dnr

dnr — Dynamic noise reduction

Properties

guint chroma-lock Read / Write
guint chroma-threshold Read / Write
guint luma-lock Read / Write
guint luma-threshold Read / Write
guint scene-change Read / Write

Types and Values

typedef GstEntransDnr

Object Hierarchy

    GObject
    ╰── GInitiallyUnowned
        ╰── GstObject
            ╰── GstElement
                ╰── GstBaseTransform
                    ╰── GstVideoFilter
                        ╰── GstEntransDnr

Description

Operation

[translated from German transcode documentation]

The filter operates best on material in YUV/I420 format, but can also be used for RGB material.

It operates only on one image when no scene-change is recognized. This is determined by the proportion of pixels in an image that have exceeded all threshold values (so when this propertion exceeds the prescribed scene-change value).

The filter examines each pixel of a picture separately according to luma and chroma portions (YUV mode) and/or R/G/B portions (RGB mode), so that both brightness and color noise can be treated separately.

The threshold values luma-threshold and chroma-threshold indicate to what extent of difference between a pixel of the previous image and one of the current image a "cross fade" of pixels is applied. The former is used on the luma (or R) component, the latter on chroma (or G/B) components.

The threshold values luma-lock and chroma-lock indicate to what extent of difference between a pixel of the previous image and one of the current image a "replacement" by a previous pixel is performed, that is, whether the pixel value is kept locked. The former is used on the luma (or R) component, the latter on chroma (or G/B) components. In any event, a pixel will be "refreshed" after at most 30 locks.

In principle the threshold values should be larger than the lock values, so that a balanced relationship between "locking" and "cross-fading" ensues. The threshold values are compared with the differences (biased) of pixels, i.e. larger threshold values strengthen the filter effect, because also larger differences (differences) are thus filtered. The default parameter values should yield a usable result in most cases. The filter has (then) altogether beside that noise reduction a soft-drawing effect however without "streak-effect" with movement. After filtering noise-afflicted material, (e.g. MPEG) compression can save up to 25% bitrate (this can however clearly be more or less depending on material).

History

  • transcode dnr filter [Gerhard Monzel]
  • Also available in avidemux (Denoise)


Element Information

plugin

transcode

author

Mark Nauwelaerts <mnauw@users.sourceforge.net>, Gerhard Monzel

class

Filter/Effect/Video

Functions

Types and Values

GstEntransDnr

typedef GstDnr GstEntransDnr;

Property Details

The “chroma-lock” property

  “chroma-lock”              guint

Threshold to lock chroma/green+blue.

Flags: Read / Write

Allowed values: [1,128]

Default value: 8


The “chroma-threshold” property

  “chroma-threshold”         guint

Threshold to blend chroma/green+blue.

Flags: Read / Write

Allowed values: [1,128]

Default value: 16


The “luma-lock” property

  “luma-lock”                guint

Threshold to lock luma/red.

Flags: Read / Write

Allowed values: [1,128]

Default value: 4


The “luma-threshold” property

  “luma-threshold”           guint

Threshold to blend luma/red.

Flags: Read / Write

Allowed values: [1,128]

Default value: 10


The “scene-change” property

  “scene-change”             guint

Percentage of picture difference (scene change).

Flags: Read / Write

Allowed values: [1,90]

Default value: 30