ATI Stream: Finally, CUDA Has Competition

Why Only These Codecs?

TH: I know you can’t speak for Nvidia, but with both Stream and CUDA we only see acceleration for MPEG-4, layer 10. This ignores all of the media users currently have in formats such as DivX and Xvid. Why are we side-stepping MPEG-4, layer 2? And wasn’t there supposed to be acceleration support for Windows and WMV?

AMD: There are two points to your questions: acceleration of Microsoft applications and codecs supported in ATI Stream transcoding. From what I recall in material from last November, we included Microsoft applications like PowerPoint or Microsoft Expression that used GPU acceleration in their processing. It was not specific to transcoding. As for the codecs supported in ATI Stream transcoding framework, we had to make choices to be both effective in focusing our efforts while also covering the most use cases possible in a first iteration.

So why MPEG-2 and MPEG-4 AVC for GPGPU acceleration? We approached it this way: sources and targets.


  • DVDs: MPEG-2 SD
  • Blu-ray: MPEG-2 HD, MPEG-4 AVC, VC-1
  • Digital broadcast: MPEG-2  (SD & HD)
  • Camcorders:
  • HDV (which is a variant of MPEG-2 with resolution of 1440x1080)AVCHD for the new camcorders


  • Portable devices: H.264 (MPEG-4) & WMV
  • DVD authoring: MPEG-2 SD
  • Blu-ray authoring: MPEG-2 HD, MPEG-4 AVC, VC-1
  • File archiving with high quality/compression ratio:  MPEG-4 AVC, DivX, Xvid
  • YouTube: H.264

As you can see, with these two codecs, MPEG-4 and MPEG-2, we cover most user scenarios. Is there room of improvement? Of course, and we will work on it in future updates.

A note on DivX and Xvid: DivX is proprietary, and we would welcome having DivX support GPGPU acceleration, but that is a decision that is theirs to make. As for Xvid, it is open source, and the ATI Stream team welcomes developers on our Web site to communicate with them and get support if they want to develop a version that is ATI Stream-accelerated.

  • radiowars
    So..... TBH they both work pretty well, I hope that we don't start a whole competition over this.
  • falchard
    Did someone necro an old topic? I think ATI has been talking about ATI Stream for a while. I know atleast a year since FireStream.
  • cl_spdhax1
    arcsoft simhd plugin is currently only enabled for n- cuda graphic cards.
  • Andraxxus
    They're good but hopefully they will manage to improve them more. Competition is good for business.
  • DjEaZy
    ... why just now talk about? I use it sins Catalyst 8.12...
  • IzzyCraft
    Stream is old but not nearly as old and compatible as CUDA I'd get it a year or two more when more capable cards circulate the market and trickle down to the people before i would call it competition.

    Well it's good to see more then just 1 app that supports it.
  • ThisIsMe
    Just for the sake of it, and the fact that many pros would like to know the result, it would be nice to see comparisons like this using nVidia's Quadro cards vs. ATI's FirePro cards.
  • ohim
    why use 185.85 since those drivers are a total wreck

    13 pages with ppl having different problems with that driver
  • I think the second graph on the "Mixed Messages" page isn't the right graph.

    It's the same graph from the following "Heavier Lifting" page instead of a graph for the 298MB VOB file that should be shown?
  • Spanky Deluxe
    Stream and CUDA are likely to go the way of the dodo soon though. OpenCL's where its at. Unfortunately its a tad hard to get programming with it right now since you need to be a registered developer on nVidia's Early Access Program or you have to be a registered developer with Apple's developer program with access to pre-release copies of Snow Leopard.
    Virtually no one will bother using CUDA or Steam after OpenCL's out - why limit yourself to one hardware base after all? It'd be like writing Windows software that only ran on AMD processors and not Intel. Developers will not bother writing for both when they can just use one language that can run on both hardware platforms.