A quick question about Quick Sync

vbimport

#1

No pun intended :bigsmile:

I’m just curious about a detail. If no VGA is installed in the computer, because the one included in Sandy/Ivy bridge CPUs is used, when all GPU cores are used for encoding purposes, is the computer still usable? I mean is it still possible to watch a clip from youtube for example or using the browser while the machine is busy with video encoding? Even more: is it still possible to watch a movie with VLC for example while the machine is encoding?

I know that quick sync allow to encode a full movie in a matter of minutes (thanks Dee for posting test results :bigsmile:), but what happen if you keep the machine busy for a couple of hours?

Moreover, what happen to quick sync if a discrete VGA is installed? Is it still possible to use the Sandy/Ivy GPU cores for video encoding when a discrete video card is installed?

I almost forgot: I’m referring to a system with Z77 chipset :slight_smile:

Just for comparison, my current system (Intel E8400) allow me to watch a movie with VLC when Handbrake is working without any problem (no stuttering, no pixelation). Handbrake process priority is set as normal, so even if it using the CPU at 100 the machine is still usable.

I have a pretty basic VGA installed in my computer, a nvidia 8500GT, not exactly the most powerful video card available, but is still able to manage VLC playback when handbrake is running using the CPU at 100%.


#2

With no discrete GPU fitted and when using quick sync to encode, you won’t even notice quick sync is running. It uses around 25% of one CPU core for I/O, so the PC just runs as if there are no background tasks, and is perfectly usable.

Using a discrete GPU, you can still use quick sync via Lucid Virtu MVP. You get a fully licenced Virtu MVP with Z77 boards. If this is not supplied with the board, then don’t buy that board.

Regarding a discrete GPU, you’ll need a fairly new graphics card to outperform HD4000 in OpenGL games, as its about as fast as a Radion HD4870 when the HD4000 has a mild overclock.

Below is a Cinebench OpenGL benchmark. The bottom score is HD4000 at stock speeds. The higher score is HD4000 @1600MHz, which is a pretty mild overclock for HD4000.



#3

Regarding Quick Sync
I ripped a DVD to HDD with DVDFab (no compression), and then encoded the VOB files to MPEG4.

Media Espresso allows 4 streams to be processed simultaneously.
The VOB files were around 7GB in total, and here are the results.

Pic 1 Output DVD (720x576 pixels) - Total time for encode 2 minutes 38 seconds.
Pic 2 Output 720p - Total time for encode 4 minutes 22 seconds.
Pic 3 Output 1020p - Total time for encode 8 minutes and 9 seconds.





#4

Thanks a lot [B]Dee[/B] :bow:

I definitely want that monster CPU :eek:

The E8400 requires about 2 hours for a single movie :doh:


#5

Everything I’ve read about Quick Sync says it produces lesser quality output compared to software using X264. It is many times faster of course.

And the output may be perfectly acceptable for you, but I’ve also read that it is quite inconsistent, depending on individual movies used as the source.


#6

It isn’t quite as good as “software only” but very much better quality than Nvidia Cuda or hardware ATI.

You’d also need a very large screen TV to notice the difference between quick sync and software only.

The Quick Sync 2 codecs (Ivy Bridge) also give better quality than the original Quick Sync in Sandy Bridge.

It also depends on the compression level used. I’ve found 4MB/s is fine for DVD, but I use 9MB/s for HD, and I can’t detect any problems on a 37 inch TV.

I guess it depends on how critical you are. No doubt some folks will say Quick Sync is not as good, and I guess if I looked really closely I could detect a difference.

Having said that, the really critical will swear blind that a £50 HDMI lead gives better quality than a £5 HDMI lead, while most of us can’t tell the difference.


#7

Well, at least with video compression results, you can look at individual frames and see the compression artifacts that are introduced with different processes. Its not hard to pick out the blockiness in the dark backgrounds or the lack of edge sharpness, or even completely new errors that are introduced where they didn’t exist before.

So, it depends on your priorities…speed or quality. Quick Sync hasn’t progressed on the quality side enough to match X264. This is not to say it might not at some point, but Intel may decide its good enough for most uses now. And “good enough” isn’t going to satisfy a lot of video enthusiasts.


#8

Video enthusiasts are not a majority though, and just like people who overclock a PC, are probably a very small minority (less than 1% for overclockers) and I have no idea what the percentage would be for video enthusiasts.

Most folks will never overclock a PC, just like most folks only what to sit down and watch a movie in a form that they would consider good quality, IMO, Quick Sync does the job.

However, each to their own, and if someone does buy an Ivy Bridge system. Would it do any harm for them to try out quick sync and see what they make of it?
Even if they don’t like the result, they can easily use “software only” and it certainly won’t take as long to encode as it does on an E8400.


#9

[QUOTE=Dee;2637586]However, each to their own, and if someone does buy an Ivy Bridge system. Would it do any harm for them to try out quick sync and see what they make of it?
Even if they don’t like the result, they can easily use “software only” and it certainly won’t take as long to encode as it does on an E8400.[/QUOTE]

Oh I agree. And if I were in the market for a new computer using an Ivy Bridge cpu, one of the first things I’d do would be to test the Quick Sync process and do some direct comparisons. Even if I stuck with X264, the speed of the encoding would be a very big jump over my AMD hexcore system.


#10

To me, quality is paramount. If I had a slow CPU it would simply batch encode over night.

And the lay computer users out there in the internets, they need to be told what is good because they will always be happy with mediocrity because its free. :slight_smile:


#11

I would expect that a huge target for quicksync would be re-encoding dvd/bluray for portable tablets/phones. Artifacts on a 10" screen, would be insignificant.