Файл pixdesc.h

См. исходные тексты.

Классы
struct	AVComponentDescriptor
struct	AVPixFmtDescriptor

Определения типов
typedef struct AVComponentDescriptor	AVComponentDescriptor
typedef struct AVPixFmtDescriptor	AVPixFmtDescriptor

Функции
int	av_get_bits_per_pixel (const AVPixFmtDescriptor *pixdesc)
int	av_get_padded_bits_per_pixel (const AVPixFmtDescriptor *pixdesc)
const AVPixFmtDescriptor *	av_pix_fmt_desc_get (enum AVPixelFormat pix_fmt)
const AVPixFmtDescriptor *	av_pix_fmt_desc_next (const AVPixFmtDescriptor *prev)
enum AVPixelFormat	av_pix_fmt_desc_get_id (const AVPixFmtDescriptor *desc)
int	av_pix_fmt_get_chroma_sub_sample (enum AVPixelFormat pix_fmt, int *h_shift, int *v_shift)
int	av_pix_fmt_count_planes (enum AVPixelFormat pix_fmt)
const char *	av_color_range_name (enum AVColorRange range)
int	av_color_range_from_name (const char *name)
const char *	av_color_primaries_name (enum AVColorPrimaries primaries)
int	av_color_primaries_from_name (const char *name)
const char *	av_color_transfer_name (enum AVColorTransferCharacteristic transfer)
int	av_color_transfer_from_name (const char *name)
const char *	av_color_space_name (enum AVColorSpace space)
int	av_color_space_from_name (const char *name)
const char *	av_chroma_location_name (enum AVChromaLocation location)
int	av_chroma_location_from_name (const char *name)
enum AVPixelFormat	av_get_pix_fmt (const char *name)
const char *	av_get_pix_fmt_name (enum AVPixelFormat pix_fmt)
char *	av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt)
void	av_read_image_line2 (void *dst, const uint8_t *data[4], const int linesize[4], const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component, int dst_element_size)
void	av_read_image_line (uint16_t *dst, const uint8_t *data[4], const int linesize[4], const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component)
void	av_write_image_line2 (const void *src, uint8_t *data[4], const int linesize[4], const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int src_element_size)
void	av_write_image_line (const uint16_t *src, uint8_t *data[4], const int linesize[4], const AVPixFmtDescriptor *desc, int x, int y, int c, int w)
enum AVPixelFormat	av_pix_fmt_swap_endianness (enum AVPixelFormat pix_fmt)
int	av_get_pix_fmt_loss (enum AVPixelFormat dst_pix_fmt, enum AVPixelFormat src_pix_fmt, int has_alpha)
enum AVPixelFormat	av_find_best_pix_fmt_of_2 (enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2, enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr)

Типы

AVComponentDescriptor

typedef struct AVComponentDescriptor AVComponentDescriptor

AVPixFmtDescriptor

typedef struct AVPixFmtDescriptor AVPixFmtDescriptor

Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes of an image. It also stores the subsampling factors and number of components.

Заметки

This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV and all the YUV variants) AVPixFmtDescriptor just stores how values are stored not what these values represent.

Функции

av_get_bits_per_pixel()

int av_get_bits_per_pixel

(

const AVPixFmtDescriptor *

pixdesc

)

Return the number of bits per pixel used by the pixel format described by pixdesc. Note that this is not the same as the number of bits per sample.

The returned number of bits refers to the number of bits actually used for storing the pixel information, that is padding bits are not counted.

av_get_padded_bits_per_pixel()

int av_get_padded_bits_per_pixel

(

const AVPixFmtDescriptor *

pixdesc

)

Return the number of bits per pixel for the pixel format described by pixdesc, including any padding or unused bits.

av_pix_fmt_desc_get()

const AVPixFmtDescriptor* av_pix_fmt_desc_get

(

enum AVPixelFormat

pix_fmt

)

Возвращает

a pixel format descriptor for provided pixel format or NULL if this pixel format is unknown.

av_pix_fmt_desc_next()

const AVPixFmtDescriptor* av_pix_fmt_desc_next

(

const AVPixFmtDescriptor *

prev

)

Iterate over all pixel format descriptors known to libavutil.

Аргументы

prev	previous descriptor. NULL to get the first descriptor.

