refactor ffmpegcommon

Author: Molly Xu

src/torchcodec/_core/CudaDeviceInterface.cpp

@@ -62,7 +62,7 @@ UniqueAVBufferRef getHardwareDeviceContext(const torch::Device& device) {
   AVBufferRef* hw_device_ctx_raw = nullptr;
   std::string deviceOrdinal = std::to_string(nonNegativeDeviceIndex);
 
-  int flags = getHardwareDeviceCreationFlags();
+  int flags = (canReuseHardwareContext()) ? AV_CUDA_USE_CURRENT_CONTEXT : 0;
   int err = av_hwdevice_ctx_create(
       &hw_device_ctx_raw, type, deviceOrdinal.c_str(), nullptr, flags);
 

src/torchcodec/_core/FFMPEGCommon.cpp

@@ -585,11 +585,11 @@ int64_t computeSafeDuration(
   }
 }
 
-int64_t getHardwareDeviceCreationFlags() {
+int64_t canReuseHardwareContext() {
   // 58.26.100 introduced the concept of reusing the existing cuda context
   // which is much faster and lower memory than creating a new cuda context.
 #if LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(58, 26, 100)
-  return AV_CUDA_USE_CURRENT_CONTEXT;
+  return 1;
 #else
   return 0;
 #endif

src/torchcodec/_core/FFMPEGCommon.h

@@ -22,8 +22,6 @@ extern "C" {
 #include <libavutil/dict.h>
 #include <libavutil/display.h>
 #include <libavutil/file.h>
-#include <libavutil/hwcontext.h>
-#include <libavutil/hwcontext_cuda.h>
 #include <libavutil/opt.h>
 #include <libavutil/pixfmt.h>
 #include <libavutil/version.h>
@@ -243,9 +241,8 @@ AVFilterContext* createBuffersinkFilter(
     AVFilterGraph* filterGraph,
     enum AVPixelFormat outputFormat);
 
-// Returns the appropriate flags for av_hwdevice_ctx_create() based on FFmpeg
-// version. This abstracts FFmpeg version differences for hardware device
-// context creation.
-int64_t getHardwareDeviceCreationFlags();
+// Returns whether hardware context can be reused based on FFmpeg
+// version.
+int64_t canReuseHardwareContext();
 
 } // namespace facebook::torchcodec