diff --git a/build/bytetrack-counter b/build/bytetrack-counter
index 79dc1e2..dfd9847 100755
Binary files a/build/bytetrack-counter and b/build/bytetrack-counter differ
diff --git a/build/version.hpp b/build/version.hpp
index d00ff13..902d53e 100644
--- a/build/version.hpp
+++ b/build/version.hpp
@@ -4,11 +4,11 @@
 
 namespace version {
 
-const std::string GIT_COMMIT   = "37f98f24";
+const std::string GIT_COMMIT   = "ef17a910";
 const std::string GIT_BRANCH   = "main";
 const std::string GIT_TAG      = "";
-const std::string BUILD_DATE   = "2026-08-05";
-const std::string BUILD_TIME   = "00:25:19";
+const std::string BUILD_DATE   = "2026-08-07";
+const std::string BUILD_TIME   = "23:10:08";
 const int         BUILD_YEAR   = 2026;
 const bool        BUILD_RKNN   = 1;
 
diff --git a/config.env.example b/config.env.example
index 32fbbf2..0e67874 100644
--- a/config.env.example
+++ b/config.env.example
@@ -142,6 +142,11 @@ RECORD_DELAY_SECONDS=10
 RECORD_END_DELAY=1
 # Days to keep recorded video folders (folders older than this deleted on startup)
 RECORD_RETENTION_DAYS=3
+# H.264 quality: lower CRF = higher quality (17-18 ~ visually lossless, 23 is ffmpeg default).
+# Leave empty to use ffmpeg default.
+RECORD_CRF=18
+# x264 preset: slow = better compression/quality at higher CPU cost. Empty = default (medium).
+RECORD_PRESET=slow
 # Shared memory directory — used for video recording, live snapshots, and .reset trigger
 # RECORD_SHM_DIR is an alias; SHM_DIR takes priority if both set
 SHM_DIR=/dev/shm/bytetrack-counter
diff --git a/src/config.cpp b/src/config.cpp
index 0a2f623..cfa8031 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -146,6 +146,9 @@ void AppConfig::load_from_env(const char* env_path) {
     if (!reds_s.empty()) record_end_delay_seconds = std::stof(reds_s);
     auto rret_s = get_env("RECORD_RETENTION_DAYS");
     if (!rret_s.empty()) record_retention_days = std::stoi(rret_s);
+    auto rcrf_s = get_env("RECORD_CRF");
+    if (!rcrf_s.empty()) record_crf = std::stoi(rcrf_s);
+    record_preset = get_env("RECORD_PRESET", record_preset);
     shm_dir = get_env("RECORD_SHM_DIR", shm_dir);
     shm_dir = get_env("SHM_DIR", shm_dir);
 
diff --git a/src/config.hpp b/src/config.hpp
index 1ecaf51..423f73e 100644
--- a/src/config.hpp
+++ b/src/config.hpp
@@ -64,6 +64,8 @@ struct AppConfig {
     float record_delay_seconds = 10.0f;
     float record_end_delay_seconds = 1.0f;
     int record_retention_days = 3;
+    int record_crf = -1;
+    std::string record_preset;
     std::string shm_dir = "/dev/shm/bytetrack-counter";
 
     bool live_stream_enabled = false;
diff --git a/src/main.cpp b/src/main.cpp
index d145db0..39e2611 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -264,7 +264,9 @@ int main(int argc, char* argv[]) {
             w, h, static_cast<int>(fps_prop),
             g_config.record_delay_seconds,
             g_config.record_end_delay_seconds,
-            g_config.record_retention_days);
+            g_config.record_retention_days,
+            g_config.record_crf,
+            g_config.record_preset);
         auto* vw = video_writer.get();
         store.set_batch_closed_callback([vw](int bn, const std::string& date) { vw->on_batch_closed(bn, date); });
     }
diff --git a/src/video_writer.cpp b/src/video_writer.cpp
index db3aa45..37fe326 100644
--- a/src/video_writer.cpp
+++ b/src/video_writer.cpp
@@ -16,11 +16,13 @@ VideoBatchWriter::VideoBatchWriter(const std::string& shm_dir,
                                    int w, int h, int fps,
                                    float delay_sec,
                                    float end_delay_sec,
-                                   int retention_days)
+                                   int retention_days,
+                                   int crf,
+                                   const std::string& preset)
     : shm_dir_(shm_dir), output_dir_(output_dir),
       w_(w), h_(h), fps_(fps),
       delay_sec_(delay_sec), end_delay_sec_(end_delay_sec),
-      retention_days_(retention_days)
+      retention_days_(retention_days), crf_(crf), preset_(preset)
 {
     ensure_dir(shm_dir_);
     ensure_dir(output_dir_);
@@ -135,6 +137,16 @@ void VideoBatchWriter::start_recording() {
          << std::put_time(std::localtime(&t), "%Y%m%d_%H%M%S") << ".mp4";
     current_path_ = shm_dir_ + "/" + name.str();
 
+    if (crf_ > 0 || !preset_.empty()) {
+        std::string opts;
+        if (crf_ > 0) opts += "crf;" + std::to_string(crf_);
+        if (!preset_.empty()) {
+            if (!opts.empty()) opts += "|";
+            opts += "preset;" + preset_;
+        }
+        setenv("OPENCV_FFMPEG_WRITE_OPTIONS", opts.c_str(), 1);
+    }
+
     writer_.open(current_path_,
                  cv::VideoWriter::fourcc('a','v','c','1'),
                  fps_, cv::Size(w_, h_));
diff --git a/src/video_writer.hpp b/src/video_writer.hpp
index 6d67196..37463ef 100644
--- a/src/video_writer.hpp
+++ b/src/video_writer.hpp
@@ -10,7 +10,9 @@ public:
                      int w, int h, int fps,
                      float delay_sec,
                      float end_delay_sec,
-                     int retention_days);
+                     int retention_days,
+                     int crf,
+                     const std::string& preset);
 
     ~VideoBatchWriter();
 
@@ -35,6 +37,8 @@ private:
     float delay_sec_;
     float end_delay_sec_;
     int retention_days_;
+    int crf_;
+    std::string preset_;
 
     State state_ = IDLE;
     std::chrono::steady_clock::time_point state_start_;