Configure OpenH264 sSliceArgument.uiSliceNum set to 1.

webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc

Index: webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc
diff --git a/webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc b/webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc
index f29a4895ff181c72c4f5342082d5efb14e147955..defd7503e7046ff54a952dc984f33a234d8bc552 100644
--- a/webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc
+++ b/webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc
@@ -439,13 +439,12 @@ SEncParamExt H264EncoderImpl::CreateEncoderParams() const {
       encoder_params.iTargetBitrate;
   encoder_params.sSpatialLayers[0].iMaxSpatialBitrate =
       encoder_params.iMaxBitrate;
-#if (OPENH264_MAJOR == 1) && (OPENH264_MINOR <= 5)
   // Slice num according to number of threads.
+#if (OPENH264_MAJOR == 1) && (OPENH264_MINOR <= 5)
   encoder_params.sSpatialLayers[0].sSliceCfg.uiSliceMode = SM_AUTO_SLICE;
 #else
-  // When uiSliceMode = SM_FIXEDSLCNUM_SLICE, uiSliceNum = 0 means auto design
-  // it with cpu core number.
-  encoder_params.sSpatialLayers[0].sSliceArgument.uiSliceNum = 0;
+  encoder_params.sSpatialLayers[0].sSliceArgument.uiSliceNum =
+      encoder_params.iMultipleThreadIdc;

[hbos, 2016/10/28 09:01:03]

Do we know that n works if number of threads are n>1? I.e, should this be 1 or
n? In either case we'll notice when n changes from hard-coded 1.

[sprang_webrtc, 2016/10/31 09:22:29]

I tried with 4 thread and uiSliceNum 4 and the rate controller is still borked.
Hard-coding to 1 instead and adding todo about following up on seeming OpenH264
bug.

[hbos, 2016/10/31 09:23:33]

sgtm

   encoder_params.sSpatialLayers[0].sSliceArgument.uiSliceMode =
       SM_FIXEDSLCNUM_SLICE;
 #endif