Systems, methods, and instrumentalities are disclosed for performing stepwise scaling conversion to piecewise linear for film grain synthesis. The device may obtain a first set of film grain scaling factors. Each of the first set of film grain scaling factors may be associated with an intensity interval. The first set of film grain scaling factors may be represented by a stepwise function. The device may generate a second set of film grain scaling factors from the first set of film grain scaling factors. The second set of film grain scaling factors may be represented by a piecewise linear function or a lookup table (LUT).

In some embodiments, a method receives a first image and a second image for a comparison of film grain. The first image or the second image is analyzed to determine a first texture representation of the first image or a second texture representation of the second image. A set of regions is analyzed based on the first texture representation or the second texture representation. The method converts the set of regions from a spatial domain to a frequency domain to generate a first frequency domain representation for the set of regions in the first image and a second frequency domain representation for the set of regions in the second image. A score is generated for an assessment of differences of the film grain in the first image and the second image based on the first frequency domain representation and the second frequency domain representation.

Example devices and techniques are described. An example device includes one or more memories configured to store video data and one or more processors configured to receive, in a bitstream, one or more first messages each specifying at least one respective film grain characteristic applicable to first video data of the video data and each corresponding to a different film grain synthesis technique. The one or more processors are configured to determine that a first film grain synthesis technique specified by a first message of the one or more first messages corresponds to a device supported film grain synthesis technique. The one or more processors are configured to apply, based on a determination that the first film grain synthesis technique corresponds to a device supported film grain synthesis technique, the device supported film grain synthesis technique to the first video data based on contents of the first message.

In some embodiments, source content is received. A method decomposes the source content into a plurality of components. The components in the plurality of components include first film grain content and second film grain content. The first film grain content is processed where the first film grain content is processed via an encoder system or a film grain synthesis system. The method delivers information for the first film grain content that was processed via the encoder system or the film grain synthesis system to a client device. The second film grain content is not delivered to the client device.

A device includes a memory configured to store film grain information. The device also includes one or more processors coupled to the memory and configured to downscale a first image frame having a first resolution to obtain a second image frame having a second resolution. The one or more processors are also configured to obtain, based on the film grain information, film grain data associated with the second resolution. The one or more processors are configured to output an output image frame based on the second image frame and the film grain data.