iDCT Algorithm

• iDCT algorithms possess the quality of MPEG-2 decoding.

• First of all, these three iDCTs are all IEEE-1180 compliance which confirms the quality of iDCT algorithms. It's really hard to tell the difference perceptually.

• Generally speaking, speed of 32-bit MMX/SSEMMX/SSE2MMX > 64-bit Floating Point > IEEE-1180 Reference iDCT. In view of this, 32-bit MMX/SSEMMX/SSE2MMX is recommended.

• Mathematically, quality of IEEE-1180 Reference > 64-bit Floating Point > 32-bit MMX/SSEMMX/SSE2MMX iDCT
  Reference iDCT implies lossless transformation for those who pursue for the limit.

• Depending on CPU types, DVD2AVI will choose the fast one among MMX/SSEMMX/SSE2MMX iDCT automatically.

Field Operation

• Forced FILM is designed for FILM or HYBRID (FILM XX%, NTSC XX%) source.
  For further information please refer to The Difference of Video Type.

• Swap Field Order change Top (Odd) Field First to Bottom (Even) Field First or vice versa
  Although VFAPI supports this function, however, it will pull down the decoding speed.
  Avoid swapping field order through VFAPI unless it's really necessary.

• Note that there is no absolute field order in FILM/HYBRID video.
  The TFF flag of the first frame decides the field order.
  You can check the field order by Info value (Top or Bottom field first) of Information Window.
  For example, in order to display smoothly on TV, bottom field first is always necessary for Canopus DV Codec.

Color Space

• This option influences the color space conversion of preview and AVI output.
  Most MPEG-2 streams are based on YUV 4:2:0 format.
  It's necessary to be converted to other popular format for display and edit.

• YUV 4:2:0 -> YUV 4:2:2 -> {DirectDraw YUY2 Overlay} -> Huffyuv, MPEG-4, DV
  YUV 4:2:0 -> YUV 4:2:2 -> YUV 4:4:4 -> RGB 24-bit -> {GDI Display} -> most codecs

• The processing of YUV 4:2:2 is much simple and faster than RGB 24-bit.
  However, it's not widely supported by video codecs and graphics adapters.

• Once YUY2 Overlay is supported on your system, DVD2AVI will switch to YUV 4:2:2 automatically.
  Otherwise you won't see anything when previewing by YUV 4:2:2.

• VFAPI is based on RGB 24-bit always (for maximum flexibility) no matter which option is selected.

YUV -> RGB

• Generally speaking, the color scale of TV and PC monitor is differnet.
  The RGB value of pure black on PC is (0, 0, 0) On the other hand, it's (16, 16, 16) on TV.
  If you want to watch the video on PC, it's better to choose PC Scale for full-scale colors.

• It's hard to decide which option is correct when you watch on TV.
  Video editors, encoders, and codecs all affect the color scale of the final result.
  Try both scale and compare them on TV to see which one is smiliar to original source.

• This option influences preview and AVI output of RGB 24-bit as well as VFAPI processing.
  You must switch the Color Space to RGB 24-bit in order to tell the difference.

Luminance Filter

• This filter is similiar to normal brightness/contrast filters which are based on RGB-Plane.
  It works on Y-Plane only (3X faster than RGB-plane) and pulls down less decoding speed.
  If you can't statisfy with the result, switch to color correction filters of other video editors.

Clip & Resize

• The more you clip, the faster the decoding speed is.
  It's better to clip (if necessary) by DVD2AVI before sending to other editors through VFAPI.

• There are some limitations on this filter due to MMX optimizations and field operations.
  The value of Left, Right, Top, and Bottom must be 2X (multiples of two)
  Left + Right and Top + Bottom both must be 8X.
  You should decide Left and Top at first and later modify Right and Bottom.

• The title bar of DVD2AVI shows possible multiples of the picture width and height.
  This multiple is very important for video codec processing.
  Some graphics adapters won't enable DirectDraw Display when watching MPEG4 unless it's [32X][16X].