From b6bb96223d744c2baddb7790f2a5f1b587640450 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Sat, 22 Jun 2024 12:34:10 -0500
Subject: [PATCH] Revert "Remove manual hwframe ctx setup for D3D11VA"

We need this back to avoid the copy that's tanking performance on Intel iGPUs.

This reverts commit 2cef09471b80d46ea3b59a936494a44a68ad5d67.
---
 .../video/ffmpeg-renderers/d3d11va.cpp        | 59 +++++++++++++++++--
 .../video/ffmpeg-renderers/d3d11va.h          |  3 +
 2 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/app/streaming/video/ffmpeg-renderers/d3d11va.cpp b/app/streaming/video/ffmpeg-renderers/d3d11va.cpp
index 66364532..50cf15e9 100644
--- a/app/streaming/video/ffmpeg-renderers/d3d11va.cpp
+++ b/app/streaming/video/ffmpeg-renderers/d3d11va.cpp
@@ -93,7 +93,8 @@ D3D11VARenderer::D3D11VARenderer(int decoderSelectionPass)
       m_VideoTexture(nullptr),
       m_OverlayLock(0),
       m_OverlayPixelShader(nullptr),
-      m_HwDeviceContext(nullptr)
+      m_HwDeviceContext(nullptr),
+      m_HwFramesContext(nullptr)
 {
     RtlZeroMemory(m_OverlayVertexBuffers, sizeof(m_OverlayVertexBuffers));
     RtlZeroMemory(m_OverlayTextures, sizeof(m_OverlayTextures));
@@ -139,6 +140,10 @@ D3D11VARenderer::~D3D11VARenderer()
     SAFE_COM_RELEASE(m_RenderTargetView);
     SAFE_COM_RELEASE(m_SwapChain);
 
+    if (m_HwFramesContext != nullptr) {
+        av_buffer_unref(&m_HwFramesContext);
+    }
+
     // Force destruction of the swapchain immediately
     if (m_DeviceContext != nullptr) {
         m_DeviceContext->ClearState();
@@ -429,6 +434,10 @@ bool D3D11VARenderer::initialize(PDECODER_PARAMETERS params)
         return false;
     }
 
+    // Surfaces must be 16 pixel aligned for H.264 and 128 pixel aligned for everything else
+    // https://github.com/FFmpeg/FFmpeg/blob/a234e5cd80224c95a205c1f3e297d8c04a1374c3/libavcodec/dxva2.c#L609-L616
+    m_TextureAlignment = (params->videoFormat & VIDEO_FORMAT_MASK_H264) ? 16 : 128;
+
     if (!setupRenderingResources()) {
         return false;
     }
@@ -462,9 +471,43 @@ bool D3D11VARenderer::initialize(PDECODER_PARAMETERS params)
         }
     }
 
-    // Create our video texture and SRVs
-    if (!setupVideoTexture()) {
-        return false;
+    {
+        m_HwFramesContext = av_hwframe_ctx_alloc(m_HwDeviceContext);
+        if (!m_HwFramesContext) {
+            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                        "Failed to allocate D3D11VA frame context");
+            return false;
+        }
+
+        AVHWFramesContext* framesContext = (AVHWFramesContext*)m_HwFramesContext->data;
+
+        // We require NV12 or P010 textures for our shader
+        framesContext->format = AV_PIX_FMT_D3D11;
+        framesContext->sw_format = (params->videoFormat & VIDEO_FORMAT_MASK_10BIT) ?
+                    AV_PIX_FMT_P010 : AV_PIX_FMT_NV12;
+
+        framesContext->width = FFALIGN(params->width, m_TextureAlignment);
+        framesContext->height = FFALIGN(params->height, m_TextureAlignment);
+
+        // We can have up to 16 reference frames plus a working surface
+        framesContext->initial_pool_size = 17;
+
+        AVD3D11VAFramesContext* d3d11vaFramesContext = (AVD3D11VAFramesContext*)framesContext->hwctx;
+
+        d3d11vaFramesContext->BindFlags = D3D11_BIND_DECODER;
+
+        int err = av_hwframe_ctx_init(m_HwFramesContext);
+        if (err < 0) {
+            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                         "Failed to initialize D3D11VA frame context: %d",
+                         err);
+            return false;
+        }
+
+        // Create our video texture and SRVs
+        if (!setupVideoTexture()) {
+            return false;
+        }
     }
 
     return true;
@@ -480,6 +523,14 @@ bool D3D11VARenderer::prepareDecoderContext(AVCodecContext* context, AVDictionar
     return true;
 }
 
+bool D3D11VARenderer::prepareDecoderContextInGetFormat(AVCodecContext *context, AVPixelFormat)
+{
+    // hw_frames_ctx must be initialized in ffGetFormat().
+    context->hw_frames_ctx = av_buffer_ref(m_HwFramesContext);
+
+    return true;
+}
+
 void D3D11VARenderer::renderFrame(AVFrame* frame)
 {
     // Acquire the context lock for rendering to prevent concurrent
diff --git a/app/streaming/video/ffmpeg-renderers/d3d11va.h b/app/streaming/video/ffmpeg-renderers/d3d11va.h
index 88aa86fc..6434a5c2 100644
--- a/app/streaming/video/ffmpeg-renderers/d3d11va.h
+++ b/app/streaming/video/ffmpeg-renderers/d3d11va.h
@@ -16,6 +16,7 @@ public:
     virtual ~D3D11VARenderer() override;
     virtual bool initialize(PDECODER_PARAMETERS params) override;
     virtual bool prepareDecoderContext(AVCodecContext* context, AVDictionary**) override;
+    virtual bool prepareDecoderContextInGetFormat(AVCodecContext* context, AVPixelFormat pixelFormat) override;
     virtual void renderFrame(AVFrame* frame) override;
     virtual void notifyOverlayUpdated(Overlay::OverlayType) override;
     virtual int getRendererAttributes() override;
@@ -47,6 +48,7 @@ private:
     SDL_mutex* m_ContextLock;
 
     DECODER_PARAMETERS m_DecoderParams;
+    int m_TextureAlignment;
     int m_DisplayWidth;
     int m_DisplayHeight;
     int m_LastColorSpace;
@@ -70,5 +72,6 @@ private:
     ID3D11PixelShader* m_OverlayPixelShader;
 
     AVBufferRef* m_HwDeviceContext;
+    AVBufferRef* m_HwFramesContext;
 };