gpujpeg_parameters_chroma_subsampling: allow setting to 0

Setting the value to GPUJPEG_SUBSAMPLING_UNKNOWN (== 0) may be useful
eg. if user sets subsampling explicitly but want to revert to implicit
setting for the encoder later.

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.8.0 FATAL_ERROR)
 # change version also in configure.ac
-project(gpujpeg VERSION 0.25.1 LANGUAGES C CUDA)
+project(gpujpeg VERSION 0.25.2 LANGUAGES C CUDA)
 
 # options
 set(BUILD_OPENGL OFF CACHE STRING "Build with OpenGL support, options are: AUTO ON OFF")

NEWS.md

@@ -1,3 +1,10 @@
+2024-04-09 - 0.25.2
+----------
+- allowed setting subsampling 4:0:0 for color input image
+- allowed passing GPUJPEG_SUBSAMPLING_UNKNOWN to
+  gpujpeg_parameters_chroma_subsampling() to disable explicitly set
+  subsampling and return to implicit (automatic) one on the encoder
+
 2024-04-05 - 0.25.1
 ----------
 - added gpujpeg_default[_image]_parameters() functions returning the

configure.ac

@@ -1,6 +1,6 @@
 AC_PREREQ([2.65])
 # change version also in CMakeLists.txt
-AC_INIT([libgpujpeg],[0.25.1],[https://github.com/CESNET/GPUJPEG/issues],[libgpujpeg],[https://github.com/CESNET/GPUJPEG])
+AC_INIT([libgpujpeg],[0.25.2],[https://github.com/CESNET/GPUJPEG/issues],[libgpujpeg],[https://github.com/CESNET/GPUJPEG])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR([src/main.c])
 AC_CONFIG_AUX_DIR([.])

src/gpujpeg_common.c

@@ -300,7 +300,7 @@ gpujpeg_parameters_chroma_subsampling(struct gpujpeg_parameters* param,
         }
         param->comp_count += 1;
     }
-    GPUJPEG_ASSERT(param->comp_count >= 1 && "Invalid subsampling!");
+    GPUJPEG_ASSERT((subsampling == GPUJPEG_SUBSAMPLING_UNKNOWN || param->comp_count >= 1) && "Invalid subsampling!");
     for ( ; comp < GPUJPEG_MAX_COMPONENT_COUNT; ++comp ) {
         param->sampling_factor[comp].horizontal = 0;
         param->sampling_factor[comp].vertical = 0;