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  1. Member
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    Alright, so I'm going to build myself a new computer, and I plan on putting a quad-core processor in it. This is the processor that I want, actually. I also plan on putting the 64-bit version of Vista on my new computer, if that makes any difference.

    I'm wondering if processing video, specifically compressing video using Divx, Xvid and x264, will use all four cores of a quad-core processor? Or does it depend on the program I use to compress video with? The primary programs I use are VirtualDub, avidemux, occasionally Windows Movie Maker and a few other random ones once in a great while. I also use DVD Shrink sometimes, even though that actually reencodes VOBs.

    I've looked around the web, but could find basically no information on this, so if anybody knows anything, I would greatly appreciate it. Thanks a bunch in advance.
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  2. x264 scales particularly well with the number of cores. Divx and Xvid not as well but still faster than 2 or 1 cores. The codecs themselves can spawn multiple threads so even if you are using a single threaded editor you will benefit from multiple cores.

    https://forum.videohelp.com/topic363342.html
    https://forum.videohelp.com/topic336716.html
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  3. Xvid and divx can use up to two cores, x264 can use more ..... use as many cores as an Irish Rock band, but not as many as a "Carry on" Film.. thats my motto
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  4. Mod Neophyte Super Moderator redwudz's Avatar
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    There is also a newer comparison thread by graysky: https://forum.videohelp.com/topic347859.html
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  5. Originally Posted by RabidDog
    Xvid and divx can use up to two cores
    Xvid and Divx definitely encode faster with 4 cores compared to 2. I don't think there's any improvement over 4 cores but I can't test that.
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  6. The above only applies to a straight encode, no filtering with limited settings.

    As soon as you use any filters (e.g. resizing, color filters, noise filters, deinterlacers etc...), they usually aren't coded to be multithreaded or optimized poorly - so they become the bottleneck.

    Some recently implemented x264 settings are not multithreaded, e.g. --b-adapt 2; and may be the bottleneck. Graysky's testing & benchmark was before the new b-frame decision

    If you can't "feed" the encoder fast enough, using all 4 cores or 16 cores is a moot point, when the filter/settings limit you to 1.
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  7. Originally Posted by poisondeathray
    The above only applies to a straight encode, no filtering with limited settings.

    As soon as you use any filters (e.g. resizing, color filters, noise filters, deinterlacers etc...), they usually aren't coded to be multithreaded or optimized poorly - so they become the bottleneck.
    Obviously, if other bottlenecks exist a multithreaded encoding codec won't improve overall performance as much. At least VirtualDub can split the encoder into thread separate from filtering now. So unless you are doing a lot of filtering (Neat Video for example) you still get a decent improvement with four cores vs two.

    You can also encode two or more videos at the same time to get improvements in throughput. Until I/O becomes the bottleneck.
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  8. Take a look at the E8400 3 GHz dual-core - it's about the same price, and will run faster than the quad when you have filters bottlenecking your video. I used an E8400 in a recent build and the client loves it.
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  9. Originally Posted by Constant Gardener
    Take a look at the E8400 3 GHz dual-core - it's about the same price, and will run faster than the quad when you have filters bottlenecking your video. I used an E8400 in a recent build and the client loves it.
    The E8400 will outperform the Q6600 in many (video encoding) tasks because of the higher clock speed and architectural improvements (and single threaded nature of many filters).
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  10. Member
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    Sorry for the late reply, guys.

    So, putting the model-specifics aside, the verdict is basically that quad-core is faster than dual for encoding, unless a filter is involved because they are only programmed to use one core. But if VirtualDub is used, it makes the filter use one core while the codec uses the other remaining cores?

    I'm upgrading from a single-core 2.8Ghz Celeron, so really, no matter what I get will be an improvement, but I want something that's decent compared to the other processors on the market. Also, this isn't a passively worded question. I've pretty much decided already (unless some radical new information comes my way) - only just gathering some information so I know what I'm getting myself into.

    By the way, thanks for the information, I really appreciate it!
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  11. Always Watching guns1inger's Avatar
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    If you are a Vdub user, have a read of this thread : https://forum.videohelp.com/topic361608.html
    Read my blog here.
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  12. Originally Posted by sincostan45
    So, putting the model-specifics aside, the verdict is basically that quad-core is faster than dual for encoding, unless a filter is involved because they are only programmed to use one core.
    Not exactly. It depends on how much time the filtering takes relative to how much time the compression takes. If a conversion is 5 percent filtering (say, a simple crop and resize) and 95 percent compression (Xvid at high motion search precision settings) you will get a significant improvement by having 4 cores instead of 2. If the job is 95 percent filtering (say, Neat Video) and 5 percent compression you will not see a significant improvement.
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  13. Member
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    Yes, I am a heavy VirtualDub user, so it would seem that I will be able to take advantage of that multithreading that was talked about in that thread you linked me to.

    I had not considered that the processing power varies from filter to filter. It actually all makes sense now. I don't use processor-intensive filters that often, but when I did, I did notice that I wasn't compressing as fast as usual.

    When I use VirtualDub, I typically use filters related to deinterlacing (discard one field) and resizing. The processor-intensive filters that I was using were related to cleaning up crappy analog captures. However, I don't capture from those kinds of sources very often, so what I do 99% of the time is discard a field and resize. And in fact, I want to start capturing progressive signals, so I wouldn't even need to deinterlace or resize anything, and therefore, use no filters.

    So, in this case, I suppose four cores is significant improvement over two, huh?
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  14. If you are building look at the chart for cpu's performance I posted
    https://forum.videohelp.com/topic363342.html
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  15. Originally Posted by sincostan45
    When I use VirtualDub, I typically use filters related to deinterlacing (discard one field) and resizing.
    I ran some benchmarks on my Q6600 for you. I started with a 720x576 25 fps ~22 minute PAL MPEG2 file. In VirtualDub 1.9.0 I added the Deinterlace filter with the Discard Field 1 setting. Then resized to 512x384 with Lanczos3. I used Xvid in Target Quantizer mode (Q=3), Motion Search Precision at 6, VHQ Mode at 4. I used the NUMPROC setting in BOOT.INI to set the number of cores Windows XP SP3 can use. I set Xvid to use the same number of threads. Here are the encoding times:

    1 core, 740 seconds
    2 cores, 459 seconds
    4 cores, 351 seconds
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