Color handling

Macros
#define	BC_RGB565   2
#define	BC_BGR565   3
#define	BC_BGR888   4
#define	BC_BGR8888   5
#define	BC_RGB888   6
#define	BC_RGBA8888   7
#define	BC_RGB161616   8
#define	BC_RGBA16161616   9
#define	BC_YUVA8888   10
#define	BC_YUV422   13
#define	BC_YUV420P   14
#define	BC_YUV422P   15
#define	BC_YUV444P   16
#define	BC_YUV411P   17
#define	BC_YUVJ420P   18
#define	BC_YUVJ422P   19
#define	BC_YUVJ444P   20
#define	BC_YUV422P16   21
#define	BC_YUV444P16   22
#define	BC_YUV422P10   23
#define	BC_YUVJ422P10   24
#define	LQT_COLORMODEL_NONE   -1

Functions
const char *	lqt_colormodel_to_string (int colormodel)
	Convert a colormodel to a human readable string.
int	lqt_string_to_colormodel (const char *str)
	Convert a description string to a colormodel.
int	lqt_colormodel_is_planar (int colormodel)
	Check if a colormodel is planar.
int	lqt_colormodel_has_alpha (int colormodel)
	Check if a colormodel has an alpha (transperency) channel.
int	lqt_colormodel_is_rgb (int colormodel)
	Check, if a colormodel is RGB based.
int	lqt_colormodel_is_yuv (int colormodel)
	Check, if a colormodel is YUV based.
void	lqt_colormodel_get_chroma_sub (int colormodel, int *sub_h, int *sub_v)
	Get the chroma subsampling factors.
void	lqt_get_default_rowspan (int colormodel, int width, int *rowspan, int *rowspan_uv)
	Get the default row span for a colormodel and an image width.
int	lqt_colormodel_has_conversion (int in_cmodel, int out_cmodel)
	Check if a colormodel conversion is supported by libquicktime.
int	lqt_num_colormodels ()
	Get number of supported colormodels.
const char *	lqt_get_colormodel_string (int index)
	Get a colormodel string.
int	lqt_get_colormodel (int index)
	Get a colormodel.
int	lqt_get_best_source_colormodel (int const *source_options, int target)
	Select a source colormodel from a provided list that is best for conversion into a specified target colormodel.
int	lqt_get_best_target_colormodel (int source, int const *target_options)
	Select a target colormodel from a provided list that is best for conversion from a specified source colormodel.

---

Detailed Description

Libquicktime has a built in colormodel converter, which can do implicit colormodel conversions while en-/decoding. It is, however, far from perfect: It is incomplete (i.e. not all conversions are present), slow and sometimes inaccurate. Therefore, there is a possibility to bypass internal colormodel conversions.

---

Macro Definition Documentation

#define BC_RGB565   2

16 bit RGB. Each pixel is a uint16_t in native byte order. Color masks are: for red: 0xf800, for green: 0x07e0, for blue: 0x001f

#define BC_BGR565   3

16 bit BGR. Each pixel is a uint16_t in native byte order. Color masks are: for red: 0x001f, for green: 0x07e0, for blue: 0xf800

#define BC_BGR888   4

24 bit BGR. Each color is an uint8_t. Color order is BGR

#define BC_BGR8888   5

32 bit BGR. Each color is an uint8_t. Color order is BGRXBGRX, where X is unused

#define BC_RGB888   6

24 bit RGB. Each color is an uint8_t. Color order is RGB

#define BC_RGBA8888   7

32 bit RGBA. Each color is an uint8_t. Color order is RGBARGBA

#define BC_RGB161616   8

48 bit RGB. Each color is an uint16_t in native byte order. Color order is RGB

#define BC_RGBA16161616   9

64 bit RGBA. Each color is an uint16_t in native byte order. Color order is RGBA

#define BC_YUVA8888   10

Packed YCbCrA 4:4:4:4. Each component is an uint8_t. Component order is YUVA

#define BC_YUV422   13

Packed YCbCr 4:2:2. Each component is an uint8_t. Component order is Y1 U1 Y2 V1

#define BC_YUV420P   14

Planar YCbCr 4:2:0. Each component is an uint8_t. Chroma placement is defined by lqt_chroma_placement_t

#define BC_YUV422P   15

Planar YCbCr 4:2:2. Each component is an uint8_t

#define BC_YUV444P   16

Planar YCbCr 4:4:4. Each component is an uint8_t

#define BC_YUV411P   17

Planar YCbCr 4:1:1. Each component is an uint8_t

#define BC_YUVJ420P   18

Planar YCbCr 4:2:0. Each component is an uint8_t, luma and chroma values are full range (0x00 .. 0xff)

#define BC_YUVJ422P   19

Planar YCbCr 4:2:2. Each component is an uint8_t, luma and chroma values are full range (0x00 .. 0xff)

#define BC_YUVJ444P   20

Planar YCbCr 4:4:4. Each component is an uint8_t, luma and chroma values are full range (0x00 .. 0xff)

#define BC_YUV422P16   21

16 bit Planar YCbCr 4:2:2. Each component is an uint16_t in native byte order.

