Allow presets to specify custom elements to apply transformations to …

…the video stream. This allows you to rotate, for example, by setting "transform": "videoflip method=clockwise" in the JSON device preset. Since any element can be used and you are modifying raw video this can also be used to add effects, color balance, sharpen, etc.

arista/presets.py

@@ -233,6 +233,7 @@ def json(self):
                     "passes": preset.vcodec.passes,
                     "width": preset.vcodec.width,
                     "height": preset.vcodec.height,
+                    "transform": preset.vcodec.transform,
                 },
             })
 
@@ -279,6 +280,7 @@ def from_json(data):
                     "passes": vcodec.get("passes", []),
                     "width": vcodec.get("width", []),
                     "height": vcodec.get("height", []),
+                    "transform": vcodec.get("transform", ""),
                 }),
                 "device": device,
             })
@@ -426,11 +428,12 @@ class VideoCodec(Codec):
     """
         Settings for encoding video.
     """
-    def __init__(self, name=None, container=None, rate=None, passes=None, width=None, height=None):
+    def __init__(self, name=None, container=None, rate=None, passes=None, width=None, height=None, transform=None):
         Codec.__init__(self, name=name, container=container, passes=passes)
         self.rate = rate and rate or (Fraction("1"), Fraction("60"))
         self.width = width and width or (2, 1920)
         self.height = height and height or (2, 1080)
+        self.transform = transform
 
 def load(filename):
     """

arista/transcoder.py

@@ -459,6 +459,10 @@ def _setup_pass(self):
             if self.options.deinterlace:
                 deint = " ffdeinterlace ! "
 
+            transform = ""
+            if self.preset.vcodec.transform:
+                transform = self.preset.vcodec.transform + " ! "
+
             sub = ""
             if self.options.subfile:
                 # Render subtitles onto the video stream
@@ -475,9 +479,10 @@ def _setup_pass(self):
                     vmux += "video_%d"
 
             cmd += " dmux. ! queue ! ffmpegcolorspace ! videorate !" \
-                   "%s %s videoscale ! %s ! %s%s ! tee " \
+                   "%s %s %s videoscale ! %s ! %s%s ! tee " \
                    "name=videotee ! queue ! %s" % \
-                   (deint, sub, self.vcaps.to_string(), vbox, vencoder, vmux)
+                   (deint, transform, sub, self.vcaps.to_string(), vbox,
+                    vencoder, vmux)
 
         if self.info.is_audio and self.preset.acodec and \
            self.enc_pass == len(self.preset.vcodec.passes) - 1: