Convert

Revision as of 15:20, 16 January 2016

Convert between any of the color formats that AviSynth supports:

Color format	Image format	Chroma resolution
RGB24	interleaved	4:4:4 (full chroma)
RGB32	interleaved	4:4:4 (full chroma)
YV24	planar	4:4:4 (full chroma)
YV16	planar	4:2:2 (chroma shared between 2 pixels)
YUY2	interleaved	4:2:2 (chroma shared between 2 pixels)
YV12	planar	4:2:0 (chroma shared between 2x2 pixels)
YV411	planar	4:1:1 (chroma shared between 4 pixels)
Y8	(both)	4:0:0 (no chroma)

When the target format is the same as the source format, the original clip will be returned unchanged, except for the case of ConvertToYV12 where the ChromaInPlacement and ChromaOutPlacement parameters (see below) are different.

There is no unique way of converting YUV to RGB or vice-versa. There are different conversion matrices in use; the two most common ones are available in AviSynth, namely Rec.601 and Rec.709, plus some others. The following should be correct in most cases (see here for more)

• Rec.601 should be used when your source is standard definition (usually defined as smaller than 720p):

ConvertToRGB(clip) (using default "Rec601")

• Rec.709 should be used when your source is DVD or HDTV:

ConvertToRGB(clip, matrix="Rec709")

• The special-purpose matrices PC.601 and PC.709 keep the range unchanged,

instead of converting between 0-255 RGB and 16-235 YUV, as is the normal practice.

• The special-purpose matrix AVERAGE is used for (rarely found) sources with unweighted luma,

where Y = (R + G + B) / 3.

Use ConvertBackToYUY2 to convert back to YUY2 with minimal color-blurring when you have previously applied a YUY2→RGB conversion.

Syntax and Parameters

ConvertToRGB(clip [, string matrix, bool interlaced, string ChromaInPlacement, string chromaresample ] )
ConvertToRGB24(clip [, string matrix, bool interlaced, string ChromaInPlacement, string chromaresample ] )
ConvertToRGB32(clip [, string matrix, bool interlaced, string ChromaInPlacement, string chromaresample ] )
ConvertToYV24(clip [, bool interlaced, string matrix, string ChromaInPlacement, string chromaresample ] )
ConvertToYV16(clip [, bool interlaced, string matrix, string ChromaInPlacement, string chromaresample ] )
ConvertToYUY2(clip [, bool interlaced, string matrix, string ChromaInPlacement, string chromaresample ] )
ConvertToYV12(clip [, bool interlaced, string matrix, string ChromaInPlacement, string chromaresample, string ChromaOutPlacement ] )
ConvertToYV411(clip [, bool interlaced, string matrix, string ChromaInPlacement, string chromaresample ] )
ConvertToY8(clip [, string matrix ] )
ConvertBackToYUY2(clip [, string matrix ] )

string  matrix = "Rec601"

Controls the colour coefficients and scaling factors used in RGB↔YUV conversions.

• "Rec601" : Uses Rec.601 coefficients; scale full range [0..255] RGB to TV range [16..235] YUV, and vice versa.
• "Rec709" : Uses Rec.709 coefficients; scale full range [0..255] RGB to TV range [16..235] YUV, and vice versa.
• "PC.601" : Uses Rec.601 coefficients; keep range unchanged.
• "PC.709" : Uses Rec.709 coefficients; keep range unchanged.
• "AVERAGE" : Uses averaged coefficients (the luma becomes the average of the RGB channels); keep range unchanged.

bool  interlaced = false

If true, it is assumed that clip is interlaced; by default, it is assumed to be progressive.

This option is needed because for example, the following (assuming clip is interlaced YV12):

SeparateFields(clip)
ConvertToYUY2
Weave

...is upsampled incorrectly. Instead it is better to use:

ConvertToYUY2(clip, interlaced=true)

Note, interlaced=true has an effect only on YV12↔YUY2 or YV12↔RGB conversion. More about that can be found here.

string  ChromaInPlacement = "MPEG2"

Placement of the chroma samples in the clip. Can be one of these strings:

"MPEG2"	Subsampling used in MPEG-2 4:2:x and most other formats. Chroma samples are located on the left pixel column of the group (default).
"MPEG1"	Subsampling used in MPEG-1 4:2:0. Chroma samples are located on the center of each group of 4 pixels.
"DV"	Like MPEG-2, but U and V channels are “co-sited” vertically: V on the top row, and U on the bottom row. For 4:1:1, chroma is located on the leftmost column.

string  chromaresample = "bicubic"

Determines which chroma resampler is used in the conversion. It is only used when the chroma resolutions of the source and target are different. All AviSynth resizers are allowed ("point", "bilinear", "bicubic", "lanczos", "lanczos4", "blackman", "spline16", "spline36", "spline64", "gauss" and "sinc"). Default is "bicubic".

string  ChromaOutPlacement = "MPEG2"

Determines the output chroma placement in ConvertToYV12. See ChromaInPlacement.

Notes

Conversion paths

The chroma options ChromaInPlacement, chromaresample and ChromaOutPlacement options are only used in the 'planar conversion' part of the conversion path, and they process the chroma of the clip.

In v2.60 the following conversion paths occur:

• YUV planar → RGB via YV24
• YUV planar → YUY2 via YV16

(except for YV12 and chroma options listed above not explicitly set; in that case there is a direct conversion from YV12 to YUY2)

• RGB → YUV planar via YV24
• YUY2 → YUV planar via YV16

(except for YV12 and chroma options listed above not explicitly set; in that case there is a direct conversion from YUY2 to YV12)

Suppose you have a YUY2 clip for example and you convert it to YV24. The YUY2 will be converted to YV16 first without applying the chroma options. Then YV16 will be converted to YV24 while applying chromaresample. ChromaInPlacement and ChromaOutPlacement won't be used since YV12 is not involved.

Sampling

This page covers the sampling methods and color formats in more detail.

Color conversions

This page covers the color conversions in more detail.

Changelog