Resize¶
- resize.Bilinear(clip clip[, int width, int height, int format, enum matrix, enum transfer, enum primaries, enum range, enum chromaloc, enum matrix_in, enum transfer_in, enum primaries_in, enum range_in, enum chromaloc_in, float filter_param_a, float filter_param_b, string resample_filter_uv, float filter_param_a_uv, float filter_param_b_uv, string dither_type="none", string cpu_type, bint prefer_props=False, float src_left, float src_top, float src_width, float src_height, float nominal_luminance])¶
- resize.Bicubic(clip clip[, ...])¶
- resize.Point(clip clip[, ...])¶
- resize.Lanczos(clip clip[, ...])¶
- resize.Spline16(clip clip[, ...])¶
- resize.Spline36(clip clip[, ...])¶
- resize.Spline64(clip clip[, ...])¶
In VapourSynth the resizers have several functions. In addition to scaling, they also do colorspace conversions and conversions to and from the compat formats. Resize converts a clip of known or unknown format to another clip of known or unknown format, changing only the parameters specified by the user. The resize filters can handle varying size and format input clips and turn them into constant format clips.
If you do not know which resizer to choose, then try Bicubic. It usually makes a good neutral default.
Arguments denoted as type enum may be specified by numerical index (see ITU-T H.265 Annex E.3) or by name. Enums specified by name have their argument name suffixed with “_s”. For example, a destination matrix of BT 709 can be specified either with
matrix=1or withmatrix_s="709".Note that matrix is not an optional argument when converting to YUV. Also note that if no matrix is specified in an input YUV frame’s properties then matrix_in also needs to be set.
The function will return an error if the subsampling restrictions aren’t followed.
If you get an error like:
Resize error 3074: no path between colorspaces (2/2/2 => 1/1/1). May need to specify additional colorspace parameters.
It usually means the matrix/transfer/primaries are unknown and you have to specify the input colorspace paramaters yourself. Note: 2 means “unspecified” according to the ITU-T recommendation.
clip:
Accepts all kinds of input.
width, height:
Output image dimensions.
format:
Output format id.
matrix, transfer, primaries:
Output colorspace specification. If not provided, the corresponding attributes from the input clip will be selected, except for YCoCg and RGB color families, where the corresponding matrix is set by default.
range:
Output pixel range. For integer formats, this allows selection of the legal code values. Even when set, out of range values (BTB/WTW) may be generated. If the input format is of a different color family, the default range is studio/limited for YUV and full-range for RGB.
chromaloc:
Output chroma location. For subsampled formats, specifies the chroma location. If the input format is 4:4:4 or RGB and the output is subsampled, the default location is left-aligned, as per MPEG. Possible chroma locations (ITU-T H.265 Figure E.1): left, center, top_left, top, bottom_left, bottom
matrix_in, transfer_in, primaries_in, range_in, chromaloc_in:
Input colorspace/format specification. If the corresponding frame property is set to a value other than unspecified, the frame property is used instead of this parameter. Default values are set for certain color families. See the equivalent output arguments for more information. By default these override the corresponding frame properties if present, to instead give the frame properties precedence when both are present set prefer_props.
filter_param_a, filter_param_b:
Parameters for the scaler used for RGB and Y-channel. For the bicubic filter, filter_param_a/b represent the “b” and “c” parameters. For the lanczos filter, filter_param_a represents the number of taps.
resample_filter_uv:
Scaling method for UV channels. It defaults to the same as for the Y-channel. The following values can be used with resample_filter_uv: point, bilinear, bicubic, spline16, spline36, lanczos.
filter_param_a_uv, filter_param_b_uv:
Parameters for the scaler used for UV channels.
dither_type:
Dithering method. Dithering is used only for conversions resulting in an integer format. The following dithering methods are available: none, ordered, random, error_diffusion.
cpu_type:
Only used for testing.
prefer_props:
Determines whether frame properties or arguments take precedence when both are present. This option affects the matrix_in, transfer_in, primaries_in, range_in and chromaloc_in arguments and their frame property equivalents.
src_left, src_top, src_width, src_height:
Used to select the source region of the input to use. Can also be used to shift the image. Defaults to the whole image.
nominal_luminance:
Determines the physical brightness of the value 1.0. The unit is in cd/m^2.
To convert to YV12:
Bicubic(clip=clip, format=vs.YUV420P8, matrix_s="709")
To resize and convert YUV with color information frame properties to planar RGB:
Bicubic(clip=clip, width=1920, height=1080, format=vs.RGB24)
To resize and convert YUV without color information frame properties to planar RGB:
Bicubic(clip=clip, width=1920, height=1080, format=vs.RGB24, matrix_in_s="709")
The following tables list values of selected colorspace enumerations and their abbreviated names. (Numerical value in parentheses.) For all possible values, see ITU-T H.265.
