diff --git a/src/torchcodec/_core/CMakeLists.txt b/src/torchcodec/_core/CMakeLists.txt
index 1f09159e6..0793c8061 100644
--- a/src/torchcodec/_core/CMakeLists.txt
+++ b/src/torchcodec/_core/CMakeLists.txt
@@ -93,6 +93,7 @@ function(make_torchcodec_libraries
         CpuDeviceInterface.cpp
         SingleStreamDecoder.cpp
         Encoder.cpp
+        ValidationUtils.cpp
     )
 
     if(ENABLE_CUDA)
diff --git a/src/torchcodec/_core/ValidationUtils.cpp b/src/torchcodec/_core/ValidationUtils.cpp
new file mode 100644
index 000000000..fae3dd940
--- /dev/null
+++ b/src/torchcodec/_core/ValidationUtils.cpp
@@ -0,0 +1,35 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.
+// All rights reserved.
+//
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree.
+
+#include "src/torchcodec/_core/ValidationUtils.h"
+#include <limits>
+#include "c10/util/Exception.h"
+
+namespace facebook::torchcodec {
+
+int validateInt64ToInt(int64_t value, const std::string& parameterName) {
+  TORCH_CHECK(
+      value >= std::numeric_limits<int>::min() &&
+          value <= std::numeric_limits<int>::max(),
+      parameterName,
+      "=",
+      value,
+      " is out of range for int type.");
+
+  return static_cast<int>(value);
+}
+
+std::optional<int> validateOptionalInt64ToInt(
+    const std::optional<int64_t>& value,
+    const std::string& parameterName) {
+  if (value.has_value()) {
+    return validateInt64ToInt(value.value(), parameterName);
+  } else {
+    return std::nullopt;
+  }
+}
+
+} // namespace facebook::torchcodec
diff --git a/src/torchcodec/_core/ValidationUtils.h b/src/torchcodec/_core/ValidationUtils.h
new file mode 100644
index 000000000..ce2d11256
--- /dev/null
+++ b/src/torchcodec/_core/ValidationUtils.h
@@ -0,0 +1,21 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.
+// All rights reserved.
+//
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree.
+
+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include <string>
+
+namespace facebook::torchcodec {
+
+int validateInt64ToInt(int64_t value, const std::string& parameterName);
+
+std::optional<int> validateOptionalInt64ToInt(
+    const std::optional<int64_t>& value,
+    const std::string& parameterName);
+
+} // namespace facebook::torchcodec
diff --git a/src/torchcodec/_core/custom_ops.cpp b/src/torchcodec/_core/custom_ops.cpp
index a5127e73f..c646ed54a 100644
--- a/src/torchcodec/_core/custom_ops.cpp
+++ b/src/torchcodec/_core/custom_ops.cpp
@@ -13,6 +13,7 @@
 #include "src/torchcodec/_core/AVIOTensorContext.h"
 #include "src/torchcodec/_core/Encoder.h"
 #include "src/torchcodec/_core/SingleStreamDecoder.h"
+#include "src/torchcodec/_core/ValidationUtils.h"
 
 namespace facebook::torchcodec {
 
@@ -164,16 +165,6 @@ std::string mapToJson(const std::map<std::string, std::string>& metadataMap) {
   return ss.str();
 }
 
-int validateSampleRate(int64_t sampleRate) {
-  TORCH_CHECK(
-      sampleRate <= std::numeric_limits<int>::max(),
-      "sample_rate=",
-      sampleRate,
-      " is too large to be cast to an int.");
-
-  return static_cast<int>(sampleRate);
-}
-
 } // namespace
 
