[torchcodec] stream_index should not be optional for getting frame by…

… index

Differential Revision: D58505608

src/torchcodec/decoders/_core/VideoDecoderOps.cpp

@@ -37,9 +37,9 @@ TORCH_LIBRARY(torchcodec_ns, m) {
   m.def("get_next_frame(Tensor(a!) decoder) -> Tensor");
   m.def("get_frame_at_pts(Tensor(a!) decoder, float seconds) -> Tensor");
   m.def(
-      "get_frame_at_index(Tensor(a!) decoder, *, int frame_index, int? stream_index=None) -> Tensor");
+      "get_frame_at_index(Tensor(a!) decoder, *, int frame_index, int stream_index) -> Tensor");
   m.def(
-      "get_frames_at_indices(Tensor(a!) decoder, *, int[] frame_indices, int? stream_index=None) -> Tensor");
+      "get_frames_at_indices(Tensor(a!) decoder, *, int[] frame_indices, int stream_index) -> Tensor");
   m.def("get_json_metadata(Tensor(a!) decoder) -> str");
 }
 
@@ -131,22 +131,20 @@ at::Tensor get_frame_at_pts(at::Tensor& decoder, double seconds) {
 at::Tensor get_frame_at_index(
     at::Tensor& decoder,
     int64_t frame_index,
-    std::optional<int64_t> stream_index) {
+    int64_t stream_index) {
   auto videoDecoder = static_cast<VideoDecoder*>(decoder.mutable_data_ptr());
-  auto result =
-      videoDecoder->getFrameAtIndex(stream_index.value_or(-1), frame_index);
+  auto result = videoDecoder->getFrameAtIndex(stream_index, frame_index);
   return result.frame;
 }
 
 at::Tensor get_frames_at_indices(
     at::Tensor& decoder,
     at::IntArrayRef frame_indices,
-    std::optional<int64_t> stream_index) {
+    int64_t stream_index) {
   auto videoDecoder = static_cast<VideoDecoder*>(decoder.mutable_data_ptr());
   std::vector<int64_t> frameIndicesVec(
       frame_indices.begin(), frame_indices.end());
-  auto result = videoDecoder->getFramesAtIndexes(
-      stream_index.value_or(-1), frameIndicesVec);
+  auto result = videoDecoder->getFramesAtIndexes(stream_index, frameIndicesVec);
   return result.frames;
 }