From 59a01b0693b242c6a0c937b0ade8a6748ade8740 Mon Sep 17 00:00:00 2001
From: Qiang Chen <qiangchen@chromium.org>
Date: Mon, 19 Nov 2018 10:30:04 -0800
Subject: [PATCH] Set Framerate in RTCVideoEncoderH264
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This CL utilizes the input frame rate in the RTCVideoEncoderH264, by setting it into VT Property.

The main purpose is to guide VT encoder to make correct decision of the encoded frame size.

Bug: webrtc:10015
Change-Id: Id5c89f2876539f3181030f49b546326fc40b8ea3
Reviewed-on: https://webrtc-review.googlesource.com/c/111420
Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25724}
---
 .../video_codec/RTCVideoEncoderH264.mm        | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/sdk/objc/components/video_codec/RTCVideoEncoderH264.mm b/sdk/objc/components/video_codec/RTCVideoEncoderH264.mm
index 16ad1ff47a..f6690b6d86 100644
--- a/sdk/objc/components/video_codec/RTCVideoEncoderH264.mm
+++ b/sdk/objc/components/video_codec/RTCVideoEncoderH264.mm
@@ -284,6 +284,7 @@ CFStringRef ExtractProfile(webrtc::SdpVideoFormat videoFormat) {
   RTCVideoCodecInfo *_codecInfo;
   std::unique_ptr<webrtc::BitrateAdjuster> _bitrateAdjuster;
   uint32_t _targetBitrateBps;
+  uint32_t _encoderFrameRate;
   uint32_t _encoderBitrateBps;
   RTCH264PacketizationMode _packetizationMode;
   CFStringRef _profile;
@@ -333,6 +334,7 @@ CFStringRef ExtractProfile(webrtc::SdpVideoFormat videoFormat) {
   // We can only set average bitrate on the HW encoder.
   _targetBitrateBps = settings.startBitrate * 1000;  // startBitrate is in kbps.
   _bitrateAdjuster->SetTargetBitrateBps(_targetBitrateBps);
+  _encoderFrameRate = settings.maxFramerate;
 
   // TODO(tkchin): Try setting payload size via
   // kVTCompressionPropertyKey_MaxH264SliceBytes.
@@ -432,7 +434,7 @@ CFStringRef ExtractProfile(webrtc::SdpVideoFormat videoFormat) {
   encodeParams->codecSpecificInfo.packetizationMode = _packetizationMode;
 
   // Update the bitrate if needed.
-  [self setBitrateBps:_bitrateAdjuster->GetAdjustedBitrateBps()];
+  [self setBitrateBps:_bitrateAdjuster->GetAdjustedBitrateBps() frameRate:_encoderFrameRate];
 
   OSStatus status = VTCompressionSessionEncodeFrame(_compressionSession,
                                                     pixelBuffer,
@@ -468,7 +470,7 @@ CFStringRef ExtractProfile(webrtc::SdpVideoFormat videoFormat) {
 - (int)setBitrate:(uint32_t)bitrateKbit framerate:(uint32_t)framerate {
   _targetBitrateBps = 1000 * bitrateKbit;
   _bitrateAdjuster->SetTargetBitrateBps(_targetBitrateBps);
-  [self setBitrateBps:_bitrateAdjuster->GetAdjustedBitrateBps()];
+  [self setBitrateBps:_bitrateAdjuster->GetAdjustedBitrateBps() frameRate:framerate];
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
@@ -616,7 +618,7 @@ CFStringRef ExtractProfile(webrtc::SdpVideoFormat videoFormat) {
   SetVTSessionProperty(_compressionSession, kVTCompressionPropertyKey_RealTime, true);
   SetVTSessionProperty(_compressionSession, kVTCompressionPropertyKey_ProfileLevel, _profile);
   SetVTSessionProperty(_compressionSession, kVTCompressionPropertyKey_AllowFrameReordering, false);
-  [self setEncoderBitrateBps:_targetBitrateBps];
+  [self setEncoderBitrateBps:_targetBitrateBps frameRate:_encoderFrameRate];
   // TODO(tkchin): Look at entropy mode and colorspace matrices.
   // TODO(tkchin): Investigate to see if there's any way to make this work.
   // May need it to interop with Android. Currently this call just fails.
@@ -644,15 +646,17 @@ CFStringRef ExtractProfile(webrtc::SdpVideoFormat videoFormat) {
   return @"VideoToolbox";
 }
 
-- (void)setBitrateBps:(uint32_t)bitrateBps {
-  if (_encoderBitrateBps != bitrateBps) {
-    [self setEncoderBitrateBps:bitrateBps];
+- (void)setBitrateBps:(uint32_t)bitrateBps frameRate:(uint32_t)frameRate {
+  if (_encoderBitrateBps != bitrateBps || _encoderFrameRate != frameRate) {
+    [self setEncoderBitrateBps:bitrateBps frameRate:frameRate];
   }
 }
 
-- (void)setEncoderBitrateBps:(uint32_t)bitrateBps {
+- (void)setEncoderBitrateBps:(uint32_t)bitrateBps frameRate:(uint32_t)frameRate {
   if (_compressionSession) {
     SetVTSessionProperty(_compressionSession, kVTCompressionPropertyKey_AverageBitRate, bitrateBps);
+    SetVTSessionProperty(
+        _compressionSession, kVTCompressionPropertyKey_ExpectedFrameRate, frameRate);
 
     // TODO(tkchin): Add a helper method to set array value.
     int64_t dataLimitBytesPerSecondValue =
@@ -680,6 +684,7 @@ CFStringRef ExtractProfile(webrtc::SdpVideoFormat videoFormat) {
     }
 
     _encoderBitrateBps = bitrateBps;
+    _encoderFrameRate = frameRate;
   }
 }