Improve FfmpegOutput shutdown if there's an error in the Ffmpeg process

Set a flag to stop us continually re-trying when it's already failed,
but leave the tidying up proper to the stop() method. This stops us
seeing a few mildly disconcerting errors (unless we want to, of
course).

Signed-off-by: David Plowman <david.plowman@raspberrypi.com>

Author: davidplowman

picamera2/outputs/ffmpegoutput.py

@@ -37,6 +37,7 @@ def __init__(self, output_filename, audio=False, audio_device="default", audio_s
                  audio_samplerate=48000, audio_codec="aac", audio_bitrate=128000, audio_filter=None, pts=None):
         super().__init__(pts=pts)
         self.ffmpeg = None
+        self.output_broken = False
         self.output_filename = output_filename
         self.audio = audio
         self.audio_device = audio_device
@@ -86,7 +87,10 @@ def start(self):
     def stop(self):
         super().stop()
         if self.ffmpeg is not None:
-            self.ffmpeg.stdin.close()  # FFmpeg needs this to shut down tidily
+            try:
+                self.ffmpeg.stdin.close()  # FFmpeg needs this to shut down tidily
+            except Exception:
+                pass
             try:
                 # Give it a moment to flush out video frames, but after that make sure we terminate it.
                 self.ffmpeg.wait(timeout=self.timeout)
@@ -103,13 +107,15 @@ def stop(self):
     def outputframe(self, frame, keyframe=True, timestamp=None, packet=None, audio=False):
         if audio:
             raise RuntimeError("FfmpegOutput does not support audio packets from Picamera2")
-        if self.recording and self.ffmpeg:
+        if self.recording and not self.output_broken:
             # Handle the case where the FFmpeg prcoess has gone away for reasons of its own.
             try:
                 self.ffmpeg.stdin.write(frame)
                 self.ffmpeg.stdin.flush()  # forces every frame to get timestamped individually
             except Exception as e:  # presumably a BrokenPipeError? should we check explicitly?
-                self.ffmpeg = None
+                # Don't clear up the ffmpeg process here, that's what stop() is for. But
+                # set a flag so that we don't keep coming back and re-trying to no avail...
+                self.output_broken = True
                 if self.error_callback:
                     self.error_callback(e)
             else: