commit 555a06b6146d8f695a7655eb7fc17b8bb01a8af9
author Harish Mahendrakar <harish.mahendrakar@ittiam.com> Wed Dec 14 09:37:27 2022 -0800
committer Dichen Zhang <dichenzhang@google.com> Thu Jan 19 02:05:50 2023 +0000
tree b5e3fc2c34e7c5b185ddac87788dd230e6ee1f7d
parent 1107ff3272027f7a9a9924f7da9be2ecd5e616f7

jpegrecoverymap: Added LUT implementations for various OETF and InvOETF functions

Instead of computing these for each pixel, these are computed once
at 10-bit precision (index from 0 to 1023) and are used to speed up
the computations.

Bug: 261877699
Test: push files from tests/data to /sdcard/Documents and then \
 atest libjpegdecoder_test libjpegencoder_test libjpegrecoverymap_test
Change-Id: Ifd98a96a78bc38879a77d86ebab137a4efc8fa20

libs/jpegrecoverymap/recoverymap.cpp

diff --git a/libs/jpegrecoverymap/recoverymap.cpp b/libs/jpegrecoverymap/recoverymap.cpp
index 222b5f0..a898f1e 100644
--- a/libs/jpegrecoverymap/recoverymap.cpp
+++ b/libs/jpegrecoverymap/recoverymap.cpp
@@ -41,6 +41,12 @@
 
 namespace android::recoverymap {
 
+#define USE_SRGB_INVOETF_LUT 1
+#define USE_HLG_OETF_LUT 1
+#define USE_PQ_OETF_LUT 1
+#define USE_HLG_INVOETF_LUT 1
+#define USE_PQ_INVOETF_LUT 1
+
 #define JPEGR_CHECK(x)          \
   {                             \
     status_t status = (x);      \
@@ -741,11 +747,19 @@
       hdrInvOetf = identityConversion;
       break;
     case JPEGR_TF_HLG:
+#if USE_HLG_INVOETF_LUT
+      hdrInvOetf = hlgInvOetfLUT;
+#else
       hdrInvOetf = hlgInvOetf;
+#endif
       hdr_white_nits = kHlgMaxNits;
       break;
     case JPEGR_TF_PQ:
+#if USE_PQ_INVOETF_LUT
+      hdrInvOetf = pqInvOetfLUT;
+#else
       hdrInvOetf = pqInvOetf;
+#endif
       hdr_white_nits = kPqMaxNits;
       break;
     case JPEGR_TF_UNSPECIFIED:
@@ -817,7 +831,11 @@
           Color sdr_yuv_gamma =
               sampleYuv420(uncompressed_yuv_420_image, kMapDimensionScaleFactor, x, y);
           Color sdr_rgb_gamma = srgbYuvToRgb(sdr_yuv_gamma);
+#if USE_SRGB_INVOETF_LUT
+          Color sdr_rgb = srgbInvOetfLUT(sdr_rgb_gamma);
+#else
           Color sdr_rgb = srgbInvOetf(sdr_rgb_gamma);
+#endif
           float sdr_y_nits = luminanceFn(sdr_rgb) * kSdrWhiteNits;
 
           Color hdr_yuv_gamma = sampleP010(uncompressed_p010_image, kMapDimensionScaleFactor, x, y);
@@ -905,10 +923,18 @@
         hdrOetf = identityConversion;
         break;
       case JPEGR_TF_HLG:
+#if USE_HLG_OETF_LUT
+        hdrOetf = hlgOetfLUT;
+#else
         hdrOetf = hlgOetf;
+#endif
         break;
       case JPEGR_TF_PQ:
+#if USE_PQ_OETF_LUT
+        hdrOetf = pqOetfLUT;
+#else
         hdrOetf = pqOetf;
+#endif
         break;
       case JPEGR_TF_UNSPECIFIED:
         // Should be impossible to hit after input validation.
@@ -921,8 +947,11 @@
         for (size_t x = 0; x < width; ++x) {
           Color yuv_gamma_sdr = getYuv420Pixel(uncompressed_yuv_420_image, x, y);
           Color rgb_gamma_sdr = srgbYuvToRgb(yuv_gamma_sdr);
+#if USE_SRGB_INVOETF_LUT
+          Color rgb_sdr = srgbInvOetfLUT(rgb_gamma_sdr);
+#else
           Color rgb_sdr = srgbInvOetf(rgb_gamma_sdr);
-
+#endif
           float recovery;
           // TODO: determine map scaling factor based on actual map dims
           size_t map_scale_factor = kMapDimensionScaleFactor;