commit ebfb373efedb052eb3c10fa4429459a70ed60701
author Ram Mohan <ram.mohan@ittiam.com> Mon Aug 21 18:12:53 2023 +0530
committer Dichen Zhang <dichenzhang@google.com> Tue Aug 29 21:06:01 2023 +0000
tree b02947a572f1310032c4e7cbdca706890adef52b
parent 0202c12515ed55a4450377776d1601bbc135f4b5

ultrahdr: Correct hdr white nits for linear input

The hdr white nits for linear input is set to sdr white nits. This
causes huge losses during gain map compression. For linear inputs
now we are marking peak white nits to peak hlg white nits

Bug:
Test: ./ultrahdr_sample_app -p inp_p010.yuv -w 1920 -h 1080

Change-Id: I635d7d4cb7d2d3de9b2b24a59b175e05fbb3c189

libs/ultrahdr/jpegr.cpp

diff --git a/libs/ultrahdr/jpegr.cpp b/libs/ultrahdr/jpegr.cpp
index dc439d7..55333b3 100644
--- a/libs/ultrahdr/jpegr.cpp
+++ b/libs/ultrahdr/jpegr.cpp
@@ -817,10 +817,13 @@
   map_data.reset(reinterpret_cast<uint8_t*>(dest->data));
 
   ColorTransformFn hdrInvOetf = nullptr;
-  float hdr_white_nits = kSdrWhiteNits;
+  float hdr_white_nits;
   switch (hdr_tf) {
     case ULTRAHDR_TF_LINEAR:
       hdrInvOetf = identityConversion;
+      // Note: this will produce clipping if the input exceeds kHlgMaxNits.
+      // TODO: TF LINEAR will be deprecated.
+      hdr_white_nits = kHlgMaxNits;
       break;
     case ULTRAHDR_TF_HLG:
 #if USE_HLG_INVOETF_LUT