More Details on Elemental's GPU Accelerated H.264 Encoder
by Anand Lal Shimpi on June 23, 2008 10:52 PM EST- Posted in
- GPUs
Tucked away in our NVIDIA GT200 review was a bit of gold. Elemental Technologies has been developing, in CUDA, a GPU-accelerated H.264 video transcoder.
If you've ever tried ripping a Blu-ray movie you'll know that just a raw rip of just one audio and one video stream can easily be over 20 - 30GB. I've been doing a lot of this lately for my HTPC and even without 8-channel audio tracks, my ripped movies are still huge (Casino Royal was around 27GB for the 1080p video track and 5.1-channel english audio track). On a massive screen, you'll want to preserve every last bit of information, but on most displays you could actually stand to compress the video quite a bit.
Using the H.264 codec (or the open-source x264 version), it's very easy to preserve video quality but reduce file size down to the 8 - 15GB range - the problem is that it requires a great deal of processing power to do so. Transcoding from a H.264 encoded Blu-ray to a lower bitrate H.264/x264 can often take several hours, if not over a day for a very high quality re-encode on a fast dual or quad-core system.
Right now transcoding Blu-ray movies isn't exactly at the top of everyone's list, but using H.264/x264 you can significantly reduce file sizes on any video. x264 is the new DivX and its usefulness extends far beyond just ripping HD movies. Needless to say, its use isn't going to increase unless encoding using the codec gets faster.
Elemental Technologies has been working on a technology they called RapiHD, which is a GPU-accelerated H.264 video encoder and the consumer implementation of RapiHD is a software application called BadaBOOM (yes, that's what it's actually called, there's even a video).
RapiHD and thus BadaBOOM are both CUDA applications, meaning they are written in C and compiled to run on NVIDIA's GPUs. They won't work without a CUDA-enabled GPU (GeForce 8xxx, 9xxx or GTX 280/260) and they won't work on AMD/ATI hardware.
Elemental allowed NVIDIA to use a very early beta of BadaBOOM in its GT200 launch, which meant we got access to the beta. We could only transcode up to 2 minutes of video and we weren't given access to any options, we could only choose a vague output format and run the encode.
BadaBOOM uses its own H.264 codec that Elemental developed, we were forced to compare it to the open-source x264 in our tests since Elemental's software won't run without GPU acceleration. We used AutoMKV and played with its presets to vary quality. Even with the awkward comparison, the advantage of GPU-accelerated H.264 encoding was obvious:
Those numbers are compared to an Intel Core 2 Extreme QX9770, the fastest quad-core CPU available today. In the worst case scenario, the GTX 280 is around 40% faster than encoding on Intel's fastest CPU alone. In the best case scenario however, the GTX 280 can complete the encoding task in 1/10th the time. We're not sure where a true apples-to-apples comparison would end up, but somewhere between those two extremes is probably a good guesstimate.
Given the level of performance we saw with the GeForce GTX 280, we scheduled a meeting with Elemental's CEO, Sam Blackman to learn more about BadaBOOM as his application has the ability to truly revolutionize video encoding performance for the masses.
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7oby - Wednesday, June 25, 2008 - link
> Contrary to what someone else said x264 is being ported to GPUs and the project is active.>
Just Google this: Dark Shikari GPU
> It looks like Avail Media has hired a contractor who gets paid full time to work on the project.
I said that and it looks like my information is more uptodate (06/21/2008):
"Dark Shikari has already said that Avail Media is now going for FPGA's instead of CUDA ..."
http://forum.doom9.org/showpost.php?p=1151050&...">http://forum.doom9.org/showpost.php?p=1151050&...
Dark Shikari is working for Avail Media
PatMeenan - Tuesday, June 24, 2008 - link
Anand, I'm sure I didn't just see you publicly admit to violating the DMCA by ripping BD movies for your home theater, right?legoman666 - Tuesday, June 24, 2008 - link
He didn't rip them. He tripped over the power cable for the comp and when he got up, the movie had ripped itself somehow.icrf - Tuesday, June 24, 2008 - link
hehe, I was going to go with the slightly more feasible "I encoded them on a box overseas"JonnyDough - Wednesday, June 25, 2008 - link
You've been reading too many news articles about the U.S. Military "not torturing" "terrorists".michal1980 - Tuesday, June 24, 2008 - link
nearly all blu-rays are encoded using a 'next gen' codec. Ethier mpg4, or an AVC flavor.given that they are both efficent codecs. Why on earth would you want to compress that file even more? Loss of quality will happen.
to me, its like compressing mp3 to another mp3. At least when ripping DVD's to compress then to x264, you are taking mpg2, and putting in a new format that is vastly more efficent.
And while I see a need to rip the blu-ray to a harddrive(media center). To loss the new audio formats in the process, is destroying half the point of new formats.
legoman666 - Tuesday, June 24, 2008 - link
You clearly have never seen a HD rip @ 12gb. The difference between the 12gb reencode and the 30gb original is negligible.Re-encoding to 720p is also useful for people who don't have a 1080p display to take full advantage of the Blu-Ray.
icrf - Tuesday, June 24, 2008 - link
It's like buying CBR 320k mp3's from an online retailer, and transcoding them to VBR to save a little space on your mobile audio player. Makes perfect sense, especially if you'll always listen on the mobile device which isn't high fidelity and you can't hear the difference between the two. If I have a 720p HDTV at home and hardware that can't decode a 1080p stream, why would I spend the extra storage space on the original?michal1980 - Tuesday, June 24, 2008 - link
expect the video encoding is already VBR.If you are going for true quality, then why throw out data? I can almost understand the transcode from 1080p to 720p.
Still are you going to be stuck with a 720p display forever?
another poster said the difference is neglabile. Depending on the size of your screen, and moive then yes.
But i'd argue, that esspically if you are using it in a prue teather setting like Anand is doing, Then why? you spent thosands on the display/projector/screen, etc, a lot of money on the audio gear.
And then you are going to worry about sainvg 8gb on your hard drive?
how cheap is harddrive space these days? I saw 750gb for ~90 dollars
or about 12 cents a gb, Is it worth the the dollar, or buck fifty, a movie + processing time? I would venture to geuss that the electric bill to re-encode the movies, would make that difference in cost savings even smaller.
Unless you are really space limited, or doing it for compatiablity reasons. I'd rather have the data as original as possible. The enocders spent lots of times in most cases optimizing the encode, so it always looks good. No Automagic encoder is going to do that.
chrnochime - Tuesday, June 24, 2008 - link
I don't see why it's such an exciting news when you don't even know what kind of quality setting is being used by the transcoder.