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I'm a GPGPU snob when it comes to video transcoding

Posted on 8th Jul 2009 at 10:08 by Richard Swinburne with 13 comments

Richard Swinburne
If it ain't hundreds of frames per second, I don't want to know.

If I'm forced to use a CPU, it feeeeeeels painfully slow.

Everyday I get the train into London, and with the luxury of a 16GB iPod touch I usually watch an episode of something on the way in. The downside is that this usually requires transcoding video from a DVD or other source so that it works on the iPod.

Since my PC houses a still very capable GeForce 8800 Ultra, I decided it'd be worth having another look at Badaboom, the CUDA compatible GPGPU video transcoder.

It's come a long way since we first saw it and for the most part it works great - a 30 minute episode of animation or TV takes 3-5 minutes to do in the morning. By the time I'm out the shower it's ready to zip to the iPod and I'm out the door.

After some playing around I've worked out that a bitrate of about 900kbps is a sweet spot for quality and size, and while its simplistic interface opts for flashy over simple usability too much for my liking, it works. Most of the time.

It still lacks a lot of advanced features - due to the way some videos are already encoded, I've found some anime with hardcoded subtitles falls out of sync with the audio and I either put up with it or use another application to offset the audio. Another lacking factor is that, despite the fact it'll take a DVD's TS_VIDEO folder and churn out a whole movie from it - there's no subtitle support for foreign flicks.

And finally, the real laughable kicker is that I've found that - now it's summer - it overheats the graphics card so I get display driver resets causing Badaboom to continually crash.

For some reason, perhaps because it's CUDA and not a game, the drivers don't spin up the fan so the card simply cooks in silence. Admittedly I've also taken to trying some ~90 minute movies that take longer to encode, so I've found within my case environment it takes 6-7 minutes to crash - obviously I wasn't really seeing this beforehand with a 30 minute episode that finished in just four.

So out comes EVGA's Precision Tweaker, and forcing the fan to 100 percent fixed that while it encodes!

Crashes aside, I concede GPGPU makes my life more convenient. Part of me wants to throw more stuff at my graphics card simply because it's sitting there for long stretches of time doing nothing. It's not exactly value for money. I can generate a Windows Aero display on a £60 GeForce 8200 motherboard, and that's all my Ultra is doing all day long between (sadly, rare) bouts of gaming, so adding purchase value by using it as much as possible is something I'm all for.

It's what makes Ion (and products such as the Acer Aspire Revo) mostly useless - while on the workstation level companies are falling over themselves to develop apps for GPGPU, on the consumer end of things it's virtually all CPU still - which means on Atom, you really feel the limitations of the chip.

I just wish there was more open source transcoder development that took up OpenCL extensions, because having also briefly tried other CUDA consumer apps for sh**s and giggles, there's not much worth spending money on: TMPEG Xpress is hardly wonderful, and Cyberlink's MediaShow Express is overly simple and uses ludicrous amounts of unnecessary flashiness to try and mask this.

The bottom line is, if you're one of many who watches video while travelling, and chances are you have a compatible graphics card then give it a whirl, because it does make converting video a whole load more convenient. Just don't take more than four minutes to encode it!

13 Comments

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GFC 8th July 2009, 12:34 Quote
The best part of the blog post was "I've found some anime with hardcoded subtitles falls out of sync with the audio", you just rose up in my eyes.
Paradigm Shifter 8th July 2009, 13:24 Quote
Unfortunately, as much as the GPGPU video encoding/transcoding programs have improved, until they get all the quirks out like audio/video desyncing... I'd rather use the CPU and have it go perfectly.
jeffbr13 8th July 2009, 13:48 Quote
Really? With a Q6600 (at stock speed, and recommended by Bit-Tech, may I add!) and Handbrake, it really doesn't take very long to transcode videos, especially into iPod format. Plus, there are no cooling problems, and I can customise and save my own profiles for different devices. In fact, the only problem seems to be an enforced limit on how many fps it can do (about 330, with only 80% CPU usage, when transcoding into lower bitrates)! I can understand why people get annoyed by limiters on fast cars now!
deeem119 8th July 2009, 14:22 Quote
I had thought of getting a newer video card for encoding, but this makes me question it. My i7 920 encodes videos for my iPhone (on any encoder I fancy using) at 250+fps, meaning around 3-4 minutes for a 30 minute episode., and will continue encoding long lists of episodes for hours on end without overheating, if I line up an entire series. I can overclock it and get around 400+fps, and even then (using a stock intel cooler) it doesn't overheat and crash for around 30 minutes. I think I'll just spend my money on a better cooler and go for the overclock...
yakyb 8th July 2009, 16:51 Quote
yeah whilst CUDA is great and all the shear number of availible good quality Freeware Encoders availible for the CPU is just too much to pass on.

until some Cuda developers start releasing Customisable Staxrip / handbrake style encoding facilities ill be sticking to the CPU.