 // ==============================
@@ -413,14 +404,17 @@ void encode_audio_to_file(
     std::optional<int64_t> bit_rate = std::nullopt,
     std::optional<int64_t> num_channels = std::nullopt,
     std::optional<int64_t> desired_sample_rate = std::nullopt) {
-  // TODO Fix implicit int conversion:
-  // https://github.com/pytorch/torchcodec/issues/679
   AudioStreamOptions audioStreamOptions;
-  audioStreamOptions.bitRate = bit_rate;
-  audioStreamOptions.numChannels = num_channels;
-  audioStreamOptions.sampleRate = desired_sample_rate;
+  audioStreamOptions.bitRate = validateOptionalInt64ToInt(bit_rate, "bit_rate");
+  audioStreamOptions.numChannels =
+      validateOptionalInt64ToInt(num_channels, "num_channels");
+  audioStreamOptions.sampleRate =
+      validateOptionalInt64ToInt(desired_sample_rate, "desired_sample_rate");
   AudioEncoder(
-      samples, validateSampleRate(sample_rate), file_name, audioStreamOptions)
+      samples,
+      validateInt64ToInt(sample_rate, "sample_rate"),
+      file_name,
+      audioStreamOptions)
       .encode();
 }
 
@@ -432,15 +426,15 @@ at::Tensor encode_audio_to_tensor(
     std::optional<int64_t> num_channels = std::nullopt,
     std::optional<int64_t> desired_sample_rate = std::nullopt) {
   auto avioContextHolder = std::make_unique<AVIOToTensorContext>();
-  // TODO Fix implicit int conversion:
-  // https://github.com/pytorch/torchcodec/issues/679
   AudioStreamOptions audioStreamOptions;
-  audioStreamOptions.bitRate = bit_rate;
-  audioStreamOptions.numChannels = num_channels;
-  audioStreamOptions.sampleRate = desired_sample_rate;
+  audioStreamOptions.bitRate = validateOptionalInt64ToInt(bit_rate, "bit_rate");
+  audioStreamOptions.numChannels =
+      validateOptionalInt64ToInt(num_channels, "num_channels");
+  audioStreamOptions.sampleRate =
+      validateOptionalInt64ToInt(desired_sample_rate, "desired_sample_rate");
   return AudioEncoder(
              samples,
-             validateSampleRate(sample_rate),
+             validateInt64ToInt(sample_rate, "sample_rate"),
              format,
              std::move(avioContextHolder),
              audioStreamOptions)
diff --git a/src/torchcodec/_core/pybind_ops.cpp b/src/torchcodec/_core/pybind_ops.cpp
index e74e5574f..72969f7a9 100644
--- a/src/torchcodec/_core/pybind_ops.cpp
+++ b/src/torchcodec/_core/pybind_ops.cpp
@@ -13,6 +13,7 @@
 #include "src/torchcodec/_core/Encoder.h"
 #include "src/torchcodec/_core/SingleStreamDecoder.h"
 #include "src/torchcodec/_core/StreamOptions.h"
+#include "src/torchcodec/_core/ValidationUtils.h"
 
 namespace py = pybind11;
 
@@ -55,20 +56,19 @@ void encode_audio_to_file_like(
   auto samples = torch::from_blob(
       reinterpret_cast<void*>(data_ptr), shape, tensor_options);
 
-  // TODO Fix implicit int conversion:
-  // https://github.com/pytorch/torchcodec/issues/679
-  // same for sample_rate parameter below
   AudioStreamOptions audioStreamOptions;
-  audioStreamOptions.bitRate = bit_rate;
-  audioStreamOptions.numChannels = num_channels;
-  audioStreamOptions.sampleRate = desired_sample_rate;
+  audioStreamOptions.bitRate = validateOptionalInt64ToInt(bit_rate, "bit_rate");
+  audioStreamOptions.numChannels =
+      validateOptionalInt64ToInt(num_channels, "num_channels");
+  audioStreamOptions.sampleRate =
+      validateOptionalInt64ToInt(desired_sample_rate, "desired_sample_rate");
 
   auto avioContextHolder =
       std::make_unique<AVIOFileLikeContext>(file_like, /*isForWriting=*/true);
 
   AudioEncoder encoder(
       samples,
-      static_cast<int>(sample_rate),
+      validateInt64ToInt(sample_rate, "sample_rate"),
       format,
       std::move(avioContextHolder),
       audioStreamOptions);