Возвращает

next descriptor or NULL after the last descriptor

av_pix_fmt_desc_get_id()

enum AVPixelFormat av_pix_fmt_desc_get_id

(

const AVPixFmtDescriptor *

desc

)

Возвращает

an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc is not a valid pointer to a pixel format descriptor.

av_pix_fmt_get_chroma_sub_sample()

int av_pix_fmt_get_chroma_sub_sample	(	enum AVPixelFormat	pix_fmt,
		int *	h_shift,
		int *	v_shift
	)

Utility function to access log2_chroma_w log2_chroma_h from the pixel format AVPixFmtDescriptor.

Аргументы

[in]	pix_fmt	the pixel format
[out]	h_shift	store log2_chroma_w (horizontal/width shift)
[out]	v_shift	store log2_chroma_h (vertical/height shift)

Возвращает

0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format

av_pix_fmt_count_planes()

int av_pix_fmt_count_planes

(

enum AVPixelFormat

pix_fmt

)

Возвращает

number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a valid pixel format.

av_color_range_name()

const char* av_color_range_name

(

enum AVColorRange

range

)

Возвращает

the name for provided color range or NULL if unknown.

av_color_range_from_name()

int av_color_range_from_name

(

const char *

name

)

Возвращает

the AVColorRange value for name or an AVError if not found.

av_color_primaries_name()

const char* av_color_primaries_name

(

enum AVColorPrimaries

primaries

)

Возвращает

the name for provided color primaries or NULL if unknown.

av_color_primaries_from_name()

int av_color_primaries_from_name

(

const char *

name

)

Возвращает

the AVColorPrimaries value for name or an AVError if not found.

av_color_transfer_name()

const char* av_color_transfer_name

(

enum AVColorTransferCharacteristic

transfer

)

Возвращает

the name for provided color transfer or NULL if unknown.

av_color_transfer_from_name()

int av_color_transfer_from_name

(

const char *

name

)

Возвращает

the AVColorTransferCharacteristic value for name or an AVError if not found.

av_color_space_name()

const char* av_color_space_name

(

enum AVColorSpace

space

)

Возвращает

the name for provided color space or NULL if unknown.

av_color_space_from_name()

int av_color_space_from_name

(

const char *

name

)

Возвращает

the AVColorSpace value for name or an AVError if not found.

av_chroma_location_name()

const char* av_chroma_location_name

(

enum AVChromaLocation

location

)

Возвращает

the name for provided chroma location or NULL if unknown.

av_chroma_location_from_name()

int av_chroma_location_from_name

(

const char *

name

)

Возвращает

the AVChromaLocation value for name or an AVError if not found.

av_get_pix_fmt()

enum AVPixelFormat av_get_pix_fmt

(

const char *

name

)

Return the pixel format corresponding to name.

If there is no pixel format with name name, then looks for a pixel format with the name corresponding to the native endian format of name. For example in a little-endian system, first looks for "gray16", then for "gray16le".

Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.

av_get_pix_fmt_name()

const char* av_get_pix_fmt_name

(

enum AVPixelFormat

pix_fmt

)

Return the short name for a pixel format, NULL in case pix_fmt is unknown.

См. также

av_get_pix_fmt(), av_get_pix_fmt_string()

av_get_pix_fmt_string()

char* av_get_pix_fmt_string	(	char *	buf,
		int	buf_size,
		enum AVPixelFormat	pix_fmt
	)

Print in buf the string corresponding to the pixel format with number pix_fmt, or a header if pix_fmt is negative.

Аргументы

buf	the buffer where to write the string
buf_size	the size of buf
pix_fmt	the number of the pixel format to print the corresponding info string, or a negative value to print the corresponding header.

av_read_image_line2()

void av_read_image_line2	(	void *	dst,
		const uint8_t *	data[4],
		const int	linesize[4],
		const AVPixFmtDescriptor *	desc,
		int	x,
		int	y,
		int	c,
		int	w,
		int	read_pal_component,
		int	dst_element_size
	)

Read a line from an image, and write the values of the pixel format component c to dst.

