In a method to improve backwards compatibility when decoding high-dynamic range images coded in a wide color gamut (WCG) space which may not be compatible with legacy color spaces, hue and/or saturation values of images in an image database are computed for both a legacy color space (say, YCbCr-gamma) and a preferred WCG color space (say, IPT-PQ). Based on a cost function, a reshaped color space is computed so that the distance between the hue values in the legacy color space and rotated hue values in the preferred color space is minimized HDR images are coded in the reshaped color space. Legacy devices can still decode standard dynamic range images assuming they are coded in the legacy color space, while updated devices can use color reshaping information to decode HDR images in the preferred color space at full dynamic range.

In a method to improve backwards compatibility when decoding high-dynamic range images coded in a wide color gamut (WCG) space which may not be compatible with legacy color spaces, hue and/or saturation values of images in an image database are computed for both a legacy color space (say, YCbCr-gamma) and a preferred WCG color space (say, IPT-PQ). Based on a cost function, a reshaped color space is computed so that the distance between the hue values in the legacy color space and rotated hue values in the preferred color space is minimized HDR images are coded in the reshaped color space. Legacy devices can still decode standard dynamic range images assuming they are coded in the legacy color space, while updated devices can use color reshaping information to decode HDR images in the preferred color space at full dynamic range.

Network services encode multimedia content, such as video, into multiple adaptive bitrate streams of encoded video and a separate trick play stream of encoded video to support trick play features. The trick play stream is encoded at a lower encoding bitrate and frame rate than each of the adaptive bitrate streams. The adaptive bitrate streams and the trick play stream are stored in the network services. During normal content streaming and playback, a client device downloads a selected one of the adaptive bitrate streams from network serviced for playback at the client device. To implement a trick play feature, the client device downloads the trick play stream from the network services for trick play playback.

Network services encode multimedia content, such as video, into multiple adaptive bitrate streams of encoded video and a separate trick play stream of encoded video to support trick play features. The trick play stream is encoded at a lower encoding bitrate and frame rate than each of the adaptive bitrate streams. The adaptive bitrate streams and the trick play stream are stored in the network services. During normal content streaming and playback, a client device downloads a selected one of the adaptive bitrate streams from network serviced for playback at the client device. To implement a trick play feature, the client device downloads the trick play stream from the network services for trick play playback.

For obtaining an good yet easy to use luminance dynamic range conversion, we describe an image color processing apparatus (200) arranged to transform an input color (R,G,B) of a pixel of an input image (Im_in) having a first luminance dynamic range into an output color (Rs, Gs, Bs) of a pixel of an output image (Im_res) having a second luminance dynamic range, which first and second dynamic ranges differ in extent by at least a multiplicative factor 2, comprising: a maximum determining unit (101) arranged to calculate a maximum (M) of color components of the input color, the color components at least comprising a red, green and blue component; —a uniformization unit (201) arranged to apply a function (FP) to the maximum (M) as input, which function has a logarithmic shape and was predetermined to be of a fixed shape enabling to transform a linear input to a more perceptually uniform output variable (u); a function application unit (203) arranged to receive a functional shape of a function, which was specified previously by a human color grader, and apply the function to the uniform output variable (u), yielding a transformed uniform value (TU); a linearization unit (204) arranged to transform the transformed uniform value (TU) to a linear domain value (LU); a multiplication factor determination unit (205) arranged to determine a multiplication factor (a) being equal to the linear domain value (LU) divided by the maximum (M); and a multiplier (104) arranged to multiply at least three linear color components (R,G,B) by the multiplication factor (a), yielding the output color.

For obtaining an good yet easy to use luminance dynamic range conversion, we describe an image color processing apparatus (200) arranged to transform an input color (R,G,B) of a pixel of an input image (Im_in) having a first luminance dynamic range into an output color (Rs, Gs, Bs) of a pixel of an output image (Im_res) having a second luminance dynamic range, which first and second dynamic ranges differ in extent by at least a multiplicative factor 2, comprising: a maximum determining unit (101) arranged to calculate a maximum (M) of color components of the input color, the color components at least comprising a red, green and blue component; —a uniformization unit (201) arranged to apply a function (FP) to the maximum (M) as input, which function has a logarithmic shape and was predetermined to be of a fixed shape enabling to transform a linear input to a more perceptually uniform output variable (u); a function application unit (203) arranged to receive a functional shape of a function, which was specified previously by a human color grader, and apply the function to the uniform output variable (u), yielding a transformed uniform value (TU); a linearization unit (204) arranged to transform the transformed uniform value (TU) to a linear domain value (LU); a multiplication factor determination unit (205) arranged to determine a multiplication factor (a) being equal to the linear domain value (LU) divided by the maximum (M); and a multiplier (104) arranged to multiply at least three linear color components (R,G,B) by the multiplication factor (a), yielding the output color.

The present disclosure generally relates to a method and device of encoding a color picture having color components (Ec) comprising obtaining (11) a luminance component (L) and two chrominance components (C1, C2) from the color picture to be encoded. The method for encoding a color picture having color components comprising obtaining at least one chrominance component from the color picture to be encoded, the method further comprises: —determining a first factor based on the value of each pixel (i) of said luminance component; —obtaining at least one final chrominance component by scaling said at least one chrominance component by said first factor; and—encoding (13) said at least one final chrominance component.

A method is disclosed that comprises mapping a high-dynamic range luminance picture to a standard-dynamic range luminance picture based on a backlight value Ba.sub.c associated with the high-dynamic range luminance picture.

A method is disclosed that comprises mapping a high-dynamic range luminance picture to a standard-dynamic range luminance picture based on a backlight value Ba.sub.c associated with the high-dynamic range luminance picture.

The present disclosure relates to systems and methods for transmitting Standard Dynamic Range (SDR) content. The systems and methods may use a modified Electro-Optical Transfer Function (EOTF) curve to convert nonlinear color values of SDR content into optical output values of modified SDR content. The systems and methods may encode the modified SDR content using eight bits while preventing banding. The systems and methods may transmit the encoded data to a client device for presentation on a display.