Use std::move to reduce copies in VideoEncoder (#1056)

Author: Dan-Flores

src/torchcodec/_core/Encoder.cpp

@@ -607,7 +607,7 @@ void tryToValidateCodecOption(
           "] for this codec. For more details, run 'ffmpeg -h encoder=",
           avCodec.name,
           "'");
-    } catch (const std::invalid_argument& e) {
+    } catch (const std::invalid_argument&) {
       TORCH_CHECK(
           false,
           "Option ",

src/torchcodec/_core/custom_ops.cpp

@@ -613,14 +613,14 @@ void encode_video_to_file(
     const at::Tensor& frames,
     int64_t frame_rate,
     std::string_view file_name,
-    std::optional<std::string> codec = std::nullopt,
+    std::optional<std::string_view> codec = std::nullopt,
     std::optional<std::string_view> pixel_format = std::nullopt,
     std::optional<double> crf = std::nullopt,
     std::optional<std::string_view> preset = std::nullopt,
     std::optional<std::vector<std::string>> extra_options = std::nullopt) {
   VideoStreamOptions videoStreamOptions;
-  videoStreamOptions.codec = codec;
-  videoStreamOptions.pixelFormat = pixel_format;
+  videoStreamOptions.codec = std::move(codec);
+  videoStreamOptions.pixelFormat = std::move(pixel_format);
   videoStreamOptions.crf = crf;
   videoStreamOptions.preset = preset;
 
@@ -641,15 +641,15 @@ at::Tensor encode_video_to_tensor(
     const at::Tensor& frames,
     int64_t frame_rate,
     std::string_view format,
-    std::optional<std::string> codec = std::nullopt,
+    std::optional<std::string_view> codec = std::nullopt,
     std::optional<std::string_view> pixel_format = std::nullopt,
     std::optional<double> crf = std::nullopt,
     std::optional<std::string_view> preset = std::nullopt,
     std::optional<std::vector<std::string>> extra_options = std::nullopt) {
   auto avioContextHolder = std::make_unique<AVIOToTensorContext>();
   VideoStreamOptions videoStreamOptions;
-  videoStreamOptions.codec = codec;
-  videoStreamOptions.pixelFormat = pixel_format;
+  videoStreamOptions.codec = std::move(codec);
+  videoStreamOptions.pixelFormat = std::move(pixel_format);
   videoStreamOptions.crf = crf;
   videoStreamOptions.preset = preset;
 
@@ -672,7 +672,7 @@ void _encode_video_to_file_like(
     int64_t frame_rate,
     std::string_view format,
     int64_t file_like_context,
-    std::optional<std::string> codec = std::nullopt,
+    std::optional<std::string_view> codec = std::nullopt,
     std::optional<std::string_view> pixel_format = std::nullopt,
     std::optional<double> crf = std::nullopt,
     std::optional<std::string_view> preset = std::nullopt,
@@ -684,8 +684,8 @@ void _encode_video_to_file_like(
   std::unique_ptr<AVIOFileLikeContext> avioContextHolder(fileLikeContext);
 
   VideoStreamOptions videoStreamOptions;
-  videoStreamOptions.codec = codec;
-  videoStreamOptions.pixelFormat = pixel_format;
+  videoStreamOptions.codec = std::move(codec);
+  videoStreamOptions.pixelFormat = std::move(pixel_format);
   videoStreamOptions.crf = crf;
   videoStreamOptions.preset = preset;
 

src/torchcodec/_core/ops.py

@@ -331,7 +331,7 @@ def encode_video_to_file_abstract(
     frames: torch.Tensor,
     frame_rate: int,
     filename: str,
-    codec: Optional[str],
+    codec: Optional[str] = None,
     pixel_format: Optional[str] = None,
     preset: Optional[str] = None,
     crf: Optional[Union[int, float]] = None,
@@ -345,7 +345,7 @@ def encode_video_to_tensor_abstract(
     frames: torch.Tensor,
     frame_rate: int,
     format: str,
-    codec: Optional[str],
+    codec: Optional[str] = None,
     pixel_format: Optional[str] = None,
     preset: Optional[str] = None,
     crf: Optional[Union[int, float]] = None,
@@ -360,7 +360,7 @@ def _encode_video_to_file_like_abstract(
     frame_rate: int,
     format: str,
     file_like_context: int,
-    codec: Optional[str],
+    codec: Optional[str] = None,
     pixel_format: Optional[str] = None,
     preset: Optional[str] = None,
     crf: Optional[Union[int, float]] = None,

src/torchcodec/encoders/_video_encoder.py

@@ -35,12 +35,12 @@ def __init__(self, frames: Tensor, *, frame_rate: int):
     def to_file(
         self,
         dest: Union[str, Path],
-        extra_options: Optional[Dict[str, Any]] = None,
         *,
         codec: Optional[str] = None,
         pixel_format: Optional[str] = None,
         crf: Optional[Union[int, float]] = None,
         preset: Optional[Union[str, int]] = None,
+        extra_options: Optional[Dict[str, Any]] = None,
     ) -> None:
         """Encode frames into a file.