Enable multi-threaded jxl decompression

Summary: There are helper methods to makde jxl decompression multi-threaded, just use them.

Reviewed By: kiminoue7

Differential Revision: D51542155

fbshipit-source-id: b66bb3ee95bfad0c70d422f5d26f8b973b3b4db4

vrs/utils/PixelFrame.cpp

@@ -31,7 +31,7 @@ using namespace std;
 
 namespace {
 
-static const uint8_t kNaNPixel = 0;
+const uint8_t kNaNPixel = 0;
 
 /// normalize floating point pixels to grey8
 template <class Float>

vrs/utils/PixelFrameJxl.cpp

@@ -27,6 +27,7 @@
 #include <jxl/decode_cxx.h>
 #include <jxl/encode.h>
 #include <jxl/encode_cxx.h>
+#include <jxl/thread_parallel_runner_cxx.h>
 #include <jxl/types.h>
 #endif
 
@@ -140,10 +141,16 @@ bool PixelFrame::readJxlFrame(RecordReader* reader, const uint32_t sizeBytes) {
 
 bool PixelFrame::readJxlFrame(const vector<uint8_t>& jxlBuf, bool decodePixels) {
 #ifdef JXL_IS_AVAILABLE
-  auto dec = getThreadJxlDecoder();
+  JxlDecoder* dec = getThreadJxlDecoder();
   if (!XR_VERIFY(dec != nullptr)) {
     return false;
   }
+
+  size_t hw_threads = JxlThreadParallelRunnerDefaultNumWorkerThreads();
+  JxlThreadParallelRunnerPtr runner_fixed =
+      JxlThreadParallelRunnerMake(nullptr, std::min<size_t>(hw_threads, 4));
+  DEC_CHECK(JxlDecoderSetParallelRunner(dec, JxlThreadParallelRunner, runner_fixed.get()));
+
   DEC_CHECK(JxlDecoderSubscribeEvents(
       dec, JXL_DEC_BASIC_INFO | JXL_DEC_COLOR_ENCODING | JXL_DEC_FULL_IMAGE));
 
@@ -338,7 +345,7 @@ bool PixelFrame::jxlCompress(
   }
   ENC_CHECK(JxlEncoderSetColorEncoding(enc, &color_encoding));
 
-  auto settings = JxlEncoderFrameSettingsCreate(enc, nullptr);
+  JxlEncoderFrameSettings* settings = JxlEncoderFrameSettingsCreate(enc, nullptr);
   ENC_CHECK(JxlEncoderFrameSettingsSetOption(settings, JXL_ENC_FRAME_SETTING_EFFORT, effort));
   ENC_CHECK(JxlEncoderFrameSettingsSetOption(
       settings, JXL_ENC_FRAME_SETTING_DECODING_SPEED, decoding_speed_tier));