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GPU quality vs CPU only
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http://tech.slashdot.org/story/12/05/08/2217236/the-wretched-state-of-gpu-transcoding

Have you noticed using GPU acceleration produces different quality output than cpu only, as suggested by this article?
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vn800rider
Senior Contributor Private Message Location: Darwen, UK Joined: May 15, 2008 04:32 Messages: 1940 Offline
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I believe there has been much debate generally about the relative merits of GPU and CPU encoding. The issue of quality is, of course, bedevilled by how to define it.

Using mediainfo data as an indicator of the "technical quality" of a file, from memory, I recall that in previous versions of PD, CL's implementation of hardware acceleration produced very different file characteristics for the same chosen profile.

In the interests of modernity, (and to avoid any suspicion of a faulty memory) I have just run a test sequence with PD10 Ultra on my Asus i5 4gb win7 prof. laptop system which has the HD3000 integrated graphics with QuickSynch or a 1gb nvidia GT520M which I can select when starting PD.

The attached zip file has the following data in 12 files :-
The raw source file mediainfo data
Render times

Output file data for a 1080 60p custom profile (to activate SVRT)
HD3000 internal graphics as default :
No acceleration
QuickSynch
SVRT

nVIDIA GT520M graphics as default :
No acceleration
Acceleration
SVRT

Output data for the standard default Best Quality .mp4 profile
HD3000 internal graphics as default:
No acceleration
QuickSynch


nVIDIA GT520M graphics as default:
No acceleration
Acceleration

Does it mean any difference in quality - I don't know. I do know that any SVRT file produced like this does not play on WMP or my TV media player but does on VLC and MPCHC 64bit.

Cheers
Adrian
 Filename
MediaInfo.zip
[Disk]
 Description
 Filesize
10 Kbytes
 Downloaded:
341 time(s)
Life is really simple, but we insist on making it complicated. (see below)
Confucius
AMD Phenom IIX6 1055T, win10, 5 internal drives, 7 usb drives, struggling power supply.
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All vodi
Senior Contributor Private Message Location: Canada Joined: Aug 21, 2009 11:24 Messages: 1431 Offline
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All you need to do is search this forum and you will find that the majority of experienced editors use no GPU as it does tend to lead to lesser video quality. It is not PD10 that creates the issues it's the hardware encoding done by the graphics cards.

This message was edited 1 time. Last update was at May 09. 2012 14:10

Win 10, i7
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I can understand things like avivo and intel quicksync having a impact on video quality as they have their own rendering math. However using CUDA/STREAM should not have as much of an impact as you are offloading your own math and not using some other companies.

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All vodi
Senior Contributor Private Message Location: Canada Joined: Aug 21, 2009 11:24 Messages: 1431 Offline
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The way I read the article they came to the same conclusion: don't bother with GPU. Win 10, i7
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1Nina
Senior Contributor Private Message Location: Norway, 50km southwest of Oslo Joined: Oct 08, 2008 04:12 Messages: 1070 Offline
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Hi,

I am trying hard to understand what this is about.
On several occasions I have posted that “I am not the tech person here”,
and that’s oh, so true.
But, over the past 6-8 years, I’ve learned that knowing a little about
what stuff inside a computer is all about is an advantage.
Especially, if you’re about to spend ( a lot of)money on a new computer
and your purpose for buying is video editing, it will be good to have
done some homework.
Internet is filled with information as we know, but it’s not difficult to
find contradicting information- or opinions one might say.
On top of that, every company’s goal is to sell – whatever they are manufacturing
and/or selling. Marketing will be accordingly.

I read the article posted by Bastian this morning, and I have read it again
a couple of times during the evening. I have also been googling and reading
several pages on CPU / GPU. If you’re not in to numbers and specifications,
and you’re not in some way educated in tech-stuff, the reading will not
be a breeze. But an essential point will be: what, exactly, am I reading about?
I found a page describing CPU / GPU in a more “layman” way.
If what is said and described here is mostly correct, then maybe it can be easier
to understand – what this is about.
I hope the page is mostly correct, because I feel I learned some more today.

https://en.bitcoin.it/wiki/Why_a_GPU_mines_faster_than_a_CPU

Nina

Just something.
https://www.petitpoisvideo.com
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CubbyHouseFilms
Senior Contributor Private Message Location: Melbourne, Australia Joined: Jul 14, 2009 04:23 Messages: 2208 Offline
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Hi Nina

