Fixed hardware filtering example

examples/hardware_decoding_filtering/main.go

@@ -228,7 +228,7 @@ func main() {
 
 					// Make sure the filter is initialized
 					// We need to wait for the first frame to be decoded before initializing the filter
-					// since the decoder codec context doesn't have a valid hardware frame context until then
+					// since we need a valid hardware frames context
 					if filterGraph == nil {
 						if err := initFilter(); err != nil {
 							log.Fatal(fmt.Errorf("main: initializing filter failed: %w", err))
@@ -305,7 +305,7 @@ func initFilter() (err error) {
 	// Create buffersrc context parameters
 	buffersrcContextParameters := astiav.AllocBuffersrcFilterContextParameters()
 	defer buffersrcContextParameters.Free()
-	buffersrcContextParameters.SetHardwareFramesContext(decCodecContext.HardwareFramesContext())
+	buffersrcContextParameters.SetHardwareFramesContext(decodedHardwareFrame.HardwareFramesContext())
 	buffersrcContextParameters.SetHeight(decCodecContext.Height())
 	buffersrcContextParameters.SetPixelFormat(decCodecContext.PixelFormat())
 	buffersrcContextParameters.SetSampleAspectRatio(decCodecContext.SampleAspectRatio())

frame.go

@@ -87,6 +87,11 @@ func (f *Frame) Data() *FrameData {
 	return newFrameData(newFrameDataFrame(f))
 }
 
+// https://ffmpeg.org/doxygen/7.0/structAVFrame.html#a29493fbfabaa21432c360a090426aa8e
+func (f *Frame) HardwareFramesContext() *HardwareFramesContext {
+	return newHardwareFramesContextFromC(f.c.hw_frames_ctx)
+}
+
 // https://ffmpeg.org/doxygen/7.0/structAVFrame.html#a3f89733f429c98ba5bc64373fb0a3f13
 func (f *Frame) Height() int {
 	return int(f.c.height)