GstVideoChroma: GStreamer Base Plugins 1.0 Library Reference Manual

GstVideoChroma

GstVideoChroma — Functions and utility object for operating on chroma video planes

Functions

GstVideoChromaSite	gst_video_chroma_from_string ()
const gchar *	gst_video_chroma_to_string ()
void	gst_video_chroma_resample ()
void	gst_video_chroma_resample_free ()
void	gst_video_chroma_resample_get_info ()
GstVideoChromaResample *	gst_video_chroma_resample_new ()

Types and Values

enum	GstVideoChromaSite
enum	GstVideoChromaFlags
enum	GstVideoChromaMethod
	GstVideoChromaResample

Includes

#include <gst/video/video-chroma.h>

Description

The functions gst_video_chroma_from_string() and gst_video_chroma_to_string() convert between GstVideoChromaSite and string descriptions.

GstVideoChromaResample is a utility object for resampling chroma planes and converting between different chroma sampling sitings.

Functions

gst_video_chroma_from_string ()

GstVideoChromaSite
gst_video_chroma_from_string (const gchar *s);

Convert s to a GstVideoChromaSite

Parameters

a chromasite string

Returns

a GstVideoChromaSite or GST_VIDEO_CHROMA_SITE_UNKNOWN when s does not contain a valid chroma description.

gst_video_chroma_to_string ()

const gchar *
gst_video_chroma_to_string (GstVideoChromaSite site);

Converts site to its string representation.

Parameters

site

a GstVideoChromaSite

Returns

a string describing site .

gst_video_chroma_resample ()

void
gst_video_chroma_resample (GstVideoChromaResample *resample,
                           gpointer lines[],
                           gint width);

Perform resampling of width chroma pixels in lines .

Parameters

resample	a GstVideoChromaResample
lines	pixel lines
width	the number of pixels on one line

gst_video_chroma_resample_free ()

void
gst_video_chroma_resample_free (GstVideoChromaResample *resample);

Free resample

Parameters

resample

a GstVideoChromaResample

gst_video_chroma_resample_get_info ()

void
gst_video_chroma_resample_get_info (GstVideoChromaResample *resample,
                                    guint *n_lines,
                                    gint *offset);

The resampler must be fed n_lines at a time. The first line should be at offset .

Parameters

resample	a GstVideoChromaResample
n_lines	the number of input lines
offset	the first line

gst_video_chroma_resample_new ()

GstVideoChromaResample *
gst_video_chroma_resample_new (GstVideoChromaMethod method,
                               GstVideoChromaSite site,
                               GstVideoChromaFlags flags,
                               GstVideoFormat format,
                               gint h_factor,
                               gint v_factor);

Create a new resampler object for the given parameters. When h_factor or v_factor is > 0, upsampling will be used, otherwise subsampling is performed.

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Parameters

method	a GstVideoChromaMethod
site	a GstVideoChromaSite
flags	GstVideoChromaFlags
format	the GstVideoFormat
h_factor	horizontal resampling factor
v_factor	vertical resampling factor

Returns

a new GstVideoChromaResample that should be freed with gst_video_chroma_resample_free() after usage.

Types and Values

enum GstVideoChromaSite

Various Chroma sitings.

Members

GST_VIDEO_CHROMA_SITE_UNKNOWN	unknown cositing
GST_VIDEO_CHROMA_SITE_NONE	no cositing
GST_VIDEO_CHROMA_SITE_H_COSITED	chroma is horizontally cosited
GST_VIDEO_CHROMA_SITE_V_COSITED	chroma is vertically cosited
GST_VIDEO_CHROMA_SITE_ALT_LINE	choma samples are sited on alternate lines
GST_VIDEO_CHROMA_SITE_COSITED	chroma samples cosited with luma samples
GST_VIDEO_CHROMA_SITE_JPEG	jpeg style cositing, also for mpeg1 and mjpeg
GST_VIDEO_CHROMA_SITE_MPEG2	mpeg2 style cositing
GST_VIDEO_CHROMA_SITE_DV	DV style cositing

enum GstVideoChromaFlags

Extra flags that influence the result from gst_video_chroma_resample_new().

Members

GST_VIDEO_CHROMA_FLAG_NONE	no flags
GST_VIDEO_CHROMA_FLAG_INTERLACED	the input is interlaced

enum GstVideoChromaMethod

Different subsampling and upsampling methods

Members

GST_VIDEO_CHROMA_METHOD_NEAREST	Duplicates the chroma samples when upsampling and drops when subsampling
GST_VIDEO_CHROMA_METHOD_LINEAR	Uses linear interpolation to reconstruct missing chroma and averaging to subsample

GstVideoChromaResample

typedef struct _GstVideoChromaResample GstVideoChromaResample;