Encoding panel clarifications

The encoding panel mentions "None" in a few places, which is confusing.
- "Codec: None" now reads "No Video"
- "Audio Codec: None" now reads "No Audio"
- "Output Quality: None; ..." now reads "Constant Bitrate"

When selecting "No Video" the remaining video encoding options are
hidden, making it even more explicit that there will not be video in the
output file.

The label "Codec" now reads "Video Codec" for symmetry with "Audio
Codec".

release/scripts/startup/bl_ui/properties_render.py

@@ -434,12 +434,32 @@ class RENDER_PT_encoding(RenderButtonsPanel, Panel):
         split.prop(rd.ffmpeg, "format")
         split.prop(ffmpeg, "use_autosplit")
 
+        # Video:
         layout.separator()
+        self.draw_vcodec(context)
+
+        # Audio:
+        layout.separator()
+        if ffmpeg.format != 'MP3':
+            layout.prop(ffmpeg, "audio_codec", text="Audio Codec")
+
+        if ffmpeg.audio_codec != 'NONE':
+            row = layout.row()
+            row.prop(ffmpeg, "audio_bitrate")
+            row.prop(ffmpeg, "audio_volume", slider=True)
+
+    def draw_vcodec(self, context):
+        """Video codec options."""
+        layout = self.layout
+        ffmpeg = context.scene.render.ffmpeg
 
         needs_codec = ffmpeg.format in {'AVI', 'QUICKTIME', 'MKV', 'OGG', 'MPEG4'}
         if needs_codec:
             layout.prop(ffmpeg, "codec")
 
+        if needs_codec and ffmpeg.codec == 'NONE':
+            return
+
         if ffmpeg.codec in {'DNXHD'}:
             layout.prop(ffmpeg, "use_lossless_output")
 
@@ -473,17 +493,6 @@ class RENDER_PT_encoding(RenderButtonsPanel, Panel):
             col.prop(ffmpeg, "muxrate", text="Rate")
             col.prop(ffmpeg, "packetsize", text="Packet Size")
 
-        layout.separator()
-
-        # Audio:
-        if ffmpeg.format != 'MP3':
-            layout.prop(ffmpeg, "audio_codec", text="Audio Codec")
-
-        if ffmpeg.audio_codec != 'NONE':
-            row = layout.row()
-            row.prop(ffmpeg, "audio_bitrate")
-            row.prop(ffmpeg, "audio_volume", slider=True)
-
 
 class RENDER_PT_bake(RenderButtonsPanel, Panel):
     bl_label = "Bake"