1@anchor{scaler_options} 2@chapter Scaler Options 3@c man begin SCALER OPTIONS 4 5The video scaler supports the following named options. 6 7Options may be set by specifying -@var{option} @var{value} in the 8FFmpeg tools, with a few API-only exceptions noted below. 9For programmatic use, they can be set explicitly in the 10@code{SwsContext} options or through the @file{libavutil/opt.h} API. 11 12@table @option 13 14@anchor{sws_flags} 15@item sws_flags 16Set the scaler flags. This is also used to set the scaling 17algorithm. Only a single algorithm should be selected. Default 18value is @samp{bicubic}. 19 20It accepts the following values: 21@table @samp 22@item fast_bilinear 23Select fast bilinear scaling algorithm. 24 25@item bilinear 26Select bilinear scaling algorithm. 27 28@item bicubic 29Select bicubic scaling algorithm. 30 31@item experimental 32Select experimental scaling algorithm. 33 34@item neighbor 35Select nearest neighbor rescaling algorithm. 36 37@item area 38Select averaging area rescaling algorithm. 39 40@item bicublin 41Select bicubic scaling algorithm for the luma component, bilinear for 42chroma components. 43 44@item gauss 45Select Gaussian rescaling algorithm. 46 47@item sinc 48Select sinc rescaling algorithm. 49 50@item lanczos 51Select Lanczos rescaling algorithm. The default width (alpha) is 3 and can be 52changed by setting @code{param0}. 53 54@item spline 55Select natural bicubic spline rescaling algorithm. 56 57@item print_info 58Enable printing/debug logging. 59 60@item accurate_rnd 61Enable accurate rounding. 62 63@item full_chroma_int 64Enable full chroma interpolation. 65 66@item full_chroma_inp 67Select full chroma input. 68 69@item bitexact 70Enable bitexact output. 71@end table 72 73@item srcw @var{(API only)} 74Set source width. 75 76@item srch @var{(API only)} 77Set source height. 78 79@item dstw @var{(API only)} 80Set destination width. 81 82@item dsth @var{(API only)} 83Set destination height. 84 85@item src_format @var{(API only)} 86Set source pixel format (must be expressed as an integer). 87 88@item dst_format @var{(API only)} 89Set destination pixel format (must be expressed as an integer). 90 91@item src_range @var{(boolean)} 92If value is set to @code{1}, indicates source is full range. Default value is 93@code{0}, which indicates source is limited range. 94 95@item dst_range @var{(boolean)} 96If value is set to @code{1}, enable full range for destination. Default value 97is @code{0}, which enables limited range. 98 99@anchor{sws_params} 100@item param0, param1 101Set scaling algorithm parameters. The specified values are specific of 102some scaling algorithms and ignored by others. The specified values 103are floating point number values. 104 105@item sws_dither 106Set the dithering algorithm. Accepts one of the following 107values. Default value is @samp{auto}. 108 109@table @samp 110@item auto 111automatic choice 112 113@item none 114no dithering 115 116@item bayer 117bayer dither 118 119@item ed 120error diffusion dither 121 122@item a_dither 123arithmetic dither, based using addition 124 125@item x_dither 126arithmetic dither, based using xor (more random/less apparent patterning that 127a_dither). 128 129@end table 130 131@item alphablend 132Set the alpha blending to use when the input has alpha but the output does not. 133Default value is @samp{none}. 134 135@table @samp 136@item uniform_color 137Blend onto a uniform background color 138 139@item checkerboard 140Blend onto a checkerboard 141 142@item none 143No blending 144 145@end table 146 147@end table 148 149@c man end SCALER OPTIONS 150