Thanks for the link - an excellent article

Bookmarked! Happing editing

Best Regards

Neil
CubbyHouseFilms

My Youtube Channel
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PD3.5, 5, 6 & 7. Computer: Dell Dimension 5150, Intel Pen. 2.80 GHz, 2GB RAM, NVIDIA GeForce 8600GT 256MB, Windows XP Pro!!
PD8 Ultra v3022. Computer: Dell Studio 1747, Intel, i7 Q740 1.73 GHz, 8GB RAM, ATI Mob. Radeon HD 560v 1GB, Windows 7 Ult. 64
PD10 Ultra v2023. Computer: HP Pavilion dv7, Intel, i7 2630 2.00 GHz, 8GB RAM, ATI Mob. Radeon HD 6770 2GB, Windows 7 Pre. 64
PD12 Ultra v2930. Computer: HP Pavilion dv7, Intel, i7 2630 2.00 GHz, 8GB RAM, ATI Mob. Radeon HD 6770 2GB, Windows 7 Pre. 64
PD13 Ultim v3516. Computer: HP Pavilion dv7, Intel, i7 2630 2.00 GHz, 8GB RAM, ATI Mob. Radeon HD 6770 2GB, Windows 7 Pre. 64
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stevek
Senior Contributor Private Message Location: Houston, Texas USA Joined: Jan 25, 2011 12:18 Messages: 4663 Offline
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Nina, You give yourself far too little credit. That article is a good discussion of the basics. It is becomming less relevant.

When CPU were slow dual core processors and the on board GPU were not very good. Buying and installing a good video card helped speed up the encoding/rendering. The GPU took the load off that double core processor. A video project that took several hours (or days) to finish was reduced to perhaps a 4 to 1 ratio. Four hours of rendering gave you a one hour video. I use that because one hour of video at best quality on a DVD is the optimum.

When multiple core CPU because more available - from dual core to Intel I7, there was a corresponding improvement of the onboard GPUs. So much so that many people chose not to put in an add-in card and there were no issues with time or quality.

ATI and Nvidia made more improvements so now encoding can be done much fater than real time. A one hour vidoe can be encoded in almost a few minutes.

Of course there are other factors that get into the equation. Bus speed, memory speed, memory amount and others to numerous to list I'm not going to discuss some anit-virus programs, e-mail and other programs being run at the same time which do have major effects). In some cases, there other factors almost force that people use software encoding. Those are the people who have issues with video card GPUs for one of the other issues mentioned above. Really, how many people shut down all othe rprograms, disconned=ct from the internet and shut down their anti-virus when editing video.

As the bottom line. Is a video with the same bit kbs rate, format, etc from a on-board video card better than one that is software encoded. Isn't that the same as what weighs more a kilo of lead or a kilo of feathers?

Sorry for pontificating but the question deserves it.

Also sorry for the spelling errors, I have yet to find the spell checker on this forum and no one will tell me if there is one.

This message was edited 2 times. Last update was at May 09. 2012 18:36

.
.
BoilerPlate: To posters who ask for help -- it is nice to thank the volunteers who try to answer your questions !
Anything I post unless stated with a reference is my personal opinion.
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Use google chrome as a web browser. Faster, more secure and has spell check by default. Then get a ad-block plugin.

As for my layman's explination:
a GPU is a super-efficient calculator. They were designed for handling triangle-math. Turns out the same kind of math can be applied to other things, freeing up the main computer to do other things. Physics, video redering, raw math. Then they found they could pack hundreds of cheap math-hungry processors onto one card. On NVIDIA these are CUDA Cores, on ATI they're STREAM processors.

If you can find a way to tackle your math problem in a way that hundreds of different parts of it can be worked on at the same time, then your project is perfect for CUDA/STREAM.

Unfortunately, not every math problem can be broken up into tiny pieces. (single threaded) Or nobody has done the work to figure out how to do it yet. That is why some codecs have hardware acceleration and some do not.

Recent video cards and intel processors have purpose-built capability to process video files.

In the case of intel quicksync the program you're using just sends the raw video to quicksync and tells it what you want to do to the video. Quicksync processes the video in the way intel programmed it to, and returns the result.

This means what ever program you're using to encode video, no mater who makes it, if they use quick sync the results are going to be identical. Because the video processing is being handled by intel's video transcoding utility.

When the program uses CUDA, they still have to write the program to convert the video. The difference is they have access to a very fast calculator that can run hundreds of operations at the same time. But it's THEIR program and math they're running.

It means a company like cyberlink can process a video 3 different ways:
1.) Regular old CPU. They write a program that uses 1 to 8 CPU cores at the same time to process video using their own math to do it.
2.) Using CUDA/STREAM on the GPU: They write the program to parse out the job into hundreds of tiny jobs that are all tackled at the same time. This requires processing video completely differently than the CPU approach. But it's fast.
3.) Offloading it completely like Intel quick sync or ATI's AVIVO. You have no control over what happens to the video. They just send it to the quick sync processor and say "convert this to mp4 at this quality setting" and it does it. You rely on intel to have made good design decisions in their math.

Writing the brains of your program 3 times (actually 5 times if you want to support CPU/CUDA/STREAM/AVIVO/QuickSync) is tedious and time consuming. That's why hardly any video editing company supports them all in the same product.

