Ignore Camera and Flip bits in CVO when parsing video rotation

webrtc/common_types.h

Index: webrtc/common_types.h
diff --git a/webrtc/common_types.h b/webrtc/common_types.h
index bb29af0bebe0775054d5ec41dfe8365bb8084f13..b96974428efaca92e329ec200f084ea509030d67 100644
--- a/webrtc/common_types.h
+++ b/webrtc/common_types.h
@@ -785,6 +785,7 @@ struct RTPHeaderExtension {
   // http://www.etsi.org/deliver/etsi_ts/126100_126199/126114/12.07.00_60/
   // ts_126114v120700p.pdf
   bool hasVideoRotation;
+  // This byte actually represents the whole CVO byte: |0 0 0 0 C F R R|.

[danilchap, 2016/08/25 15:54:17]

Another way to fix this bug 
is to change rtp_utility.cc line 400:
header->extension.videoRotation = ptr[0] & 0x03;
then this byte would be rotation only.
(VideoOrientation::Parse is still unused)

[magjed_webrtc, 2016/08/26 07:56:26]

Right. I'm not sure if we should parse the rotation and C/F bits directly in
rtp_utility.cc or not. This seemed like the easiest solution, then I don't need
to remove or change the name of ConvertCVOByteToVideoRotation. We mix the names
"videoRotation", "videoOrientation", and CVO interchangeably in the code, so
it's a bit confusing.

[pthatcher1, 2016/08/29 18:52:59]

I think it makes most sense for videoRotation here to be an enum, like we have
videoRotation in other places.  If it's not an enum, then it should be named
something that makes it clear it is a CVObyte, perhaps calling it |cvo|.  But
giving it a name that sounds like an enum and value that's a cvo-specific byte
is confusing.  

[magjed_webrtc, 2016/08/31 11:06:59]

To be clear, this mixup is not something I added in this CL. It has been like
that since CVO was added here: https://webrtc-codereview.appspot.com/42439004.
Actually, reading the review discussion in that CL, it was you that pushed for
changing the name of this byte from coordinationOfVideoOrientation to
videoRotation.

In the latest patch set, I discard the camera and flip bits of the CVO byte in
order to make videoRotation an enum. It will be future work for someone to parse
and store the camera and flip bits in rtp_utility.cc and
rtp_header_extensions.cc.

   uint8_t videoRotation;
 
   PlayoutDelay playout_delay = {-1, -1};