把摄像头协商结果记进 session.json，并在达不到配置帧率时明说 - What: sdk_worker 新增 capture_status_of(sensor)（把采集源的 config 与 status 合成 {requested:{width,height,fps,fourcc}, negotiated:{width,height,fps,fourcc,backend}, dropped_frames}）与 short_capture_fallacy(status)（当协商帧率低于申请值 90% 时给出一句话描述，含分辨率/实际帧率/申请帧率/格式/后端；两者都齐全时才说话）；两个 worker 都加 capture_status() 访问器（box 取当前 sensor，finger 取 runtime.tactile.raw_sensor）。app_window：session.json 新增顶层 capture 块（_capture_metadata()，走同一个访问器）；新增 _check_capture_negotiation()——每个会话在驱动第一次报出速率后检查一次，达不到就通过 _notify 明确提示（不是每帧刷屏），新键 status.capture_slow（中英）写明"软件改不了、记录按实际帧率保存、请降分辨率/换格式或换摄像头"。tests/test_worker_frame_rate.py：假设备补上 CaptureConfig 与 CaptureStatus 的 width/height/fps/fourcc/backend_name 字段，新增 test_a_low_camera_rate_is_recorded_as_a_negotiation（1920x1080、申请 30、协商 16.67 时 capture_status() 两半都在、描述里含 1920x1080/16.67/30；协商到位时描述为空串）。 - Why: 用户按上一轮的读数报告"还是摄像头 16.7"，即摄像头自身只发布 16.7 —— 这排除了流水线（每帧只 12 ms）与应用侧节拍，剩下的只能是采集格式协商：配置申请的是 resolution_raw 1920x1080 @ 30 fps（fourcc 走 CaptureConfig 默认 MJPG）。这类"驱动只提供这个格式"的情况软件无法改变，但记录里必须留下证据、操作员必须被告知，否则一个 16.7 的采集和一次正常的 30 fps 采集在文件里长得一样，事后再也无法解释。 - Verification: shared 全量 161 passed（新增 1 项）；studio 90 passed；ui_check 554 项检查 0 失败；locale_check 287 字面键全部命中、中英键集一致（343+1=344? 见下方键数）。 - Not in this change: 未改 SDK 的采集参数（仍是 1920x1080/30/MJPG、后端 auto）；frames.csv 仍未记录 process_ms/capture_fps（下次改记录格式时一并加）；未做自动降级（例如检测到 16.7 就自动改用更低分辨率）——那会改变传感器几何，必须由人决定。

shared/src/orisys_app_shared/acquisition/finger_worker.py

@@ -27,6 +27,7 @@ from orisys_app_shared.acquisition.sdk_worker import (
     STOP_JOIN_TIMEOUT_S,
     VIDEO_EOF_TIMEOUT_S,
     calibration_digest,
+    capture_status_of,
     loaded_calibration_version,
     loaded_path,
     process_chain,
@@ -126,6 +127,14 @@ class FingerAcquisitionWorker(RecordSinkMixin):
         with self._lock:
             return tuple(self._filters_unsupported)
 
+    def capture_status(self) -> dict:
+        """What the camera was asked for, and what the driver actually gave."""
+        with self._lock:
+            runtime = next(iter(self._runtimes.values()), None)
+        tactile = getattr(runtime, "tactile", None) if runtime is not None else None
+        raw_sensor = getattr(tactile, "raw_sensor", None) if tactile is not None else None
+        return capture_status_of(raw_sensor)
+
     @property
     def is_running(self) -> bool:
         return self._thread is not None and self._thread.is_alive()

shared/src/orisys_app_shared/acquisition/sdk_worker.py

@@ -11,7 +11,7 @@ import threading
 import time
 from dataclasses import dataclass
 from pathlib import Path
-from typing import Callable, Optional
+from typing import Any, Callable, Mapping, Optional
 
 import cv2
 import numpy as np
@@ -84,6 +84,7 @@ __all__ = [
     "SdkPacket",
     "SdkAcquisitionWorker",
     "calibration_digest",
+    "capture_status_of",
     "load_fixed_mode",
     "loaded_calibration_version",
     "loaded_path",
@@ -91,6 +92,7 @@ __all__ = [
     "process_chain",
     "read_depth",
     "read_forces_from_sensor",
+    "short_capture_fallacy",
 ]
 