This message was edited 3 times. Last update was at May 09. 2012 19:03

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Senior Contributor Private Message Location: Canada Joined: Aug 21, 2009 11:24 Messages: 1431 Offline
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But the proof of the pudding as the old saying goes is in the eating. When using high resolution clips and still images (especially still images) a close scrutiny of the rendered frames shows a noticeably better rendering using the PC (= PowerDirector's software) versus that of the GPU. Having tested several different scenarios I no longer use the GPU as it does not buy enough time to make it worthwhile. Win 10, i7
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Carl312
Senior Contributor Private Message Location: Texas, USA Joined: Mar 16, 2010 20:11 Messages: 9088 Offline
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Quote:
Also sorry for the spelling errors, I have yet to find the spell checker on this forum and no one will tell me if there is one.

There is not a spell check on the forum but a spell checker in a browser toolbar works.

If you install a Google Toolbar, there is a spell checker that checks spelling in forms, which the forum is in the edit mode.
And text boxes are also.

http://toolbar.google.com/

I think there may be other browser toolbars that have spell checkers.

This message was edited 1 time. Last update was at May 09. 2012 23:23

Carl312: Windows 10 64-bit 8 GB RAM,AMD Phenom II X4 965 3.4 GHz,ATI Radeon HD 5770 1GB,240GB SSD,two 1TB HDs.

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CubbyHouseFilms
Senior Contributor Private Message Location: Melbourne, Australia Joined: Jul 14, 2009 04:23 Messages: 2208 Offline
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Quote: Having tested several different scenarios I no longer use the GPU as it does not buy enough time to make it worthwhile.


Hi HD

Do you turn off Enable Hardware Acceleration in PD preferences?



I personally do not use the SVRT prefering to use the Intel Quick Sync Video as I have had some artifacts etc when the SVRT has been enabled - file footage AVCHD 1920x1080 50i 24 mbps



Happy editing

This message was edited 1 time. Last update was at May 10. 2012 01:04

Happing editing

Best Regards

Neil
CubbyHouseFilms

My Youtube Channel
My Vimeo Channel
PD3.5, 5, 6 & 7. Computer: Dell Dimension 5150, Intel Pen. 2.80 GHz, 2GB RAM, NVIDIA GeForce 8600GT 256MB, Windows XP Pro!!
PD8 Ultra v3022. Computer: Dell Studio 1747, Intel, i7 Q740 1.73 GHz, 8GB RAM, ATI Mob. Radeon HD 560v 1GB, Windows 7 Ult. 64
PD10 Ultra v2023. Computer: HP Pavilion dv7, Intel, i7 2630 2.00 GHz, 8GB RAM, ATI Mob. Radeon HD 6770 2GB, Windows 7 Pre. 64
PD12 Ultra v2930. Computer: HP Pavilion dv7, Intel, i7 2630 2.00 GHz, 8GB RAM, ATI Mob. Radeon HD 6770 2GB, Windows 7 Pre. 64
PD13 Ultim v3516. Computer: HP Pavilion dv7, Intel, i7 2630 2.00 GHz, 8GB RAM, ATI Mob. Radeon HD 6770 2GB, Windows 7 Pre. 64
PD16 Live v2101 Computer: HP Pavilion dv7, Intel, i7 2630 2.00 GHz, 16GB RAM, ATI Mob.Radeon HD 6770 2GB, Windows 7 Pre. 64
Director Suite 6: PowerDirector 16 Live, PhotoDirector 9, ColorDirector 6, AudioDirector 8

Cameras: Sony(s) HXR-NX5P, HXR-NX70P, NEX-VG10E, a6300 4k, HDR TG5E, GoPro 4 Black, Canon 6D DSLR

Visit PDtoots. PowerDirector Tutorials, tips, free resources & more. Subscribe!
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- PDtoots happily supports fellow PowerDirector users!

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Senior Contributor Private Message Location: Canada Joined: Aug 21, 2009 11:24 Messages: 1431 Offline
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For those that have the inclination and time the following recent article gives a good update on GPU encoding's state of the art. The results of very intensive testing of 3 major bits of software trying to use the GPU is an eye opener and should help users of PD10 to decide and understand the pros and cons of GPU usage and why different apps produce different results.

http://www.extremetech.com/computing/128681-the-wretched-state-of-gpu-transcoding

This message was edited 1 time. Last update was at May 10. 2012 11:02

Win 10, i7
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1Nina
Senior Contributor Private Message Location: Norway, 50km southwest of Oslo Joined: Oct 08, 2008 04:12 Messages: 1070 Offline
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HD,

this is the article I read several times yesterday,
believing it was the >link Bastian posted.
Just something.
https://www.petitpoisvideo.com
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ynotfish
Senior Contributor Private Message Location: N.S.W. Australia Joined: May 08, 2009 02:06 Messages: 9830 Offline
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Yes Nina - it's the same article, cross-linked.

A good read, though! It'll take me a few times to take it in, too!

Cheers - Tony
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