VideoHelp Forum
+ Reply to Thread
Results 1 to 3 of 3
Thread
  1. Banned
    Join Date
    Nov 2005
    Location
    United States
    Search Comp PM
    just ran across this press release, evidently CUDA is making quite a splash in the commercial broadcast and film sectors:

    http://www.bjorn3d.com/viewnews.php?id=3693

    now any regular visitor to this forum must know that in general cuda accelerated encoding is considered inferior to software based encoders, particularly x624, but lately i have been wondering if the only reasons for that are

    1) all current desktop cuda accelerated h264 encoding apps use nvidia's reference cuda h264 encoder. this is true of cyberlink's offerings, media coder and badaboom, perhaps if these developers spent some time pouring over the x264 code they may get some ideas that would allow them to improve the quality of the cuda encoder

    and

    2) maybe the quality issues have more to do with the fact that desktop users tend to use gaming video cards and not high end workstation cards. now i know that geforces and quadros use the same basic gpu's but they are each "tuned" for different target audiences (much like how nehelam based xeons have more aggressive prefetchers and schedulers compared to their desktop cousins) and their respective drivers are also different, so i'm tending to favor the notion that many of the quality issues associated with gpu accelerated encoders are most likely the result of using a gaming card to do the work of a work station class card.
    Quote Quote  
  2. The x264 devs looked at this, and it won't work. There are pages of technical explanations at doom9 forum if you are interested (as this question gets asked alot), but to summarize, x264 would have to be completely re-written (not going to happen anytime soon)

    The architecture is the same for quadros as their desktop counterparts (with the exception of memory) , the only difference is in the drivers. It would make no difference with the x264 case
    Quote Quote  
  3. CUDA is a whole different beast from CPU processing, and all the encoding procedures have to be reimplemented within its constraints (e.g. completely different instruction set; lots of threads, but not individually powerful). CUDA encoders are still young in their evolution, so they'll have to go through the same evolutionary process that CPU encoders did.

    Any encoder's developers can study x264 to copy the ideas that have gone into it. It's just not happening very fast, from what I gather. And many of the ideas originally come from research papers published years ago, so it's not like x264 has any sort of monopoly on them.
    Quote Quote  



Similar Threads

Visit our sponsor! Try DVDFab and backup Blu-rays!