Show error message if ffplay missing (not just ffmpeg) (#168)

corrscope/gui/__init__.py

@@ -984,7 +984,7 @@ class DownloadFFmpegActivity:
     path_uri = qc.QUrl.fromLocalFile(paths.PATH_dir).toString()
 
     required = (
-        f"FFmpeg must be in PATH or "
+        f"FFmpeg+FFplay must be in PATH or "
         f'<a href="{path_uri}">corrscope folder</a> in order to use corrscope.<br>'
     )
 

corrscope/outputs.py

@@ -107,7 +107,7 @@ class _FFmpegProcess:
             return subprocess.Popen(
                 args, stdin=subprocess.PIPE, bufsize=bufsize, **kwargs
             )
-        except FileNotFoundError as e:
+        except FileNotFoundError:
             raise MissingFFmpegError()
 
     def _generate_args(self) -> List[str]:
@@ -261,7 +261,10 @@ class FFplayOutput(PipeOutput):
         p1 = ffmpeg.popen(["-"], self.bufsize, stdout=subprocess.PIPE)
 
         ffplay = shlex.split("ffplay -autoexit -") + FFMPEG_QUIET
-        p2 = subprocess.Popen(ffplay, stdin=p1.stdout)
+        try:
+            p2 = subprocess.Popen(ffplay, stdin=p1.stdout)
+        except FileNotFoundError:
+            raise MissingFFmpegError()
 
         p1.stdout.close()
         # assert p2.stdin is None   # True unless Popen is being mocked (test_output).

corrscope/settings/paths.py

@@ -53,7 +53,9 @@ class MissingFFmpegError(CorrError):
     ffmpeg_url = get_ffmpeg_url()
     can_download = bool(ffmpeg_url)
 
-    message = f'FFmpeg must be in PATH or "{PATH_dir}" in order to use corrscope.\n'
+    message = (
+        f'FFmpeg+FFplay must be in PATH or "{PATH_dir}" in order to use corrscope.\n'
+    )
 
     if can_download:
         message += f"Download ffmpeg from {ffmpeg_url}."