cpu - What affects video encoding speeds?

08
2014-07
  • pighead10

    FRAPs doesn't compress its videos when you record, so the files are enormous. In a long recording you can get up to a few hundred gigabytes.

    Obviously, usually you would need to convert/compress them. What affects the speed of this? I don't think the RAM does, as when I converted 600 gb my RAM usage only went to 6 gig, but the processor was at 100%, which is surprising as I have a 6 core processor @ 3.46 ghz. Would clock speed or cores help the most?

    • Answers
  • Daniel Andersson

    Since encoding is usually a highly parallelizable task, many cores will give an almost linear gain (i.e. 6 cores is ~three times as fast as 2 cores).

    See e.g. http://macperformanceguide.com/Optimizing-Handbrake.html for some real life numbers. The article also mentions that at least Handbrake doesn't scale well beyond 9 cores, so many more than that won't increase speed (unless you run several parallel jobs, which probably is connected to other slowdowns, though).

    RAM is used to keep the images in memory which is needed, but the limiting factor will almost always be CPU power.

    So: if all you want is encoding performance, cores will give you the best boost per monetary unit (within reasonable bounds).


    • Related Question

    windows - How do I use my gpu to speed up video encoding
  • Nifle

    I have a ATI graphics card (Radeon HD 4870), I have read that I can use this to significantly speed up encoding dvd to avi.

    Does anyone know how?


    • Related Answers
  • BenA

    The ATI Catalyst drivers now come with the Avivo video converter. This should do what you're looking for, though I haven't tried it myself.

  • Drake

    You need to look at ATI Stream Technology if you want to being able to really gain significant speed increment in encoding/decoding videos. That is the ATI answer to CUDA from NVidia.

    Both technologies aim to allow software developers to program GPU (GPGPU) to increase the performances of their applications.

    Here it is the ATI web page that describe how ATI Stream could accelerate the digital home entertainment.

    I hope we will see many SW in feature that will use more our GPU also when we are not playing :D