Аргументы

data	the array containing the pointers to the planes of the image
linesize	the array containing the linesizes of the image
desc	the pixel format descriptor for the image
x	the horizontal coordinate of the first pixel to read
y	the vertical coordinate of the first pixel to read
w	the width of the line to read, that is the number of values to write to dst
read_pal_component	if not zero and the format is a paletted format writes the values corresponding to the palette component c in data[1] to dst, rather than the palette indexes in data[0]. The behavior is undefined if the format is not paletted.
dst_element_size	size of elements in dst array (2 or 4 byte)

av_read_image_line()

void av_read_image_line	(	uint16_t *	dst,
		const uint8_t *	data[4],
		const int	linesize[4],
		const AVPixFmtDescriptor *	desc,
		int	x,
		int	y,
		int	c,
		int	w,
		int	read_pal_component
	)

av_write_image_line2()

void av_write_image_line2	(	const void *	src,
		uint8_t *	data[4],
		const int	linesize[4],
		const AVPixFmtDescriptor *	desc,
		int	x,
		int	y,
		int	c,
		int	w,
		int	src_element_size
	)

Write the values from src to the pixel format component c of an image line.

Аргументы

src	array containing the values to write
data	the array containing the pointers to the planes of the image to write into. It is supposed to be zeroed.
linesize	the array containing the linesizes of the image
desc	the pixel format descriptor for the image
x	the horizontal coordinate of the first pixel to write
y	the vertical coordinate of the first pixel to write
w	the width of the line to write, that is the number of values to write to the image line
src_element_size	size of elements in src array (2 or 4 byte)

av_write_image_line()

void av_write_image_line	(	const uint16_t *	src,
		uint8_t *	data[4],
		const int	linesize[4],
		const AVPixFmtDescriptor *	desc,
		int	x,
		int	y,
		int	c,
		int	w
	)

av_pix_fmt_swap_endianness()

enum AVPixelFormat av_pix_fmt_swap_endianness

(

enum AVPixelFormat

pix_fmt

)

Utility function to swap the endianness of a pixel format.

Аргументы

[in]

pix_fmt

the pixel format

Возвращает

pixel format with swapped endianness if it exists, otherwise AV_PIX_FMT_NONE

av_get_pix_fmt_loss()

int av_get_pix_fmt_loss	(	enum AVPixelFormat	dst_pix_fmt,
		enum AVPixelFormat	src_pix_fmt,
		int	has_alpha
	)

Compute what kind of losses will occur when converting from one specific pixel format to another. When converting from one pixel format to another, information loss may occur. For example, when converting from RGB24 to GRAY, the color information will be lost. Similarly, other losses occur when converting from some formats to other formats. These losses can involve loss of chroma, but also loss of resolution, loss of color depth, loss due to the color space conversion, loss of the alpha bits or loss due to color quantization. av_get_fix_fmt_loss() informs you about the various types of losses which will occur when converting from one pixel format to another.

Аргументы

[in]	dst_pix_fmt	destination pixel format
[in]	src_pix_fmt	source pixel format
[in]	has_alpha	Whether the source pixel format alpha channel is used.

Возвращает

Combination of flags informing you what kind of losses will occur (maximum loss for an invalid dst_pix_fmt).

av_find_best_pix_fmt_of_2()

enum AVPixelFormat av_find_best_pix_fmt_of_2	(	enum AVPixelFormat	dst_pix_fmt1,
		enum AVPixelFormat	dst_pix_fmt2,
		enum AVPixelFormat	src_pix_fmt,
		int	has_alpha,
		int *	loss_ptr
	)

Compute what kind of losses will occur when converting from one specific pixel format to another. When converting from one pixel format to another, information loss may occur. For example, when converting from RGB24 to GRAY, the color information will be lost. Similarly, other losses occur when converting from some formats to other formats. These losses can involve loss of chroma, but also loss of resolution, loss of color depth, loss due to the color space conversion, loss of the alpha bits or loss due to color quantization. av_get_fix_fmt_loss() informs you about the various types of losses which will occur when converting from one pixel format to another.

Аргументы

[in]	dst_pix_fmt	destination pixel format
[in]	src_pix_fmt	source pixel format
[in]	has_alpha	Whether the source pixel format alpha channel is used.

Возвращает

Combination of flags informing you what kind of losses will occur (maximum loss for an invalid dst_pix_fmt).