New jitter buffer experiment.

webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc

Index: webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc
diff --git a/webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc b/webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc
index 8c798db66529b5131d63aaa218e8c6f419cac2e7..1bde7084548928c559aed658841254e2c3c4b4c8 100644
--- a/webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc
+++ b/webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc
@@ -256,6 +256,9 @@ int VP9EncoderImpl::InitEncode(const VideoCodec* inst,
   }
   if (encoder_ == NULL) {
     encoder_ = new vpx_codec_ctx_t;
+    // Random start 16 bits is enough.
+    picture_id_ = static_cast<uint16_t>(rand()) & 0x7FFF;  // NOLINT
+    tl0_pic_idx_ = static_cast<uint8_t>(rand());           // NOLINT

[stefan-webrtc, 2016/11/08 10:41:34]

Not clear to me why this change is done, and why it's in this CL. Please
comment.

[philipel, 2016/11/08 12:28:39]

Done.

[stefan-webrtc, 2016/11/08 14:49:27]

The problem is that if we're relying on this change for the new JB to work,
we'll not be compatible with old Chrome versions. So either we'll have to filter
out VP9 from the experiment for a couple of versions, or we find a way to handle
it on the receiver...

[philipel, 2016/11/10 16:13:53]

Fixed in RtpFrameReferenceFinder

   }
   if (config_ == NULL) {
     config_ = new vpx_codec_enc_cfg_t;
@@ -270,8 +273,6 @@ int VP9EncoderImpl::InitEncode(const VideoCodec* inst,
   if (num_temporal_layers_ == 0)
     num_temporal_layers_ = 1;
 
-  // Random start 16 bits is enough.
-  picture_id_ = static_cast<uint16_t>(rand()) & 0x7FFF;  // NOLINT
   // Allocate memory for encoded image
   if (encoded_image_._buffer != NULL) {
     delete[] encoded_image_._buffer;
@@ -366,8 +367,6 @@ int VP9EncoderImpl::InitEncode(const VideoCodec* inst,
     return WEBRTC_VIDEO_CODEC_ERR_PARAMETER;
   }
 
-  tl0_pic_idx_ = static_cast<uint8_t>(rand());  // NOLINT
-
   return InitAndSetControlSettings(inst);
 }