Libav
Macros | Functions

Functions for working with pixel formats. More...

Macros

#define FF_LOSS_RESOLUTION   0x0001
 loss due to resolution change More...
 
#define FF_LOSS_DEPTH   0x0002
 loss due to color depth change More...
 
#define FF_LOSS_COLORSPACE   0x0004
 loss due to color space conversion More...
 
#define FF_LOSS_ALPHA   0x0008
 loss of alpha bits More...
 
#define FF_LOSS_COLORQUANT   0x0010
 loss due to color quantization More...
 
#define FF_LOSS_CHROMA   0x0020
 loss of chroma (e.g. More...
 

Functions

void attribute_deprecated avcodec_get_chroma_sub_sample (enum AVPixelFormat pix_fmt, int *h_shift, int *v_shift)
 
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. More...
 
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. More...
 
enum AVPixelFormat avcodec_find_best_pix_fmt2 (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. More...
 
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 4140 of file avcodec.h.

Referenced by avcodec_find_best_pix_fmt2(), and avcodec_get_pix_fmt_loss().

#define FF_LOSS_DEPTH   0x0002

loss due to color depth change

Definition at line 4141 of file avcodec.h.

Referenced by avcodec_find_best_pix_fmt2(), and avcodec_get_pix_fmt_loss().

#define FF_LOSS_COLORSPACE   0x0004

loss due to color space conversion

Definition at line 4142 of file avcodec.h.

Referenced by avcodec_find_best_pix_fmt2(), and avcodec_get_pix_fmt_loss().

#define FF_LOSS_ALPHA   0x0008

loss of alpha bits

Definition at line 4143 of file avcodec.h.

Referenced by avcodec_find_best_pix_fmt2(), and avcodec_get_pix_fmt_loss().

#define FF_LOSS_COLORQUANT   0x0010

loss due to color quantization

Definition at line 4144 of file avcodec.h.

Referenced by avcodec_find_best_pix_fmt2(), and avcodec_get_pix_fmt_loss().

#define FF_LOSS_CHROMA   0x0020

loss of chroma (e.g.

RGB to gray conversion)

Definition at line 4145 of file avcodec.h.

Referenced by avcodec_get_pix_fmt_loss().

Function Documentation

void attribute_deprecated avcodec_get_chroma_sub_sample ( enum AVPixelFormat  pix_fmt,
int *  h_shift,
int *  v_shift 
)
Deprecated:
Use av_pix_fmt_get_chroma_sub_sample

Definition at line 42 of file imgconvert.c.

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 175 of file raw.c.

Referenced by raw_encode_init(), 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_fmtdestination pixel format
[in]src_pix_fmtsource pixel format
[in]has_alphaWhether the source pixel format alpha channel is used.
Returns
Combination of flags informing you what kind of losses will occur.

Definition at line 54 of file imgconvert.c.

Referenced by avcodec_find_best_pix_fmt1(), and avcodec_find_best_pix_fmt2().

enum AVPixelFormat avcodec_find_best_pix_fmt2 ( 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_fmt2() 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_listAV_PIX_FMT_NONE terminated array of pixel formats to choose from
[in]src_pix_fmtsource pixel format
[in]has_alphaWhether the source pixel format alpha channel is used.
[out]loss_ptrCombination 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 128 of file imgconvert.c.

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

Definition at line 882 of file utils.c.

Referenced by avcodec_get_context_defaults3().