 
@@ -155,6 +157,77 @@ def _capture_source(sensor):
     return source
 
 
+def capture_status_of(sensor) -> dict:
+    """Requested vs negotiated capture parameters, or ``{}`` when unknown.
+
+    ``requested`` comes from the capture config the SDK was handed (built from the
+    sensor.json's ``camera`` block); ``negotiated`` is what OpenCV/the driver
+    reported back after the stream properties were applied. They disagree exactly
+    when a camera cannot do what the config asks for.
+    """
+    source = _capture_source(sensor) if sensor is not None else None
+    if source is None:
+        return {}
+    status = getattr(source, "status", None)
+    config = getattr(source, "config", None)
+    if status is None and config is None:
+        return {}
+
+    def _value(obj, name, default=None):
+        return getattr(obj, name, default) if obj is not None else default
+
+    dropped = _value(status, "dropped_frames", 0)
+    return {
+        "requested": {
+            "width": _value(config, "width"),
+            "height": _value(config, "height"),
+            "fps": _value(config, "fps"),
+            "fourcc": _value(config, "fourcc"),
+        },
+        "negotiated": {
+            "width": _value(status, "width"),
+            "height": _value(status, "height"),
+            "fps": _value(status, "fps"),
+            "fourcc": _value(status, "fourcc"),
+            "backend": _value(status, "backend_name"),
+        },
+        "dropped_frames": int(dropped or 0),
+    }
+
+
+def short_capture_fallacy(status: Mapping[str, Any] | None) -> str:
+    """A one-line description of a capture negotiation that fell short.
+
+    Empty when the driver gave what was asked for (or when either half is
+    unknown): this exists to be *said*, not to fill a field.
+    """
+    if not isinstance(status, Mapping):
+        return ""
+    requested = dict(status.get("requested") or {})
+    negotiated = dict(status.get("negotiated") or {})
+    wanted = requested.get("fps")
+    got = negotiated.get("fps")
+    try:
+        wanted_value = float(wanted)
+        got_value = float(got)
+    except (TypeError, ValueError):
+        return ""
+    if wanted_value <= 0 or got_value <= 0 or got_value >= wanted_value * 0.9:
+        return ""
+    size = ""
+    width, height = negotiated.get("width"), negotiated.get("height")
+    if width and height:
+        size = f"{int(width)}x{int(height)} "
+    fourcc = str(negotiated.get("fourcc") or "").strip()
+    backend = str(negotiated.get("backend") or "").strip()
+    detail = "/".join(part for part in (fourcc, backend) if part)
+    return (
+        f"the camera negotiated {size}@{got_value:g} fps "
+        f"(the config asks for {wanted_value:g})"
+        + (f" [{detail}]" if detail else "")
+    )
+
+
 def process_chain(sensor) -> tuple[Optional[np.ndarray], str]:
     """Run the live processing chain for one already-read frame.
 
@@ -466,6 +539,18 @@ class SdkAcquisitionWorker(RecordSinkMixin):
         with self._lock:
             return tuple(self._filters_unsupported)
 
+    def capture_status(self) -> dict:
+        """What the camera was asked for, and what the driver actually gave.
+
+        The negotiation is where a camera that cannot do the configured frame
+        rate is decided, and nothing downstream can turn 16.7 fps back into 30.
+        Recording both halves is what lets a recording explain its own frame
+        rate instead of leaving the operator to guess.
+        """
+        with self._lock:
+            sensor = next(iter(self._sensors.values()), None)
+        return capture_status_of(sensor)
+
     @property
     def is_running(self) -> bool:
         return self._thread is not None and self._thread.is_alive()