good progress

cht/stream/ffmpeg.py

@@ -117,6 +117,18 @@ def extract_scene_frames(input_path, output_dir, scene_threshold=0.10,
     return stdout.decode("utf-8", errors="replace"), stderr.decode("utf-8", errors="replace")
 
 
+def extract_frame_at(input_path, output_path, timestamp):
+    """Extract a single frame at the given timestamp."""
+    output = (
+        ffmpeg.input(str(input_path), ss=timestamp)
+        .output(str(output_path), vframes=1, **{"q:v": "2"})
+        .overwrite_output()
+        .global_args(*QUIET_ARGS)
+    )
+    log.info("extract_frame_at: %s", " ".join(output.compile()))
+    output.run(capture_stdout=True, capture_stderr=True)
+
+
 def run_async(output_node, pipe_stdout=False, pipe_stderr=False):
     """Start an ffmpeg pipeline asynchronously via ffmpeg-python's run_async."""
     log.info("run_async: %s", " ".join(output_node.compile()))