Matrix coefficients (ITU-T H.265 Table E.5):
rgb (0) Identity The identity matrix. Typically used for GBR (often referred to as RGB); however, may also be used for YZX (often referred to as XYZ); 709 (1) KR = 0.2126; KB = 0.0722 ITU-R Rec. BT.709-5 unspec (2) Unspecified Image characteristics are unknown or are determined by the application. fcc (4) 470bg (5) KR = 0.299; KB = 0.114 ITU-R Rec. BT.470-6 System B, G (historical) (functionally the same as the value 6 (170m)) 170m (6) KR = 0.299; KB = 0.114 SMPTE 170M (2004) (functionally the same as the value 5 (470bg)) 240m (7) SMPTE 240M ycgco (8) YCgCo 2020ncl (9) KR = 0.2627; KB = 0.0593 Rec. ITU-R BT.2020 non-constant luminance system 2020cl (10) KR = 0.2627; KB = 0.0593 Rec. ITU-R BT.2020 constant luminance system chromancl (12) Chromaticity derived non-constant luminance system chromacl (13) Chromaticity derived constant luminance system ictcp (14) ICtCp
Transfer characteristics (ITU-T H.265 Table E.4):
709 (1) V = a * Lc0.45 - ( a - 1 ) for 1 >= Lc >= b V = 4.500 * Lc for b > Lc >= 0 Rec. ITU-R BT.709-5 (functionally the same as the values 6 (601), 14 (2020_10) and 15 (2020_12)) unspec (2) Unspecified Image characteristics are unknown or are determined by the application. 470m (4) ITU-R Rec. BT.470-6 System M 470bg (5) ITU-R Rec. BT.470-6 System B, G (historical) 601 (6) V = a * Lc0.45 - ( a - 1 ) for 1 >= Lc >= b V = 4.500 * Lc for b > Lc >= 0 Rec. ITU-R BT.601-6 525 or 625 (functionally the same as the values 1 (709), 14 (2020_10) and 15 (2020_12)) 240m (7) SMPTE 240M linear (8) V = Lc for all values of Lc Linear transfer characteristics log100 (9) Log 1:100 contrast log316 (10) Log 1:316 contrast xvycc (11) IEC 61966-2-4 srgb (13) IEC 61966-2-1 2020_10 (14) V = a * Lc0.45 - ( a - 1 ) for 1 >= Lc >= b V = 4.500 * Lc for b > Lc >= 0 Rec. ITU-R BT.2020 (functionally the same as the values 1 (709), 6 (601) and 15 (2020_12)) 2020_12 (15) V = a * Lc0.45 - ( a - 1 ) for 1 >= Lc >= b V = 4.500 * Lc for b > Lc >= 0 Rec. ITU-R BT.2020 (functionally the same as the values 1 (709), 6 (601) and 14 (2020_10)) st2084 (16) SMPTE ST 2084 std-b67 (18) ARIB std-b67
Color primaries (ITU-T H.265 Table E.3):
709 (1) primary x y green 0.300 0.600 blue 0.150 0.060 red 0.640 0.330 white D65 0.3127 0.3290 Rec. ITU-R BT.709-5 unspec (2) Unspecified Image characteristics are unknown or are determined by the application. 470m (4) ITU-R Rec. BT.470-6 System M 470bg (5) ITU-R Rec. BT.470-6 System B, G (historical) 170m (6) primary x y green 0.310 0.595 blue 0.155 0.070 red 0.630 0.340 white D65 0.3127 0.3290 SMPTE 170M (2004) (functionally the same as the value 7 (240m)) 240m (7) primary x y green 0.310 0.595 blue 0.155 0.070 red 0.630 0.340 white D65 0.3127 0.3290 SMPTE 240M (1999) (functionally the same as the value 6 (170m)) film (8) 2020 (9) primary x y green 0.170 0.797 blue 0.131 0.046 red 0.708 0.292 white D65 0.3127 0.3290 Rec. ITU-R BT.2020 st428 (10) Commonly known as xyz xyz (10) Alias for st428 st431-2 (11) DCI-P3 with traditional white point st432-1 (12) DCI-P3 jedec-p22 (22) E.B.U. STANDARD FOR CHROMATICITY TOLERANCES FOR STUDIO MONITORS (3213-E) Also known as JEDEC P22
Pixel range (ITU-T H.265 Eq E-4 to E-15):
limited (0) Studio (TV) legal range, 16-235 in 8 bits. Y = Clip1Y( Round( ( 1 << ( BitDepthY - 8 ) ) * ( 219 * E'Y + 16 ) ) ) Cb = Clip1C( Round( ( 1 << ( BitDepthC - 8 ) ) * ( 224 * E'PB + 128 ) ) ) Cr = Clip1C( Round( ( 1 << ( BitDepthC - 8 ) ) * ( 224 * E'PR + 128 ) ) ) R = Clip1Y( ( 1 << ( BitDepthY - 8 ) ) * ( 219 * E'R + 16 ) ) G = Clip1Y( ( 1 << ( BitDepthY - 8 ) ) * ( 219 * E'G + 16 ) ) B = Clip1Y( ( 1 << ( BitDepthY - 8 ) ) * ( 219 * E'B + 16 ) ) full (1) Full (PC) dynamic range, 0-255 in 8 bits. Y = Clip1Y( Round( ( ( 1 << BitDepthY ) - 1 ) * E'Y ) ) Cb = Clip1C( Round( ( ( 1 << BitDepthC ) - 1 ) * E'PB + ( 1 << ( BitDepthC - 1 ) ) ) ) Cr = Clip1C( Round( ( ( 1 << BitDepthC ) - 1 ) * E'PR + ( 1 << ( BitDepthC - 1 ) ) ) ) R = Clip1Y( ( ( 1 << BitDepthY ) - 1 ) * E'R ) G = Clip1Y( ( ( 1 << BitDepthY ) - 1 ) * E'G ) B = Clip1Y( ( ( 1 << BitDepthY ) - 1 ) * E'B )