Functions for working with pixel formats. More...

Macros
#define	FF_LOSS_RESOLUTION 0x0001
	loss due to resolution change

#define	FF_LOSS_DEPTH 0x0002
	loss due to color depth change

#define	FF_LOSS_COLORSPACE 0x0004
	loss due to color space conversion

#define	FF_LOSS_ALPHA 0x0008
	loss of alpha bits

#define	FF_LOSS_COLORQUANT 0x0010
	loss due to color quantization

#define	FF_LOSS_CHROMA 0x0020
	loss of chroma (e.g.

Functions
void	avcodec_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.

unsigned int	avcodec_pix_fmt_to_codec_tag (enum AVPixelFormat pix_fmt)
	Return a value representing the fourCC code associated to the pixel format pix_fmt, or 0 if no associated fourCC code can be found.

int	avcodec_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.

enum AVPixelFormat	avcodec_find_best_pix_fmt_of_list (enum AVPixelFormat pix_fmt_list, enum AVPixelFormat src_pix_fmt, int has_alpha, int loss_ptr)
	Find the best pixel format to convert to given a certain source pixel format.

enum AVPixelFormat	avcodec_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)
	Find the best pixel format to convert to given a certain source pixel format and a selection of two destination pixel formats.

attribute_deprecated enum AVPixelFormat	avcodec_find_best_pix_fmt2 (enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2, enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr)

enum AVPixelFormat	avcodec_default_get_format (struct AVCodecContext s, const enum AVPixelFormat fmt)

Detailed Description

Functions for working with pixel formats.

Macro Definition Documentation

#define FF_LOSS_RESOLUTION 0x0001

loss due to resolution change

Definition at line 4690 of file avcodec.h.

Referenced by get_pix_fmt_score().

#define FF_LOSS_DEPTH 0x0002

loss due to color depth change

Definition at line 4691 of file avcodec.h.

Referenced by get_pix_fmt_score().

#define FF_LOSS_COLORSPACE 0x0004

loss due to color space conversion

Definition at line 4692 of file avcodec.h.

Referenced by get_pix_fmt_score().

#define FF_LOSS_ALPHA 0x0008

loss of alpha bits

Definition at line 4693 of file avcodec.h.

Referenced by avcodec_find_best_pix_fmt_of_2(), avcodec_get_pix_fmt_loss(), and get_pix_fmt_score().

#define FF_LOSS_COLORQUANT 0x0010

loss due to color quantization

Definition at line 4694 of file avcodec.h.

Referenced by get_pix_fmt_score().

#define FF_LOSS_CHROMA 0x0020

loss of chroma (e.g.

RGB to gray conversion)

Definition at line 4695 of file avcodec.h.

Referenced by get_pix_fmt_score().

Function Documentation

void avcodec_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.

This function asserts that pix_fmt is valid. See av_pix_fmt_get_chroma_sub_sample for one that returns a failure code and continues in case of invalid pix_fmts.

Parameters

[in]	pix_fmt	the pixel format
[out]	h_shift	store log2_chroma_h
[out]	v_shift	store log2_chroma_w

See Also: av_pix_fmt_get_chroma_sub_sample

Definition at line 65 of file imgconvert.c.

Referenced by alloc_buffer(), dirac_decode_data_unit(), encode_frame(), encode_init(), ff_mjpeg_decode_frame(), ff_MPV_common_init(), ff_MPV_encode_init(), ff_print_debug_info2(), j2kenc_init(), parse_source_parameters(), and vp3_decode_init().

unsigned int avcodec_pix_fmt_to_codec_tag ( enum AVPixelFormat pix_fmt )

Return a value representing the fourCC code associated to the pixel format pix_fmt, or 0 if no associated fourCC code can be found.

Definition at line 199 of file raw.c.

Referenced by avformat_find_stream_info(), raw_init_encoder(), and v4l2_read_header().

int avcodec_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. avcodec_get_fix_fmt_loss() informs you about the various types of losses which will occur when converting from one pixel format to another.

Parameters

[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.

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

Definition at line 207 of file imgconvert.c.

Referenced by avcodec_find_best_pix_fmt_of_2().

enum AVPixelFormat avcodec_find_best_pix_fmt_of_list	(	enum AVPixelFormat *	pix_fmt_list,
		enum AVPixelFormat	src_pix_fmt,
		int	has_alpha,
		int *	loss_ptr
	)

Find the best pixel format to convert to given a certain source pixel format.

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. avcodec_find_best_pix_fmt_of_2() searches which of the given pixel formats should be used to suffer the least amount of loss. The pixel formats from which it chooses one, are determined by the pix_fmt_list parameter.

Parameters

[in]	pix_fmt_list	AV_PIX_FMT_NONE terminated array of pixel formats to choose from
[in]	src_pix_fmt	source pixel format
[in]	has_alpha	Whether the source pixel format alpha channel is used.
[out]	loss_ptr	Combination of flags informing you what kind of losses will occur.

Returns: The best pixel format to convert to or -1 if none was found.

Definition at line 283 of file imgconvert.c.

enum AVPixelFormat avcodec_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
	)

Find the best pixel format to convert to given a certain source pixel format and a selection of two destination pixel formats.

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. avcodec_find_best_pix_fmt_of_2() selects which of the given pixel formats should be used to suffer the least amount of loss.

If one of the destination formats is AV_PIX_FMT_NONE the other pixel format (if valid) will be returned.

src_pix_fmt = AV_PIX_FMT_YUV420P;
dst_pix_fmt1= AV_PIX_FMT_RGB24;
dst_pix_fmt2= AV_PIX_FMT_GRAY8;
dst_pix_fmt3= AV_PIX_FMT_RGB8;
loss= FF_LOSS_CHROMA; // don't care about chroma loss, so chroma loss will be ignored.
dst_pix_fmt = avcodec_find_best_pix_fmt_of_2(dst_pix_fmt1, dst_pix_fmt2, src_pix_fmt, alpha, &loss);
dst_pix_fmt = avcodec_find_best_pix_fmt_of_2(dst_pix_fmt, dst_pix_fmt3, src_pix_fmt, alpha, &loss);

Parameters

[in]	dst_pix_fmt1	One of the two destination pixel formats to choose from
[in]	dst_pix_fmt2	The other of the two destination pixel formats to choose from
[in]	src_pix_fmt	Source pixel format
[in]	has_alpha	Whether the source pixel format alpha channel is used.
[in,out]	loss_ptr	Combination of loss flags. In: selects which of the losses to ignore, i.e. NULL or value of zero means we care about all losses. Out: the loss that occurs when converting from src to selected dst pixel format.

Returns: The best pixel format to convert to or -1 if none was found.

Definition at line 237 of file imgconvert.c.

Referenced by avcodec_find_best_pix_fmt2(), avcodec_find_best_pix_fmt_of_list(), choose_pixel_fmt(), and pick_format().

attribute_deprecated enum AVPixelFormat avcodec_find_best_pix_fmt2	(	enum AVPixelFormat	dst_pix_fmt1,
		enum AVPixelFormat	dst_pix_fmt2,
		enum AVPixelFormat	src_pix_fmt,
		int	has_alpha,
		int *	loss_ptr
	)

Definition at line 276 of file imgconvert.c.

enum AVPixelFormat avcodec_default_get_format	(	struct AVCodecContext *	s,
		const enum AVPixelFormat *	fmt
	)

Definition at line 697 of file utils.c.

Referenced by avcodec_get_context_defaults3().

Macros

Functions

Detailed Description

Macro Definition Documentation

Function Documentation