Scaler Options
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The video scaler supports the following named options.

Options may be set by specifying -OPTION VALUE in the FFmpeg tools, with a few API-only exceptions noted below. For programmatic use, they can be set explicitly in the SwsContext options or through the libavutil/opt.h API.

sws_flags
     Set the scaler flags. This is also used to set the scaling algorithm. Only a single algorithm should be selected. Default value is bicubic.

     It accepts the following values:

     fast_bilinear
          Select fast bilinear scaling algorithm.

     bilinear
          Select bilinear scaling algorithm.

     bicubic
          Select bicubic scaling algorithm.

     experimental
          Select experimental scaling algorithm.

     neighbor
          Select nearest neighbor rescaling algorithm.

     area
          Select averaging area rescaling algorithm.

     bicublin
          Select bicubic scaling algorithm for the luma component, bilinear for chroma components.

     gauss
          Select Gaussian rescaling algorithm.

     sinc
          Select sinc rescaling algorithm.

     lanczos
          Select Lanczos rescaling algorithm. The default width (alpha) is 3 and can be changed by setting param0.

     spline
          Select natural bicubic spline rescaling algorithm.

     print_info
          Enable printing/debug logging.

     accurate_rnd
          Enable accurate rounding.

     full_chroma_int
          Enable full chroma interpolation.

     full_chroma_inp
          Select full chroma input.

     bitexact
          Enable bitexact output.

srcw (API ONLY)
     Set source width.

srch (API ONLY)
     Set source height.

dstw (API ONLY)
     Set destination width.

dsth (API ONLY)
     Set destination height.

src_format (API ONLY)
     Set source pixel format (must be expressed as an integer).

dst_format (API ONLY)
     Set destination pixel format (must be expressed as an integer).

src_range (BOOLEAN)
     If value is set to 1, indicates source is full range. Default value is 0, which indicates source is limited range.

dst_range (BOOLEAN)
     If value is set to 1, enable full range for destination. Default value is 0, which enables limited range.

param0, param1
     Set scaling algorithm parameters. The specified values are specific of some scaling algorithms and ignored by others. The specified values are floating point number values.

sws_dither
     Set the dithering algorithm. Accepts one of the following values. Default value is auto.

     auto
          automatic choice

     none
          no dithering

     bayer
          bayer dither

     ed
          error diffusion dither

     a_dither
          arithmetic dither, based using addition

     x_dither
          arithmetic dither, based using xor (more random/less apparent patterning that a_dither).

alphablend
     Set the alpha blending to use when the input has alpha but the output does not. Default value is none.

     uniform_color
          Blend onto a uniform background color

     checkerboard
          Blend onto a checkerboard

     none
          No blending