From bce5d364df92f99df45f2467a7a818d40b7c6f7f Mon Sep 17 00:00:00 2001
From: Vadim Levin <vadim.levin@xperience.ai>
Date: Thu, 27 Aug 2020 15:11:45 +0300
Subject: [PATCH] feat: change OpenJPEG encoder to lossy with default
 parameters

---
 modules/imgcodecs/src/grfmt_jpeg2000_openjpeg.cpp |  6 ++++++
 modules/imgcodecs/test/test_read_write.cpp        | 10 ++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/modules/imgcodecs/src/grfmt_jpeg2000_openjpeg.cpp b/modules/imgcodecs/src/grfmt_jpeg2000_openjpeg.cpp
index 4771559439..0f1629302a 100644
--- a/modules/imgcodecs/src/grfmt_jpeg2000_openjpeg.cpp
+++ b/modules/imgcodecs/src/grfmt_jpeg2000_openjpeg.cpp
@@ -327,12 +327,14 @@ opj_cparameters setupEncoderParameters(const std::vector<int>& params)
 {
     opj_cparameters parameters;
     opj_set_default_encoder_parameters(&parameters);
+    bool rate_is_specified = false;
     for (size_t i = 0; i < params.size(); i += 2)
     {
         switch (params[i])
         {
         case cv::IMWRITE_JPEG2000_COMPRESSION_X1000:
             parameters.tcp_rates[0] = 1000.f / std::min(std::max(params[i + 1], 1), 1000);
+            rate_is_specified = true;
             break;
         default:
             CV_LOG_WARNING(NULL, "OpenJPEG2000(encoder): skip unsupported parameter: " << params[i]);
@@ -341,6 +343,10 @@ opj_cparameters setupEncoderParameters(const std::vector<int>& params)
     }
     parameters.tcp_numlayers = 1;
     parameters.cp_disto_alloc = 1;
+    if (!rate_is_specified)
+    {
+        parameters.tcp_rates[0] = 4;
+    }
     return parameters;
 }
 
diff --git a/modules/imgcodecs/test/test_read_write.cpp b/modules/imgcodecs/test/test_read_write.cpp
index 890d47a543..9dbd2e33c7 100644
--- a/modules/imgcodecs/test/test_read_write.cpp
+++ b/modules/imgcodecs/test/test_read_write.cpp
@@ -228,9 +228,12 @@ TEST_P(Imgcodecs_Image, read_write_BGR)
     double psnrThreshold = 100;
     if (ext == "jpg")
         psnrThreshold = 32;
-#ifdef HAVE_JASPER
+#if defined(HAVE_JASPER)
     if (ext == "jp2")
         psnrThreshold = 95;
+#elif defined(HAVE_OPENJPEG)
+    if (ext == "jp2")
+        psnrThreshold = 35;
 #endif
 
     Mat image = generateTestImageBGR();
@@ -254,9 +257,12 @@ TEST_P(Imgcodecs_Image, read_write_GRAYSCALE)
     double psnrThreshold = 100;
     if (ext == "jpg")
         psnrThreshold = 40;
-#ifdef HAVE_JASPER
+#if defined(HAVE_JASPER)
     if (ext == "jp2")
         psnrThreshold = 70;
+#elif defined(HAVE_OPENJPEG)
+    if (ext == "jp2")
+        psnrThreshold = 35;
 #endif
 
     Mat image = generateTestImageGrayscale();