Question / Help Need more options for Quick Sync Quality for streaming

[ShamisOMally]

Only in the last two weeks I have gotten the ability to use Quick Sync since I bought a 4770K, and I've been playing with the options

What I found is OBS by and by has, lets face it, pretty normal quality for streaming with quick sync, even when using custom settings vs software settings

Recently I looked into using Quick Sync with Mediacoder settings, and I found I got about the same quality as OBS did if I set it to only 1 ref frame and stuck it on the highest quality preset

After setting it to 3 frames, I got a decent quality boost, and 8 frames, got a bit better quality boost

But the biggest boost, by far, was turning on Look Ahead Bit Rate Control, and setting it to 100 to read a frame 100 times before encoding it

The quality I am getting out of this is PHENOMENAL, I have uploaded an example here using 2500bitrate encoded with my haswell using Mediacoder set to 3 ref frames and LA BRC set to 100, most importantly was this in no way exhausted my Intel GPU, it encoded this video at 2.42x its framerate with zero CPU use meaning its more than capable of doing these settings in OBS and not having frame drop

Here is Quick Sync with 3 ref frames set to 2500bitrate with LA BRC set to 100 and 128Kbit AAC audio 1080p

http://www.filedropper.com/quicksyncencoded2500bitrate128kbitla-aacaudio

And here is software encode set to Very fast with 4 reference frames at 2500bitrate with 128Kbit AAC audio

http://www.filedropper.com/sofwareencodeveryfast2500bitrate128kbitla-aacaudio

As you can see, the software encoder set to very fast is vastly inferior, and took a huge CPU hit of 100% to only encode at 1.98x the files framerate

If it would be possible to get settings for more frame references, and even more importantly LA BRC settings into OBS, it would improve quicksync quality dramatically

Thanks for your time

 

[PampaBounce]

Hi ShamisOMally, thanks to you for your comparaison but the link are down.
I had try to use Quick Sync with Mediacoder to reproduce the same results and you are absolutly right, the quality increase a lot !

It will be interesting to see the LA BRC implemented in OBS, i think many people (streamers indeed) will be interested by this solution. At this time, for exemple, transcoding at 4000kbps for twitch with QuickSync in 1080p 30fps is not enough in terms of quality compared to the x264 implementation with veryfast preset. (it's my subjective vision).

Hope more QuickSync options will be more implemented in the future :)
Thanks for reading too.

 

[Jack0r]

You always have to differentiate between functions that can be used during a live encoding where time is important and functions that are meant for the re-encoding of already created video files.
I could not get this software to work and use my QuickSync, it always used horrendous amounts of CPU or simply gave an error. So we will have to see if @Palana did not already check these options and had a reason to not implement them yet.

 

[PampaBounce]

Thanks to you for your answer Jack0r
With options like LA BRC, there will be more delay for the encoding, meaning igpu will require more ram. This is almost the same concept than double pass x264 encoding on a time segment. There will have more desynchronisation with audio but maybe while playing with the audio-delay...
As you said, it's generally different to transcode in real time than encoding a complete file.

I'm gonna looking on the intel sdk and make a correlation with ffmpeg in order to see what are the options.