6 Replies Latest reply on Nov 23, 2010 3:07 AM by tim_campbell

    Improve encoding speed for WMV output?




      Firstly, apologies if I am posting this in the incorrect area of the forums. I'm not entirely sure it's a hardware issue, I think it might be codec related.


      I am trying to find a way to reduce encoding times for a (on average) 4 minute clip using Premiere/AME CS5


      My input format is either XDCAM HD or IMX50, my output formate is always wmv, 720x 576 (PAL) interlaced, currently single pass encoding (because of the time taken) using the Windows Media Encoder (wmvencod.dll).

      There are no effects, nor transistions in my sequence. 2 tracks of video - 1 actual video, the second a logo overlay. 1 stereo pair for the audio.


      Hardware is a single Intel Xeon, quad core 2.5Ghz processor, currently with 10Gb memory. I have tried doubling up on the processors and also increasing the memory up to 16Gb but the improvements are marginal. Switching hyperthreading off also provides a marginal improvement in encoding time.


      I am running this on a server class 1u box. Currently it only has the standard vga server graphics card in it. I have mixed feelings about installing a graphics card as I have read conflicting information about whether it will provide an improvement in my encoding time.

      I don't think MPE is relevant, given that I'm not doing any effects processing.Will the CUDA architecture provide a significant improvement?

      I can only find 2 graphics cards that I think will fit in the box and these are the Quadro 4000 and Quadro FX 3800 that retail at around £650 - £800 + so it's a significant punt if they aren't going to provide an improvement.


      In essence, I have a template (well a couple of) project that I add the source file to each time that gets dropped into AME for encoding. For HD source encoding takes about 4 times real time. For SD it's about real time.


      If I chose a different output format, with the same input format eg h264 or DV (avi) then the encoding time is reduced to roughly 1/3rd of what I am experiencing at the moment. That gives me the impression that the wmv encoder is the bottle neck

      Are there alternatives to using the standard Microsoft WMV encoder? If so, how do I go about getting AME to use them, given that prior to installing Media Player I didn't even have wmv as an export option.


      Any thoughts on this would be appreciated.

        • 1. Re: Improve encoding speed for WMV output?
          davidbeisner2010 Level 3

          It may not reduce your encoding time at all, having to make two separate files, but Windows Media Encoder is a free Microsoft product that will convert pretty much any video file to wmv. You might get better results by exporting them to whatever is the "best settings to match the timeline" (getting fast exports) and then using WME to convert them to the settings you need. Just do a google search for Windows Media Encoder.


          Also, I don't believe upgrading your card would help you with your encoding in any way, especially if you're not using any gpu effects or transitions.

          • 2. Re: Improve encoding speed for WMV output?
            tim_campbell Level 1

            ok forgive me if I sound a bit dense here but is AME not using the Windows Media Encoder already to produce the output files? If so, then surely adding another step is only going to slow the process down rather than speeding it up.

            If it's not using the wmvencod.dll then what is AME using (or how do I figure out what it is using) since without those dlls present on the machine I don't even get wmv as an output option.


            Thanks for confirming my suspicions on the graphics card. So the CUDA processing would not provide any real benefit for pure conform?


            I should add that I am not averse to hardware changes that will improve the encoding speed, so a graphics card upgrade is not out of the question IF it will provide the improvements that I am after but so far the hardware changes I have experimented with have produced negligible gains.

            • 3. Re: Improve encoding speed for WMV output?
              davidbeisner2010 Level 3

              I couldn't tell you whether or not it uses the same dlls as the Microsoft program... that's getting deeper under the hood than I usually go! :-) If it is, then you're correct in that going to an intermediate and using WME isn't going to speed up your process.


              For more info on hardware, go to www.ppbm5.com and look at the test results page... see what folks were using who got the higher results. IIRC, your specific processor (even in its dual form) is a rather poor performer with this kind of stuff, and the Core i7 line is much better.


              Out of my own curiosity, I'm running a test on my system to see if I can reproduce the similarly long encode times with WMV versus h.264. I've got a 4:23 AVCHD clip which I'm rendering first using h.264 MainConcept to PAL DV Widescreen HQ (the only reason I'm using PAL here isbecause that's what you're using, and I wondered if it would go differently than NTSC... I've never used PAL before). The full encoding time for that in h.264 was about 1:45, so a little better than double real time. The same clip, rendered with WMV using PAL Widescreen source to HQ Download is taking about 3:15, so pretty much double the h.264 clip's time, but still better than realtime, and nowhere near the results you're getting.


              I don't remember what you said your HD setup was like, but make sure you've got multiple hard drives, preferably a RAID for your data disk. I learned that having a good disk configuration can really make a lot of difference, all other things being equal!

              • 4. Re: Improve encoding speed for WMV output?
                shooternz Level 6

                @ the OP


                I dont think that you said how long your encode times to wmv actually were?

                • 5. Re: Improve encoding speed for WMV output?
                  davidbeisner2010 Level 3

                  About 16 minutes, I believe... he stated that his clips were about 4 minutes, and it was taking about 4x real-time...

                  • 6. Re: Improve encoding speed for WMV output?
                    tim_campbell Level 1

                    That is correct, I am seeing roughly 4 times real time. In fact, 4 times slower than real time is the fastest encoding time I get when encoding to wmv.


                    The reason I believe that AME is using the wmencod.dll (and associated dlls) is that prior to these being present on the system wmv was not available as an output format in AME. The dlls were installed on the system by installing Media Player (as in Windows Media Player).


                    As far as hdd setup is concerned the box has two 15000rpm 72Gb drives using Raid 1. I appreciate that using fast disks with Raid 0 might improve encoding times (regardless of codec), although at present in my work flow the project files, hires media and output files are all using network storage.


                    Yesterday I tried a side by side comparison of QT wrapped H264 and wmv, using as close as possible to the same bitrate and other settings on a 1 minute HD file. The h264 took just over 3 minutes to encode, the wmv just over 4 minutes. In this test I used local storage to write the output files.


                    Clearly the h264 was faster and if the results extrapolate out to a 4 minute file I would be saving about 4minutes per encode.


                    Message was edited by: tim_campbell