fast just adds a bit better motion search and lookahead... but since you save at such low crf those won't affect quality much

 

The second video attached is a sample with CR 1 and the above parameters .

 

As for the tune parameter, it can matter in this "lossy" mode. Change stillimage to none or film (for games with cutscenes and movie like) or animation for games like borderlands or games with lots of contrast and edges and crap... stillimage tune could be useful for platformer games, pixel art games, isometric, games with lots of sprites etc

 

 

      --profile <string>      Force the limits of an H.264 profile
                                  Overrides all settings.
                                  - baseline:
                                    --no-8x8dct --bframes 0 --no-cabac
                                    --cqm flat --weightp 0
                                    No interlaced.
                                    No lossless.
                                  - main:
                                    --no-8x8dct --cqm flat
                                    No lossless.
                                  - high:
                                    No lossless.
                                  - high10:
                                    No lossless.
                                    Support for bit depth 8-10.
                                  - high422:
                                    No lossless.
                                    Support for bit depth 8-10.
                                    Support for 4:2:0/4:2:2 chroma subsampling.
                                  - high444:
                                    Support for bit depth 8-10.
                                    Support for 4:2:0/4:2:2/4:4:4 chroma subsampling.
                                    
Ratecontrol:

  -q, --qp <integer>          Force constant QP (0-69, 0=lossless)
  -B, --bitrate <integer>     Set bitrate (kbit/s)
      --crf <float>           Quality-based VBR (0-51) [23.0]

 

[Necrovarius]

Holy Wow @mariushm, here I thought I knew most of what there was to know, but I was wrong. I think the setting I was using was a preset for lossless quality, but I will definitely look into this way instead.