I think this is something Bit-Tech should really keep an eye on! then offer up a review / Bit once it finally happens.
bubsterboo 8th July 2009, 17:04 Quote
I agree with you for the most part. I love CUDA and the idea of using all that spare power in your GPU to do something useful that isn't playing video games. But I don't think the software that supports CUDA is up to par with my demands quite yet. I love the Quality and size I can produce from the x264 encoder for my iphone. Though it does take incredibly long.

x264 Supporting OpenCL would be the all round king IMO. And I hope it's not too long until we see that happen.

Though my encoding chain isn't totally dependent on the CPU. I use my GPU to decode the video source. Doesn't help much, but if it's 1080p HD it helps a lot.
wuyanxu 8th July 2009, 17:37 Quote
encoding via CUDA is useless, no control over video bit-rate and iphone video ended up bigger than my youtube HQ source!

CUDA is a good starting point, but wait for OpenCL for a proper GPGPU standard. the exclusion of ATI users won't help nVidia any bit.
Bindibadgi 8th July 2009, 18:13 Quote
Quote:
Originally Posted by wuyanxu
encoding via CUDA is useless, no control over video bit-rate and iphone video ended up bigger than my youtube HQ source!

CUDA is a good starting point, but wait for OpenCL for a proper GPGPU standard. the exclusion of ATI users won't help nVidia any bit.

Badaboom gives you complete control over bitrate in the advanced options but I do agree with you - the file ends up little smaller than the original.

The point of using the GPU is that I can get on with other things using my CPU. If I load up my CPU the system chugs - it's just a better balance of resources.
Bindibadgi 8th July 2009, 18:14 Quote
Quote:
Originally Posted by deeem119
I had thought of getting a newer video card for encoding, but this makes me question it. My i7 920 encodes videos for my iPhone (on any encoder I fancy using) at 250+fps, meaning around 3-4 minutes for a 30 minute episode., and will continue encoding long lists of episodes for hours on end without overheating, if I line up an entire series. I can overclock it and get around 400+fps, and even then (using a stock intel cooler) it doesn't overheat and crash for around 30 minutes. I think I'll just spend my money on a better cooler and go for the overclock...

Respect to that - but if you've already bought a graphics card that's sitting there doing nothing, it doesn't mean you need to fork out for a 920, X58 mobo, lots of DDR3.

However, on the other side, a 920 OC makes general productivity a lot faster too..
wuyanxu 8th July 2009, 20:49 Quote
Quote:
Originally Posted by Bindibadgi
Badaboom gives you complete control over bitrate in the advanced options but I do agree with you - the file ends up little smaller than the original.

The point of using the GPU is that I can get on with other things using my CPU. If I load up my CPU the system chugs - it's just a better balance of resources.
i believe the bit-rate only goes down to 500 in all programs.

yes, it's very good to be able to offload to GPU, in fact it will be fantastic on liking of Atom. but for a proper desktop, it's not mature enough to take over CPU just yet

also, GPU isn't very good at scheduling, because its got such a small amount of per-thread cache. i can't Fold while watch HD videos smoothly :(
Aracos 8th July 2009, 21:54 Quote
Quote:
Originally Posted by GFC
The best part of the blog post was "I've found some anime with hardcoded subtitles falls out of sync with the audio", you just rose up in my eyes.

+1

I get Audio/Sub sync problems a lot when I was transcoding Anime for my Nokia N73 (Using Coreplayer allows for Xvid <3) and I find most transcoding programs are useless for my needs, All I usually watch is Anime in japanese only so from the usual suspects I get it in MKV format with stylised or normal softsubs and most transcoders don't give a crap how many audio tracks or subtitles tracks it's got which annoy's the hell out of me so being the AMD fanboy I am ATI Stream can take a running jump. For me I just stick with AutoMKV for it's extreme uberness allowing you to do basically everything and has a helpful author that will tell you what you are doing wrong if a problem occurs.

PS You've risen highly in my books for your love of the japanese audio MUHAHAHAHA!

EDIT: Seeing you have an 8800 Ultra in your comp really surprises me, I expected everyone at bit-tech to have 5GHz OC'd i7's with LN2 cooling and 4 GTX 295's all in SLI XD Please don't quote me on that, I don't know if you can use 8 GPU cores at once or not T_T
Psytek 9th July 2009, 05:15 Quote
"hardcoded subtitles falls out of sync with the audio and I either put up with it or use another application to offset the audio. "

Which application do you use to do this?
BLC 9th July 2009, 14:17 Quote
I usually only have to worry about transcoding videos to put them on my PSP. Because it only supports one or two video codecs (only one really, if you want good quality) and quite a low resolution (480x272, IIRC), there aren't many options for transcoding software. The ones I do use do the job very well in terms of quality, but are really lacking in speed (but I do use a high audio & video bitrate and two-pass encoding).
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