From f21c58306ed73ffdffe79f1d7ee5f9144f1ed646 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Sun, 6 Feb 2022 16:57:23 -0600
Subject: [PATCH] Preserve stream aspect ratio even when host resolution
 changes

---
 Limelight/Stream/StreamManager.m        |  2 +-
 Limelight/Stream/VideoDecoderRenderer.h |  2 +-
 Limelight/Stream/VideoDecoderRenderer.m | 21 +++++++++++++++++----
 3 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/Limelight/Stream/StreamManager.m b/Limelight/Stream/StreamManager.m
index 6437862..6abb87a 100644
--- a/Limelight/Stream/StreamManager.m
+++ b/Limelight/Stream/StreamManager.m
@@ -100,7 +100,7 @@
     
     // Initializing the renderer must be done on the main thread
     dispatch_async(dispatch_get_main_queue(), ^{
-        VideoDecoderRenderer* renderer = [[VideoDecoderRenderer alloc] initWithView:self->_renderView callbacks:self->_callbacks];
+        VideoDecoderRenderer* renderer = [[VideoDecoderRenderer alloc] initWithView:self->_renderView callbacks:self->_callbacks streamAspectRatio:(float)self->_config.width / (float)self->_config.height];
         self->_connection = [[Connection alloc] initWithConfig:self->_config renderer:renderer connectionCallbacks:self->_callbacks];
         NSOperationQueue* opQueue = [[NSOperationQueue alloc] init];
         [opQueue addOperation:self->_connection];
diff --git a/Limelight/Stream/VideoDecoderRenderer.h b/Limelight/Stream/VideoDecoderRenderer.h
index 5a6fb4b..62f82de 100644
--- a/Limelight/Stream/VideoDecoderRenderer.h
+++ b/Limelight/Stream/VideoDecoderRenderer.h
@@ -12,7 +12,7 @@
 
 @interface VideoDecoderRenderer : NSObject
 
-- (id)initWithView:(UIView*)view callbacks:(id<ConnectionCallbacks>)callbacks;
+- (id)initWithView:(UIView*)view callbacks:(id<ConnectionCallbacks>)callbacks streamAspectRatio:(float)aspectRatio;
 
 - (void)setupWithVideoFormat:(int)videoFormat frameRate:(int)frameRate;
 - (void)start;
diff --git a/Limelight/Stream/VideoDecoderRenderer.m b/Limelight/Stream/VideoDecoderRenderer.m
index bc553ac..7bccbdd 100644
--- a/Limelight/Stream/VideoDecoderRenderer.m
+++ b/Limelight/Stream/VideoDecoderRenderer.m
@@ -14,6 +14,7 @@
 @implementation VideoDecoderRenderer {
     StreamView* _view;
     id<ConnectionCallbacks> _callbacks;
+    float _streamAspectRatio;
     
     AVSampleBufferDisplayLayer* displayLayer;
     Boolean waitingForSps, waitingForPps, waitingForVps;
@@ -31,12 +32,23 @@
     CALayer *oldLayer = displayLayer;
     
     displayLayer = [[AVSampleBufferDisplayLayer alloc] init];
-    displayLayer.bounds = _view.bounds;
     displayLayer.backgroundColor = [UIColor blackColor].CGColor;
     
+    // Ensure the AVSampleBufferDisplayLayer is sized to preserve the aspect ratio
+    // of the video stream. We used to use AVLayerVideoGravityResizeAspect, but that
+    // respects the PAR encoded in the SPS which causes our computed video-relative
+    // touch location to be wrong in StreamView if the aspect ratio of the host
+    // desktop doesn't match the aspect ratio of the stream.
+    CGSize videoSize;
+    if (_view.bounds.size.width > _view.bounds.size.height * _streamAspectRatio) {
+        videoSize = CGSizeMake(_view.bounds.size.height * _streamAspectRatio, _view.bounds.size.height);
+    } else {
+        videoSize = CGSizeMake(_view.bounds.size.width, _view.bounds.size.width / _streamAspectRatio);
+    }
     displayLayer.position = CGPointMake(CGRectGetMidX(_view.bounds), CGRectGetMidY(_view.bounds));
-    displayLayer.videoGravity = AVLayerVideoGravityResizeAspect;
-    
+    displayLayer.bounds = CGRectMake(0, 0, videoSize.width, videoSize.height);
+    displayLayer.videoGravity = AVLayerVideoGravityResize;
+
     // Hide the layer until we get an IDR frame. This ensures we
     // can see the loading progress label as the stream is starting.
     displayLayer.hidden = YES;
@@ -63,12 +75,13 @@
     }
 }
 
-- (id)initWithView:(StreamView*)view callbacks:(id<ConnectionCallbacks>)callbacks
+- (id)initWithView:(StreamView*)view callbacks:(id<ConnectionCallbacks>)callbacks streamAspectRatio:(float)aspectRatio
 {
     self = [super init];
     
     _view = view;
     _callbacks = callbacks;
+    _streamAspectRatio = aspectRatio;
     
     [self reinitializeDisplayLayer];