Dynamic range converter with frame by frame adaptation and methods for use therewith

Patent metadata

Field	Value
Publication number	US-2016205371-A1
Application number	US-201514873916-A
Country	US
Kind code	A1
Filing date	Oct 2, 2015
Priority date	Jan 9, 2015
Publication date	Jul 14, 2016
Grant date	—

Abstract

In various embodiments, a dynamic range converter includes a first color space converter to convert a source color space of a source video having a source dynamic range to nonlinear color space signals. A linearizer configured converts the nonlinear color space signals to linearized color space signals having a mastering dynamic range via a piecewise linear interpolation of a transfer function. A color volume transformer applies dynamic color transform metadata associated with the source video on a frame by frame basis to generate master adjusted color space signals from the linearized color space signals. A delinearizer converts the master adjusted color space signals to nonlinearized color space signals via a piecewise linear interpolation of an inverse transfer function in accordance with a display dynamic range. A second color space converter converts the nonlinearized color space signals to display domain signals. Other embodiments are disclosed.

First claim

What is claimed is:

1 . A dynamic range converter comprising:
a first color space converter configured to convert a source color space of a source video having a source dynamic range to nonlinear color space signals; a linearizer configured to convert the nonlinear color space signals to linearized color space signals having a mastering dynamic range via a piecewise linear interpolation of a transfer function; a color volume transformer configured to apply dynamic color transform metadata associated with the source video on a frame by frame basis to generate master adjusted color space signals from the linearized color space signals; a delinearizer configured to convert the master adjusted color space signals to nonlinearized color space signals via a piecewise linear interpolation of an inverse transfer function in accordance with a display dynamic range; and a second color space converter configured to convert the nonlinearized color space signals to display domain signals.

2 . The dynamic range converter of claim 1 wherein the color volume transformer:
loads a plurality of first registers, prior to a first time period, with the dynamic color transform metadata associated with a first video frame of the source video;
processes first frame data corresponding to the first video frame of the source video during the first time period using the dynamic color transform metadata associated with the first video frame of the source video loaded in the plurality of first registers; and
loads a plurality of second registers, during the first time period, with the dynamic color transform metadata associated with a second video frame of the source video.

3 . The dynamic range converter of claim 2 wherein the color volume transformer:
processes second frame data corresponding to the second video frame of the source video during a second time period that is after the first time period, using the dynamic color transform metadata associated with the second video frame of the source video loaded in the plurality of second registers; and
loads the plurality of first registers, during the second time period, with the dynamic color transform metadata associated with a third video frame of the source video.

4 . The dynamic range converter of claim 3 wherein the color volume transformer switches from processing of video data corresponding to the first video frame of the source video to processing of video data corresponding to the second video frame of the source video in response to frame boundary.

5 . The dynamic range converter of claim 4 wherein the color volume transformer includes a plurality of circuits that operate in a pipelined configuration under control of a pixel clock, and wherein the frame boundary is determined based on processing of the last pixel of the first video frame.

6 . The dynamic range converter of claim 5 wherein the plurality of circuits of the color volume transformer switch from processing of the video data corresponding to the first video frame of the source video to processing of the video data corresponding to the second video frame of the source video in response to the frame boundary, at staggered times in accordance with the pipelined configuration.

7 . The dynamic range converter of claim 6 wherein the color volume transformer includes:
a third color space converter configured to that apply gamut shaping to the linearized color space signals in accordance with the dynamic color transform metadata to generate gamut shaped components;
a first tone mapper configured to apply first tone mapping by scaling the gamut shaped components in accordance with the dynamic color transform metadata to generate first mapped components;
a fourth color space converter configured to color converts the first mapped components in accordance with the dynamic color transform metadata to generate color remapped components;
a second tone mapper configured to apply second tone mapping by scaling the color remapped components in accordance with the dynamic color transform metadata to generate second mapped components; and
a fifth color space converter configured to color converts the second mapped components in accordance with the dynamic color transform metadata to generate the master adjusted color space signals.

8 . The dynamic range converter of claim 7 wherein the first tone mapper operates in accordance with the dynamic color transform metadata to:
generate a weighted maximum of the gamut shaped components;
index the weighted maximum to a piecewise linear lookup table to obtain a scale factor for each of the gamut shaped components; and
multiply the scale factor by a corresponding one of the gamut shaped components to generate the first mapped components.

9 . The dynamic range converter of claim 7 wherein the second tone mapper operates in accordance with the dynamic color transform metadata to:
generate a weighted maximum of the color remapped components;
index the weighted maximum to a piecewise linear lookup table to obtain a scale factor for each of the color remapped components; and
multiply the scale factor by a corresponding one of the color remapped components to generate the second mapped components.

10 . The dynamic range converter of claim 1 wherein the linearizer and nonlinearizer are responsive to first configuration data to selectively operate in a first mode of operation where the source dynamic range is a high dynamic range and the display dynamic range is a standard dynamic range are further responsive to second configuration data to selectively operate in a second mode of operation where the source dynamic range is a standard dynamic range and the display dynamic range is a high dynamic range.

11 . The dynamic range converter of claim 1 wherein the transfer function is one of: a electro-optical transfer function or a gamma function, and the inverse transfer function is a corresponding one of: an inverse of the electro-optical transfer function or an inverse of the gamma function.

12 . A method comprising:
converting a source color space of a source video having a source dynamic range to nonlinear color space signals; converting the nonlinear color space signals to linearized color space signals having a mastering dynamic range via a piecewise linear interpolation of a transfer function; color volume transforming the linearized color space signals on a frame by frame basis, based on dynamic color transform metadata associated with the source video, to generate master adjusted color space signals; delinearizing the master adjusted color space signals to nonlinearized color space signals via a piecewise linear interpolation of an inverse transfer function in accordance with a display dynamic range; and converting the nonlinearized color space signals to display domain signals.

13 . The method of claim 12 wherein the color volume transforming includes:
loading in a plurality of first registers prior to a first time period, the dynamic color transform metadata associated with a first video frame of the source video;
processing first frame data corresponding to the first video frame of the source video during the first time period using the dynamic color transform metadata associated with the first video frame of the source video loaded in the plurality of first registers;
loading in a plurality of second registers during the first time period, the dynamic color transform metadata associated with a second video frame of the source video;
processing second frame data corresponding to the second video frame of the source video during a second time period that is after the first time

Assignees

• Vixs Systems Inc

Inventors

• Wallace Bradley Arthur
• Wu Xiaowen

Classifications

• H04N9/68

  for controlling the amplitude of colour signals, e.g. automatic chroma control circuits (H04N9/71, H04N9/73 take precedence; camera processing pipelines for controlling the colour saturation of colour signals H04N23/86) · CPC title

• H04N9/67

  for matrixing (camera processing pipelines for matrixing of colour signals H04N23/85) · CPC title

• H04N9/64 Primary

  Circuits for processing colour signals (H04N9/77 takes precedence; camera processing pipelines for processing colour signals H04N23/84) · CPC title

• H04N5/20 Primary

  Circuitry for controlling amplitude response · CPC title

• G06T1/20

  Processor architectures; Processor configuration, e.g. pipelining · CPC title