diff --git a/CHANGELOG.md b/CHANGELOG.md
index f4a2092..56372f2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Improve the CMake optimization flags and option names.
 
+### Fixed
+
+- A bug that causes the wrong encoder to be selected.
+
 ## [6.3.1] - 2024-12-21
 
 ### Fixed
diff --git a/include/libvideo2x/encoder.h b/include/libvideo2x/encoder.h
index fba93a5..c485c1d 100644
--- a/include/libvideo2x/encoder.h
+++ b/include/libvideo2x/encoder.h
@@ -10,15 +10,13 @@ extern "C" {
 #include <libavutil/pixdesc.h>
 }
 
-#include "fsutils.h"
-
 namespace video2x {
 namespace encoder {
 
 // Encoder configurations
 struct EncoderConfig {
     // Non-AVCodecContext options
-    AVCodecID codec = AV_CODEC_ID_NONE;
+    std::string codec = "libx264";
     bool copy_streams = true;
 
     // Basic video options
@@ -45,7 +43,7 @@ struct EncoderConfig {
     int delay = -1;
 
     // Extra AVOptions
-    std::vector<std::pair<fsutils::StringType, fsutils::StringType>> extra_opts;
+    std::vector<std::pair<std::string, std::string>> extra_opts;
 };
 
 class Encoder {
diff --git a/src/encoder.cpp b/src/encoder.cpp
index 7954e9c..48a90b3 100644
--- a/src/encoder.cpp
+++ b/src/encoder.cpp
@@ -53,11 +53,9 @@ int Encoder::init(
     }
 
     // Find the encoder
-    const AVCodec* encoder = avcodec_find_encoder(enc_cfg.codec);
+    const AVCodec* encoder = avcodec_find_encoder_by_name(enc_cfg.codec.c_str());
     if (!encoder) {
-        logger()->error(
-            "Required video encoder not found for codec {}", avcodec_get_name(enc_cfg.codec)
-        );
+        logger()->error("Could not find encoder '{}'", enc_cfg.codec);
         return AVERROR_ENCODER_NOT_FOUND;
     }
 
@@ -151,8 +149,8 @@ int Encoder::init(
 
     // Set extra AVOptions
     for (const auto& [opt_name, opt_value] : enc_cfg.extra_opts) {
-        std::string opt_name_str = fsutils::wstring_to_u8string(opt_name);
-        std::string opt_value_str = fsutils::wstring_to_u8string(opt_value);
+        std::string opt_name_str = opt_name;
+        std::string opt_value_str = opt_value;
         logger()->debug("Setting encoder option '{}' to '{}'", opt_name_str, opt_value_str);
 
         ret = av_opt_set(enc_ctx_->priv_data, opt_name_str.c_str(), opt_value_str.c_str(), 0);
diff --git a/tools/video2x/src/argparse.cpp b/tools/video2x/src/argparse.cpp
index 54218c1..2dad38a 100644
--- a/tools/video2x/src/argparse.cpp
+++ b/tools/video2x/src/argparse.cpp
@@ -307,18 +307,15 @@ int parse_args(
         }
 
         // Parse codec to AVCodec
-        enc_cfg.codec = AV_CODEC_ID_H264;
+        enc_cfg.codec = "libx264";
         if (vm.count("codec")) {
-            video2x::fsutils::StringType codec_str = vm["codec"].as<video2x::fsutils::StringType>();
-            const AVCodec* codec =
-                avcodec_find_encoder_by_name(wstring_to_u8string(codec_str).c_str());
-            if (codec == nullptr) {
-                video2x::logger()->critical(
-                    "Codec '{}' not found.", wstring_to_u8string(codec_str)
-                );
+            std::string codec_str =
+                wstring_to_u8string(vm["codec"].as<video2x::fsutils::StringType>());
+            if (avcodec_find_encoder_by_name(codec_str.c_str()) == nullptr) {
+                video2x::logger()->critical("Invalid encoder '{}'.", codec_str);
                 return -1;
             }
-            enc_cfg.codec = codec->id;
+            enc_cfg.codec = codec_str;
         }
 
         // Parse copy streams flag
@@ -348,7 +345,9 @@ int parse_args(
                 if (eq_pos != video2x::fsutils::StringType::npos) {
                     video2x::fsutils::StringType key = opt.substr(0, eq_pos);
                     video2x::fsutils::StringType value = opt.substr(eq_pos + 1);
-                    enc_cfg.extra_opts.push_back(std::make_pair(key, value));
+                    enc_cfg.extra_opts.push_back(
+                        std::make_pair(wstring_to_u8string(key), wstring_to_u8string(value))
+                    );
                 } else {
                     video2x::logger()->critical(
                         "Invalid extra AVOption format: {}", wstring_to_u8string(opt)