Allow NV12 and NV21 to be selected for non-hwaccel decoders using the SDL renderer

app/streaming/video/ffmpeg-renderers/renderer.h

@@ -62,6 +62,11 @@ public:
         }
     }
 
+    virtual bool isPixelFormatSupported(int videoFormat, enum AVPixelFormat pixelFormat) {
+        // By default, we only support the preferred pixel format
+        return getPreferredPixelFormat(videoFormat) == pixelFormat;
+    }
+
     // IOverlayRenderer
     virtual void notifyOverlayUpdated(Overlay::OverlayType) override {
         // Nothing

app/streaming/video/ffmpeg-renderers/sdlvid.cpp

@@ -127,6 +127,21 @@ bool SdlRenderer::isRenderThreadSupported()
     return true;
 }
 
+bool SdlRenderer::isPixelFormatSupported(int, AVPixelFormat pixelFormat)
+{
+    // Remember to keep this in sync with SdlRenderer::renderFrame()!
+    switch (pixelFormat)
+    {
+    case AV_PIX_FMT_YUV420P:
+    case AV_PIX_FMT_NV12:
+    case AV_PIX_FMT_NV21:
+        return true;
+
+    default:
+        return false;
+    }
+}
+
 bool SdlRenderer::initialize(PDECODER_PARAMETERS params)
 {
     Uint32 rendererFlags = SDL_RENDERER_ACCELERATED;
@@ -271,6 +286,7 @@ void SdlRenderer::renderFrame(AVFrame* frame)
     if (m_Texture == nullptr) {
         Uint32 sdlFormat;
 
+        // Remember to keep this in sync with SdlRenderer::isPixelFormatSupported()!
         switch (frame->format)
         {
         case AV_PIX_FMT_YUV420P:

app/streaming/video/ffmpeg-renderers/sdlvid.h

@@ -13,6 +13,7 @@ public:
     virtual void renderFrame(AVFrame* frame) override;
     virtual void notifyOverlayUpdated(Overlay::OverlayType) override;
     virtual bool isRenderThreadSupported() override;
+    virtual bool isPixelFormatSupported(int videoFormat, enum AVPixelFormat pixelFormat) override;
 
 private:
     void renderOverlay(Overlay::OverlayType type);

app/streaming/video/ffmpeg.cpp

@@ -73,7 +73,7 @@ enum AVPixelFormat FFmpegVideoDecoder::ffGetFormat(AVCodecContext* context,
     const enum AVPixelFormat *p;
 
     for (p = pixFmts; *p != -1; p++) {
-        // Only match our hardware decoding codec or SW pixel
+        // Only match our hardware decoding codec or preferred SW pixel
         // format (if not using hardware decoding). It's crucial
         // to override the default get_format() which will try
         // to gracefully fall back to software decode and break us.
@@ -84,6 +84,15 @@ enum AVPixelFormat FFmpegVideoDecoder::ffGetFormat(AVCodecContext* context,
         }
     }
 
+    // Failed to match the preferred pixel formats. Try non-preferred options for non-hwaccel decoders.
+    if (decoder->m_HwDecodeCfg == nullptr) {
+        for (p = pixFmts; *p != -1; p++) {
+            if (decoder->m_FrontendRenderer->isPixelFormatSupported(decoder->m_VideoFormat, *p)) {
+                return *p;
+            }
+        }
+    }
+
     return AV_PIX_FMT_NONE;
 }
 
@@ -97,6 +106,7 @@ FFmpegVideoDecoder::FFmpegVideoDecoder(bool testOnly)
       m_Pacer(nullptr),
       m_LastFrameNumber(0),
       m_StreamFps(0),
+      m_VideoFormat(0),
       m_NeedsSpsFixup(false),
       m_TestOnly(testOnly)
 {
@@ -206,6 +216,7 @@ bool FFmpegVideoDecoder::completeInitialization(AVCodec* decoder, PDECODER_PARAM
     }
 
     m_StreamFps = params->frameRate;
+    m_VideoFormat = params->videoFormat;
 
     // Don't bother initializing Pacer if we're not actually going to render
     if (!testFrame) {

app/streaming/video/ffmpeg.h

@@ -63,6 +63,7 @@ private:
 
     int m_LastFrameNumber;
     int m_StreamFps;
+    int m_VideoFormat;
     bool m_NeedsSpsFixup;
     bool m_TestOnly;