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best MPEG2 decoder for Matrox+SDTV

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  • best MPEG2 decoder for Matrox+SDTV

    ok I've been playing around with some DirectShow MPEG2 decoders, and so far have the following findings:

    Elecard filter (v2.0.3611):
    - Doesn't weave interlaced encoded streams properly. This makes it rather worthless for outputting to SDTV.
    - Uses a lot of cpu time. Double precision iDTC mode kills my PC (P4 2.8 GHz).
    - Output of single precision iDTC looks nearly identical to WinDVD YV12 output or BitControl output.

    Sonic Cinemaster (v2.5.03.0806):
    - Doesn't weave interlaced encoded streams properly either, making it as useless as the elecard one.
    - Has very low CPU demands

    WinDVD (v5):
    - Weaves properly
    - upsampling of chroma to YUY2 is done by line-doubling (this looks awfull!). When you load ffdshow to upsample to YUY2, the video stream will often halt. The only solution is to insert the Intervideo Abstract DMO filter, but this filter only outputs YUY2, defeating the purpose of ffdshow.
    - YV12 output looks acceptable, comparable to the BitControl and Elecard filter.
    - CPU use on test sample in YUY2: 16 seconds cpu time (same result for YV12)

    DScaler5(v001 alpha)
    - Force Weave and Force Bob are the wrong way round in this release (but weaves properly when set to 'force bob')
    - you have to disable 'Preserve source cropping' in the DVDMAX properties to get proper output with this filter on the TV
    - some artifacts (chroma bleeding?) when compared to WinDVD YV12, Elecard and Bitcontrol output.
    - CPU use on test sample in YUY2: 23 seconds cpu time

    - Force weave works properly on interlaced contents.
    - Output looks nearly identical to WinDVD YV12 and Elecard filters.
    - CPU use on test sample in YUY2: 18 seconds cpu time.

    next up to be tested are NVDVD3, PowerDVD and WinDVD6 filters. First I'll do cpu useage tests and weave deinterlace tests. When I get my calibration DVD (which is in the mail), I'll start doing some image quality comparisons.

    YV12 output (to prevent Chroma upsampling by line-doubling in WinDVD) with DVDMAX causes green/pink colours when the deskstop is in 32bpp colour depth. I guess this is a driver bug in the G400?

    You can theoretically upsample YV12 to YUY2 with FFDshow, at added CPU utilisation costs:
    configure a recent FFdshow build to load with 'YV12' RAW VIDEO codec. Enable overlay mixer, and disable all output colourspaces except YUY2.
    However, WinDVD doesn't like any filters to be connected to it other than the Intervideo Abstract DMO filter, which can only output YUY2
    Last edited by dZeus; 17 August 2004, 12:32.

  • #2
    Hi DZeus!

    Maybe you're interested in giving the mediaplayer classic a try. It uses the libmpeg2 which is quite highly regarded.

    Both projects are opensource, you find the player at

    Cheers, Hannes


    • #3
      DScaler5 is based on libmpeg2 (and DirectShow)


      • #4
        Thanks for this test, it's interesting
        System : ASUS A8N SLI premium, Athlon 64X2 3800+, 2Gb, T7K500 320Gb SATAII, T7K250 250Gb SATAII, T7K250 250Gb ATA133, Nec ND-3520, Plextor PX130A, SB Audigy 2, Sapphire Radeon X800 GTO, 24" Dell 2407WFP.


        • #5
          I found out that my testing methodogy is flawed. Appearantly the screenshots I take have significant errors caused by a sloppy colourspace conversion routine in ffdshow (YV12 to RGB or YUY to RGB) which is used for the screen grab feature in ffdshow.

          So... I'll have to find another methodogy first (or wait till ffdshow gets a better colourspace conversion algoryhtm)