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PC spec for real time AVI compression.

Discussion in 'Camcorders, Action Cams & Video Editing Forum' started by Darren Blake, Sep 20, 2004.

  1. Darren Blake

    Darren Blake
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    Quick question:

    I want to do some high-quality video capture from an analogue source at full frame (7xx by 5xx @ 25fps). To keep the file size (1Gb per minute) down I need to do real time compression. Ideally I'd want to use either HUFFYUV or Ligos Indeo 5.2 with the quality set to about 90%.

    My current PC (1.7GHz Celeron S478, 256Mb RAM) can't handle the frame rate and bombs out at about 5fps.

    What hardware specification - specifically processor and RAM - will I need to get up to 25fps and beyond? I am poised to buy 1Gb and a 2.8GHz P4 with 1Mb on-chip cache, but it's over £200 and I'd be gutted if it didn't get me all the way there.

    TIA.
     
  2. Marc

    Marc
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    how about getting a 3.06ghz p4 with hyperthreading, which should manage the process without maxing your cpu processing time, which is possibly part of the reason it bombs out. Of course it partly depends whether the software you use takes advantages of a HT CPU or not.
     
  3. MarkE19

    MarkE19
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    I've got Ulead DVD Movie Factory 3 and on the box it lists 'direct to DVD capture' as needing a P4 1.8Ghz/Athlon 1.7Ghz processor and 512Mb RAM

    Different programs will require different specs to work properly. Check what you will be useing and go for the recommended specs and not the minimum specs stated.

    Mark.
     
  4. Darren Blake

    Darren Blake
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    The software I use is Puremotion Editstudio. My PC is already way above the minimum spec (500MHz if memory serves). I'm not sure wether the minimum spec will cover real time encoding using different codecs as there are so many different permutations to do the same job. For example, my machine can almost handle 25fps using HUFFYUV but only manages a fifth or that with Indeo.

    My mobo has a 533MHz FSB, so I'm not sure I could go all the way to over 3GHz. I'm not sure my wallet could, either!

    So what's the main issue? It can't be as simple as speed because your 1.7GHz P4 can do the business. Is it processor architecture (P4 versus Celeron)? On-chip cache? RAM?
     
  5. Marc

    Marc
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    there are so many variables for this sort of thing. For instance, if your hard disk isn't fast enough, or is fragmented, the access speed may not be able to keep up with the encoding, which will cause it to bomb out, or cause imperfections in the encoded video. You might also find that other process writing to the disk can interfere with the writing of the video stream, which is why it's recommended to have a seperate hard disk to write the file to.

    if your cpu is constantly maxed out, you are going to get some queuing of instructions during the process which again could cause it to bomb out, and if your memory fills up, your computer will begin to use virtual memory which will be very slow, and also possibly be accessing the same hard disk you are saving the video to.

    So much to consider.. try bringing up the Task Manager next time you're encoding and find out if your CPU is being maxed out, or your memory getting low, as you might be able to get an idea of what the problem is.
    You may even find it's just rubbish software.. if it came free with the capture card, it may well be!
     
  6. Darren Blake

    Darren Blake
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    Ok, I can shed a bit more light on the problem:

    It's not (as far as I can tell) a disk issue.
    The disk is a new-ish 60Gb 7200Gb job with a 2Mb cache and all the good DMA stuff turned on. It's also been freshly formatted as NTFS. It can handle the data rate to write uncompressed frames (1Gb per minute), so it should easliy be able to handle a compressed file.

    I have checked Task Manager while capturing and yes, the processor usage does max out (100%), so the simplest solution would seem to be to get a much faster processor. However I am confused by the reports (as above) of similar clock speed processors getting much better results than I do. I have had some indication that my main problem may be that my processor is a Celeron rather than a full-fat P4.

    Going by the figures, I'm looking for a 500% speed increase to get from 5fps to 25fps, which doesn't equate to going from 1.7GHz to 2.8 or even 3.2GHz on the processor. There must be other factors at play.

    One thing I do need to do is get more RAM. XP just doesn't run very well with only 256Mb. Is it likely that changing this alone will make much of a difference?
     
  7. Marc

    Marc
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    about the hdd:
    is the hard disk you're talking about your c:\ drive? If so, you have to remember that Windows is constantly accessing it for other things too, so you can get a conflict. As an example, try defragging your c:\ drive while still using your PC and you will notice it takes about 10x longer than if you close down all apps and leave it going.

    about the cpu:
    It's unlikely that the video editing program will need a 3ghz, or even a 2ghz processor, as in itself 1.5ghz is probably enough speed to keep up with the calculations, but the processor is possibly choking from the sheer amount of calculations sent to it in a single burst, which is why having a 3ghz hyperthreading cpu, which would double the bandwidth, effectively giving you 2x 1.5ghz cpu's, should allow for faster calculations.

    about the memory:
    256mb on XP is very low. Generally most if not all of that could be used up just by the OS and services if they're all doing something, and even if they're not, Windows is a bugger for releasing memory it's using. So the chances are that your PC is using virtual memory, which will cause an immense performance dip, and like i said before, if the paging file is on the same disk as the video file you're creating, it'll kill it. I have 1gb on my PC and when more or less idle, i have about 700mb free, which would mean you have a lot to play with before your paging file gets called into action.

