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DVD 704-Wide Non-Pan-Scan Example

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The use of MPEG-2 on DVD for 704-wide pictures requires a source rectangle that exceeds the boundaries of the decoded picture (if using the method described in MPEG-2 Pan-Scan Example). In this case, the DVD specifies a display_horizontal_size of 720 that exceeds the decoded picture's horizontal_size of 704. When the source rectangle exceeds the boundaries of the decoded picture, the host software decoder is responsible for cropping the source rectangle to keep it from reaching outside the allocated source area and for managing the destination rectangle to adjust for the cropping.

The source rectangle is defined by the PictureSourceRect16thPel member of the DXVA_BlendCombination structure (in one-sixteenth of a luminance sample spacing resolution) with the following values:

  • left = 0

  • right = 16 X (left + horizontal_size) = 11264

The picture destination rectangle is defined by the PictureDestinationRect member of the DXVA_BlendCombination structure (in one-sixteenth of a luminance sample spacing resolution) by one of the following two alternatives:

  1. A rectangle with the following values:

    • left = (display_horizontal_size − horizontal_size) / 2 = 8
    • right = left + horizontal_size = 712

  2. A rectangle with the following values:

    • left = 0
    • right = left + horizontal_size = 704

In the second case, the rectangle indicated by the GraphicDestinationRect member of the DXVA_BlendCombination structure is displaced to the left by eight samples to compensate for the shifted picture destination.

The second of these two alternatives creates only the destination area that is used for the display.