#define BC_YUV444P16   22

16 bit Planar YCbCr 4:4:4. Each component is an uint16_t in native byte order.

#define BC_YUV422P10   23

10 bit values in uint16_t native byte order containers, planar YCbCr 4:2:2.

#define BC_YUVJ422P10   24

10 bit values in uint16_t native byte order containers, planar YCbCr 4:2:2. Luma and chroma values are full range (0 .. 1023)

#define LQT_COLORMODEL_NONE   -1

This value is used for termination of colormodel arrays

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Function Documentation

const char* lqt_colormodel_to_string

(

int

colormodel

)

Convert a colormodel to a human readable string.

Parameters:

colormodel

A colormodel

Returns:

A description of the colormodel

int lqt_string_to_colormodel

(

const char *

str

)

Convert a description string to a colormodel.

Parameters:

str	A colormodel description (as returned by lqt_colormodel_to_string)

Returns:

The corresponding colormodel or LQT_COLORMODEL_NONE

int lqt_colormodel_is_planar

(

int

colormodel

)

Check if a colormodel is planar.

Parameters:

colormodel

A colormodel

Returns:

1 if the colormodel is planar, 0 else

int lqt_colormodel_has_alpha

(

int

colormodel

)

Check if a colormodel has an alpha (transperency) channel.

Parameters:

colormodel

A colormodel

Returns:

1 if the colormodel has an alpha channel, 0 else

int lqt_colormodel_is_rgb

(

int

colormodel

)

Check, if a colormodel is RGB based.

Parameters:

colormodel

A colormodel

Returns:

1 if the colormodel is RGB based, 0 else

int lqt_colormodel_is_yuv

(

int

colormodel

)

Check, if a colormodel is YUV based.

Parameters:

colormodel

A colormodel

Returns:

1 if the colormodel is YUV based, 0 else

void lqt_colormodel_get_chroma_sub	(	int	colormodel,
		int *	sub_h,
		int *	sub_v
	)

Get the chroma subsampling factors.

Parameters:

colormodel	A colormodel
sub_h	Returns the horizontal subsampling factor
sub_v	Returns the vertical subsampling factor

void lqt_get_default_rowspan	(	int	colormodel,
		int	width,
		int *	rowspan,
		int *	rowspan_uv
	)

Get the default row span for a colormodel and an image width.

Parameters:

colormodel	A colormodel
width	Image width
rowspan	Returns the rowspan for the luminance (Y) plane
rowspan_uv	Returns the rowspan for the chrominance (U/V) planes

The rowspan is the byte offset between scanlines. It can be calculated from the colormodel and the image width. Some APIs however, padd the scanlines to certain boundaries, so the rowspans might become larger here (see lqt_set_row_span and lqt_set_row_span_uv).

int lqt_colormodel_has_conversion	(	int	in_cmodel,
		int	out_cmodel
	)

Check if a colormodel conversion is supported by libquicktime.

Parameters:

in_cmodel	Input colormodel
out_cmodel	Output colormodel

Returns:

1 if the requested conversion is possible, 0 else

As noted before, the colormodel converter is not complete, and this function checks it. As a fallback, conversions from and to BC_RGB888 are always supported. If you need a converison, which is not present, contact the authors for hints how to write it :)

int lqt_num_colormodels

(

)

Get number of supported colormodels.

Returns:

The number of colormodels known to your version of libquicktime

const char* lqt_get_colormodel_string

(

int

index

)

Get a colormodel string.

Parameters:

index

Index of the colormodel (between 0 and the return value of lqt_num_colormodels - 1)

Returns:

A description of the colormodel according to index or NULL.

int lqt_get_colormodel

(

int

index

)

Get a colormodel.

Parameters:

index

Index of the colormodel (between 0 and the return value of lqt_num_colormodels - 1)

Returns:

The colormodel according to index or LQT_COLORMODEL_NONE

int lqt_get_best_source_colormodel	(	int const *	source_options,
		int	target
	)

Select a source colormodel from a provided list that is best for conversion into a specified target colormodel.

Parameters:

source_options	An array of source colormodels to select from. Must be terminated with LQT_COLORMODEL_NODE.
target	The target colormodel.

Returns:

A colormodel from source_options or LQT_COLORMODEL_NONE, if none of the source colormodels can be converted to the target one.

int lqt_get_best_target_colormodel	(	int	source,
		int const *	target_options
	)

Select a target colormodel from a provided list that is best for conversion from a specified source colormodel.

Parameters:

source	The source colormodel.
target_options	An array of target colormodels to select from. Must be terminated with LQT_COLORMODEL_NODE.

Returns:

A colormodel from target_options or LQT_COLORMODEL_NONE, if the source colormodel can't be converted to any of the target ones.