    Double your ram to 512mb and see how much difference it makes. it's the cheapest solution, so the best place to start. I'm not sure about sockets etc, but its likely that you will need to get a new motherboard if you get a newer P4 CPU, and to go with it, new memory, so if you can survive on your Celeron, you'll save a lot of money!
     
  8. Darren Blake

    Darren Blake
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    The hard disk is a dedicated drive expecially for video editing. I have three HHDs and one DVD writer. C and D (my "system" and "data" drives are on the primary IDE controller. The video editing drive (E) and my DVD writer (F) are on the seconday controller. Like I said, they can take the full 1Gb / minute data rate for uncompressed capture, so I don't think drive speed is the issue.

    I agree with you about the processor. Editstudio runs fine on it. It is the sheer number-crunching that the real time compression requires that is maxing it out. Unfortunately, no-one seems to be able to tell me what speed I actually need to make it work. :(

    Memory: OK, I need lots more - that's a given. I'll probably do what you say and go up to 512Mb as it would seem that I need to do that anyway. I'd like to go to a full 1Gb but maybe investigating in stages is the wiser thing to do. If going to 512Mb doubles the framerate alone, then that would be something.

    Is there any way I can use Task Manager to check virtual memory usage during a capture?
     
  9. Marc

    Marc
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    you can look on the performance tab of device manager, at the section called "page file usage history" which should show you if the page file is being used. normally it'll be a flatline but it'll be spiking a lot if it's in use. Also I have a feeling that the "commit charge (k)" section shows you how much memory (physical + virtual) is being used at any given time.

    In terms of the CPU, i don't think there's any set speed that will guarantee success but the main thing to remember is that over time the technology has improved, so by getting for instance a 3ghz pentium, you're not necessarily getting just a 1.3ghz improvement, as you're also getting the added improvement of the technological advancements made, such as larger cache and hyperthreading technology. If you're planning on 2.8ghz, i would definitely recommend spending a litle extra to get the 3ghz hyperthreading cpu, as i believe you will get much more than tha 200mhz improvement it looks like you're getting.

    You might find it worthwhile asking a pc shop such as pc world if you can install your video software/hardware on one of their pc's matching the spec you think you want to see if it can handle what you need it for. If they want the sale they should agree, and then you can just leave saying you need to think it over.
     
  10. Darren Blake

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    OK, I'll check that out tonight. Cheers for that. :)

    BTW, I meant to say perviously that my motherboard is documented as being able to take up to 2.5GHz processors which were the fastest out at the time. Its a fairly new (two years old??) MSI job with a 533MHz FSB, so hopefully it will be good for all bu the fastest P4 processors.

    You must have a very helpful PC World! :D My local one hardly know anything about the hardware they sell and I certainly wouldn't let them anywhere near my PC! As for puting my software on one of their machines I reckon that would be equally doubtful, plus I would need an analogue capture card and access to a video source all in the shop...

    ...but what I DO have is a mate who just happens to have a 2.8GHz P4 and 1Gb of RAM in his PC. I wonder if he would let me borrow them for a couple of hours...? There's a thought!
     
  11. MarkE19

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    Now I think we may have found the problem.
    The problem with the architecture of the IDE bus is that it can only run at the speed of the slowest device connected to it. In your case that will be the DVD drive which is considerably slower than even old/slow HDD's. I would suggest putting the video drive 'E' as the slave on the primary controller along with your boot/system 'C' drive and putting your 'D' Data drive on the secondary controller.

    Mark.
     
  12. Darren Blake

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    Well, I stopped short at swapping my drives over, but I tried some captures to my D: drive (slave drive on the primary controller - where you suggest my video drive should be) and the performance was pretty much identical. :( Like I said before, my drive can handle the data rate for uncompressed frames at DVD res at 25fps, so writing compressed frames shouldn't be an issue.

    Good point, though, and maybe something to consider when it comes to DVD burning etc.

    I've checked out the performance under Task Manager and to be honest nothing seems to be goign crazy. The page file usage remains pretty flat even when I'm really pushing it using Indeo. The one thing that does show some clear trends is the % CPU usage, though. On all the failed capture attempts it clearly maxes out before the capture bombs.

    Its looking like a pure processor power issue, but it will be an expensive upgrade for nothing on the offchance it isnt.

    As an aside, I'm amazed that HUFFYUV (a codec which looks like it has been written by someone as a hobby) is not only free, but super-fast AND lossless. Compare this to Indeo 5.2 which is now proprietary, lossy and only capable of 1/5 of the framerate on my PC.

    What's that all about, then???
     
  13. BadAss

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    I had a major problem when I added a second drive. I formatted it to NTFS but when I captured files they would all be corrupt. But when I captured to to the C: drive which was still FAT32 things were fine. It was only when I formatted my C: drive to NTFS that both drives began to work together.

    I dont know if this is your problem but I'm sure if both or all drives are the same format everything should work.
     

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