clean up unused param

Author: Dan-Flores

src/torchcodec/_core/CudaDeviceInterface.cpp

@@ -362,7 +362,9 @@ std::string CudaDeviceInterface::getDetails() {
       (usingCPUFallback_ ? "CPU fallback." : "NVDEC.");
 }
 
-// Below are methods for video encoding:
+// --------------------------------------------------------------------------
+// Below are methods exclusive to video encoding:
+// --------------------------------------------------------------------------
 namespace {
 // RGB to NV12 color conversion matrix for BT.601 limited range.
 // NPP ColorTwist function used below expects the limited range
@@ -378,7 +380,6 @@ const Npp32f defaultLimitedRangeRgbToNv12[3][4] = {
 
 std::optional<UniqueAVFrame> CudaDeviceInterface::convertTensorToAVFrame(
     const torch::Tensor& tensor,
-    [[maybe_unused]] AVPixelFormat targetFormat,
     int frameIndex,
     AVCodecContext* codecContext) {
   TORCH_CHECK(
@@ -447,6 +448,9 @@ std::optional<UniqueAVFrame> CudaDeviceInterface::convertTensorToAVFrame(
   return avFrame;
 }
 
+// Allocates and initializes AVHWFramesContext, and sets pixel format fields
+// to enable encoding with CUDA device. The hw_frames_ctx field is needed by
+// FFmpeg to allocate frames on GPU's memory.
 void CudaDeviceInterface::setupHardwareFrameContext(
     AVCodecContext* codecContext) {
   TORCH_CHECK(codecContext != nullptr, "codecContext is null");
@@ -458,10 +462,10 @@ void CudaDeviceInterface::setupHardwareFrameContext(
       hwFramesCtxRef != nullptr,
       "Failed to allocate hardware frames context for codec");
 
-  // Always set pixel formats to options that support CUDA encoding.
-  // TODO-VideoEncoder: Enable user set pixel formats to be set and properly
-  // handled with NPP functions below
+  // TODO-VideoEncoder: Enable user set pixel formats to be set
+  // (outPixelFormat_) and handled with the appropriate NPP function
   codecContext->sw_pix_fmt = AV_PIX_FMT_NV12;
+  // Always set pixel format to support CUDA encoding.
   codecContext->pix_fmt = AV_PIX_FMT_CUDA;
 
   AVHWFramesContext* hwFramesCtx =
@@ -479,7 +483,6 @@ void CudaDeviceInterface::setupHardwareFrameContext(
         "Failed to initialize CUDA frames context for codec: ",
         getFFMPEGErrorStringFromErrorCode(ret));
   }
-
   codecContext->hw_frames_ctx = hwFramesCtxRef;
 }
 

src/torchcodec/_core/CudaDeviceInterface.h

@@ -43,7 +43,6 @@ class CudaDeviceInterface : public DeviceInterface {
 
   std::optional<UniqueAVFrame> convertTensorToAVFrame(
       const torch::Tensor& tensor,
-      AVPixelFormat targetFormat,
       int frameIndex,
       AVCodecContext* codecContext) override;
 

src/torchcodec/_core/DeviceInterface.h

@@ -141,7 +141,6 @@ class DeviceInterface {
   // Function used for video encoding, only implemented in CudaDeviceInterface.
   virtual std::optional<UniqueAVFrame> convertTensorToAVFrame(
       [[maybe_unused]] const torch::Tensor& tensor,
-      [[maybe_unused]] AVPixelFormat targetFormat,
       [[maybe_unused]] int frameIndex,
       [[maybe_unused]] AVCodecContext* codecContext) {
     return std::nullopt;

src/torchcodec/_core/Encoder.cpp

@@ -827,7 +827,8 @@ void VideoEncoder::initializeEncoder(
         0);
   }
 
-  if (frames_.device().is_cuda()) {
+  // When frames are on a CUDA device, deviceInterface_ will be defined.
+  if (frames_.device().is_cuda() && deviceInterface_) {
     deviceInterface_->registerHardwareDeviceWithCodec(avCodecContext_.get());
     deviceInterface_->setupHardwareFrameContext(avCodecContext_.get());
   }
@@ -873,9 +874,9 @@ void VideoEncoder::encode() {
   for (int i = 0; i < numFrames; ++i) {
     torch::Tensor currFrame = frames_[i];
     UniqueAVFrame avFrame;
-    if (deviceInterface_) {
+    if (frames_.device().is_cuda() && deviceInterface_) {
       auto cudaFrame = deviceInterface_->convertTensorToAVFrame(
-          currFrame, outPixelFormat_, i, avCodecContext_.get());
+          currFrame, i, avCodecContext_.get());
       TORCH_CHECK(
           cudaFrame.has_value(),
           "convertTensorToAVFrame failed for frame ",