diff --git a/musicalgestures/_motionvideo.py b/musicalgestures/_motionvideo.py
index 98da0034..9efb2ebd 100644
--- a/musicalgestures/_motionvideo.py
+++ b/musicalgestures/_motionvideo.py
@@ -310,8 +310,11 @@ def mg_motion(
             self.motiongram_vertical_image = MgImage(target_name_mgx)
             self.motiongram_horizontal_image = MgImage(target_name_mgy)
 
+        # `audio_descriptors` arrives as a flag and travels on as the video to read
+        # audio from, which save_analysis expects. Two meanings, two names.
+        audio_descriptors_source: "bool | musicalgestures.MgVideo" = audio_descriptors
         if audio_descriptors:
-            audio_descriptors = self
+            audio_descriptors_source = self
             
         if save_data:
             # `normalize` was declared on mg_motion and never used. It now
@@ -327,7 +330,7 @@ def mg_motion(
             if title is None:
                 title = os.path.basename(of + fex)
             # save plot as an MgImage at motion_plot_image for parent MgVideo
-            self.motion_plot_image = MgImage(save_analysis(of, self.fps, aom, com, qom, motion_analysis, audio_descriptors, self.width,
+            self.motion_plot_image = MgImage(save_analysis(of, self.fps, aom, com, qom, motion_analysis, audio_descriptors_source, self.width,
                                         self.height, unit, title, target_name_plot=target_name_plot, overwrite=overwrite))
                 
         # Resetting numpy warnings for dividing by 0
diff --git a/musicalgestures/_posetools.py b/musicalgestures/_posetools.py
index 0af52143..b1a9111e 100644
--- a/musicalgestures/_posetools.py
+++ b/musicalgestures/_posetools.py
@@ -225,6 +225,8 @@ def _read_result(lms, wlms):
     frame_bytes = w * h * 3
     stopped_early = False
     proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    # stdout=PIPE guarantees a stream; the annotation is Optional for the general case
+    assert proc.stdout is not None, "ffmpeg was started without a readable output stream"
     # Drain FFmpeg's stderr on a background thread as it is produced, rather
     # than only reading it in the `finally` block below: the stdout-reading
     # loop can run far longer than the OS pipe buffer takes to fill (a few
diff --git a/musicalgestures/_ssm.py b/musicalgestures/_ssm.py
index db654829..c60a6c66 100644
--- a/musicalgestures/_ssm.py
+++ b/musicalgestures/_ssm.py
@@ -544,6 +544,7 @@ def mg_ssm(
 
     else:
         print(f'Unrecognized feature: "{features}". Try "motiongrams", "videograms, "spectrogram", "chromagram" or "tempogram".')
+        return None
 
 
 
diff --git a/musicalgestures/_stream.py b/musicalgestures/_stream.py
index 78229c7d..7dbac751 100644
--- a/musicalgestures/_stream.py
+++ b/musicalgestures/_stream.py
@@ -148,6 +148,8 @@ def __enter__(self) -> "MgVideoReader":
         self._process = subprocess.Popen(
             cmd, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL, bufsize=-1
         )
+        # stdout=PIPE guarantees a stream; the annotation is Optional for the general case
+        assert self._process.stdout is not None, "ffmpeg was started without a readable output stream"
         self._frame_index = 0
         return self
 
diff --git a/musicalgestures/_utils.py b/musicalgestures/_utils.py
index 85e6885e..c8c28eb5 100644
--- a/musicalgestures/_utils.py
+++ b/musicalgestures/_utils.py
@@ -271,7 +271,7 @@ class MgFigure():
     Class for working with figures and plots within the Musical Gestures Toolbox.
     """
 
-    def __init__(self, figure=None, figure_type: str | None = None, data: dict | None = None,
+    def __init__(self, figure=None, figure_type: str | None = None, data: Any = None,
                  layers: list | None = None, image=None):
         """
         Initializes the MgFigure object.
diff --git a/musicalgestures/_videoadjust.py b/musicalgestures/_videoadjust.py
index d82a58a6..934d9187 100644
--- a/musicalgestures/_videoadjust.py
+++ b/musicalgestures/_videoadjust.py
@@ -1,6 +1,7 @@
 import numpy as np
 import cv2
 import os
+import musicalgestures
 from musicalgestures._utils import scale_num, get_length, ffmpeg_cmd, has_audio, generate_outfilename, convert_to_mp4