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CBR 2 pass

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  • CBR 2 pass

    With the addition of a new CBR 2 pass mode for WMV export, would someone mind running down the list of CBR, CBR 2 pass, VBR, VBR 2 pass and help me to understand the differences and suggested applications for each?

    Much appreciated.
    Joe Shaw
    Freelance Director/Editor

  • #2
    Personally I don't see what good 2-pass CBR does -- the bitrate is fixed and there is no point in distributing the data. Each frame has the same bitrate budget that can be used to encode it.

    With VBR, 2-pass/multi-pass can improve playback quality by allocating more of the bitrate for complex scenes containing lots of detail or fast motion, taking bandwidth from nearby scenes that are mostly static and less complex. The encoder makes one pass to analyze the content, and a second (or several) pass to do the encoding.


    • #3
      With the addition of a new CBR 2 pass mode for WMV export,
      It has to do with streaming media, I remember reading an article by Ben Waggoner where he recommended 2 pass CBR for WIN Media encoding except for live streaming, but its been more than a year, so I don't remember his reasoning.
      GA-EP45C-DSR3,Core2Q3ghz,8gig1066,260GTX,2x 20"AOC,22"Vizio1080pTV, Edius5/HDspark,PC3,Imaginate, CS5ProdStudio/IntensityPro,Win7_64
      HPdv7t 17"notebook,8gig,2 IntHD,9600GT512M,17"extmon, Edius4.61,CS4Prodstudio.Win7_64,MX02Mini
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      Numerous Ext eSATA drives & Raids shared between systems


      • #4
        If Ben says it, then I believe it!


        • #5
          2-pass CBR can still help to "smooth out" little "bumps" in quality. It's not as much smoothing as 2-pass VBR, but it can still help.