kiteffmpeg/io.github.yuroyami.kiteffmpeg/DolbyVisionComposition

DolbyVisionComposition

class DolbyVisionComposition : AutoCloseable

The Dolby Vision composition of one frame, which turns the base layer and its RPU into an ordinary HDR10 picture: 10-bit 4:2:0 in BT.2020 with the PQ curve, limited range, the source's range as its mastering display, and no Dolby Vision metadata left on it. Every renderer that can show HDR10 can then show it.

Start one with Frame.beginDolbyVisionComposition, fill the picture with composeRows, and take it with finish. Frame.composeDolbyVision does all three in one call on the calling thread. The composition is the reason to use this class instead: it costs tens of milliseconds for a 1080p frame on one thread, and bands of rows can run on several.

The composition holds its own reference to the source frame's buffers, so the source frame may be closed as soon as this exists.

Threading. composeRows calls may run at the same time on different threads, as long as their rows do not overlap. finish and close must wait until every composeRows call has returned.

Lifetime. Close it when you do not finish it. finish hands the picture over and closes the rest, and a later close does nothing.

Properties

height

val height: Int

The picture's height in rows, which is where the last band ends.

Functions

open override fun close()

composeRows

fun composeRows(startRow: Int, endRowExclusive: Int)

Composes rows startRow up to endRowExclusive. A band starts on an even row and ends on an even row or at height, because one row of 4:2:0 chroma serves two rows of the picture.

finish

fun finish(): Frame

The composed picture, which the caller now owns and closes. Every row must have been composed; rows that were not hold whatever the allocation left in them.