Resolve clang-tidy lints in VideoEncoder (#897)

Co-authored-by: Daniel Flores <[email protected]>

Author: Dan-Flores

src/torchcodec/_core/Encoder.cpp

@@ -598,8 +598,8 @@ void VideoEncoder::initializeEncoder(
   // TODO-VideoEncoder: Remove assumption that tensor in NCHW format
   auto sizes = frames_.sizes();
   inPixelFormat_ = AV_PIX_FMT_GBRP;
-  inHeight_ = sizes[2];
-  inWidth_ = sizes[3];
+  inHeight_ = static_cast<int>(sizes[2]);
+  inWidth_ = static_cast<int>(sizes[3]);
 
   // Use specified dimensions or input dimensions
   // TODO-VideoEncoder: Allow height and width to be set
@@ -664,7 +664,7 @@ void VideoEncoder::encode() {
       getFFMPEGErrorStringFromErrorCode(status));
 
   AutoAVPacket autoAVPacket;
-  int numFrames = frames_.sizes()[0];
+  int numFrames = static_cast<int>(frames_.sizes()[0]);
   for (int i = 0; i < numFrames; ++i) {
     torch::Tensor currFrame = frames_[i];
     UniqueAVFrame avFrame = convertTensorToAVFrame(currFrame, i);

src/torchcodec/_core/Encoder.h

@@ -125,6 +125,16 @@ class VideoEncoder {
  public:
   ~VideoEncoder();
 
+  // Rule of Five requires that we define copy and move
+  // constructors and assignment operators.
+  // Both are deleted because we have unique_ptr members
+  VideoEncoder(const VideoEncoder&) = delete;
+  VideoEncoder& operator=(const VideoEncoder&) = delete;
+
+  // Move assignment operator deleted since we have a const member
+  VideoEncoder(VideoEncoder&&) = default;
+  VideoEncoder& operator=(VideoEncoder&&) = delete;
+
   VideoEncoder(
       const torch::Tensor& frames,
       int frameRate,
@@ -143,7 +153,7 @@ class VideoEncoder {
 
   UniqueEncodingAVFormatContext avFormatContext_;
   UniqueAVCodecContext avCodecContext_;
-  int streamIndex_;
+  int streamIndex_ = -1;
   UniqueSwsContext swsContext_;
 
   const torch::Tensor frames_;