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Both of these dithering methods are from http://pippin.gimp.org/a_dither/ for GIF they can be considered better than bayer (provides more gray-levels), and spatial stability - often more than twice as good compression and less visual flicker than error diffusion methods (the methods also avoids error-shadow artifacts of diffusion dithers). These methods are similar to blue/green noise type dither masks; but are simple enough to generate their mask on the fly. They are still research work in progress; though more expensive to generate masks (which can be used in a LUT) like 'void and cluster' and similar methods will yield superior results
128 lines
2.4 KiB
Plaintext
128 lines
2.4 KiB
Plaintext
@anchor{scaler_options}
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@chapter Scaler Options
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@c man begin SCALER OPTIONS
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The video scaler supports the following named options.
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Options may be set by specifying -@var{option} @var{value} in the
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FFmpeg tools. For programmatic use, they can be set explicitly in the
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@code{SwsContext} options or through the @file{libavutil/opt.h} API.
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@table @option
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@anchor{sws_flags}
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@item sws_flags
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Set the scaler flags. This is also used to set the scaling
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algorithm. Only a single algorithm should be selected.
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It accepts the following values:
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@table @samp
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@item fast_bilinear
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Select fast bilinear scaling algorithm.
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@item bilinear
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Select bilinear scaling algorithm.
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@item bicubic
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Select bicubic scaling algorithm.
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@item experimental
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Select experimental scaling algorithm.
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@item neighbor
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Select nearest neighbor rescaling algorithm.
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@item area
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Select averaging area rescaling algorithm.
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@item bicublin
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Select bicubic scaling algorithm for the luma component, bilinear for
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chroma components.
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@item gauss
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Select Gaussian rescaling algorithm.
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@item sinc
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Select sinc rescaling algorithm.
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@item lanczos
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Select lanczos rescaling algorithm.
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@item spline
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Select natural bicubic spline rescaling algorithm.
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@item print_info
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Enable printing/debug logging.
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@item accurate_rnd
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Enable accurate rounding.
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@item full_chroma_int
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Enable full chroma interpolation.
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@item full_chroma_inp
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Select full chroma input.
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@item bitexact
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Enable bitexact output.
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@end table
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@item srcw
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Set source width.
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@item srch
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Set source height.
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@item dstw
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Set destination width.
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@item dsth
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Set destination height.
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@item src_format
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Set source pixel format (must be expressed as an integer).
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@item dst_format
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Set destination pixel format (must be expressed as an integer).
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@item src_range
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Select source range.
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@item dst_range
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Select destination range.
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@item param0, param1
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Set scaling algorithm parameters. The specified values are specific of
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some scaling algorithms and ignored by others. The specified values
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are floating point number values.
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@item sws_dither
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Set the dithering algorithm. Accepts one of the following
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values. Default value is @samp{auto}.
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@table @samp
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@item auto
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automatic choice
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@item none
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no dithering
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@item bayer
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bayer dither
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@item ed
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error diffusion dither
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@item a_dither
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arithmetic dither, based using addition
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@item x_dither
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arithmetic dither, based using xor (more random/less apparent patterning that
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a_dither).
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@end table
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@end table
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@c man end SCALER OPTIONS
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