diff --git a/filter_context.go b/filter_context.go
index c911a40..6fe2248 100644
--- a/filter_context.go
+++ b/filter_context.go
@@ -39,3 +39,15 @@ func (fc *FilterContext) Free() {
 func (fc *FilterContext) Class() *Class {
 	return newClassFromC(unsafe.Pointer(fc.c))
 }
+
+// https://ffmpeg.org/doxygen/7.0/structAVFilterContext.html#addd946fbe5af506a2b19f9ad7cb97c35
+func (fc *FilterContext) SetHardwareDeviceContext(hdc *HardwareDeviceContext) {
+	if fc.c.hw_device_ctx != nil {
+		C.av_buffer_unref(&fc.c.hw_device_ctx)
+	}
+	if hdc != nil {
+		fc.c.hw_device_ctx = hdc.c
+	} else {
+		fc.c.hw_device_ctx = nil
+	}
+}
diff --git a/filter_graph.go b/filter_graph.go
index 46ec6a2..bd26739 100644
--- a/filter_graph.go
+++ b/filter_graph.go
@@ -4,6 +4,7 @@ package astiav
 import "C"
 import (
 	"errors"
+	"math"
 	"unsafe"
 )
 
@@ -154,3 +155,17 @@ func (g *FilterGraph) SendCommand(target, cmd, args string, f FilterCommandFlags
 	})
 	return
 }
+
+// https://ffmpeg.org/doxygen/7.0/structAVFilterGraph.html#a0ba5c820c760788ea5f8e40c476f9704
+func (g *FilterGraph) NbFilters() int {
+	return int(g.c.nb_filters)
+}
+
+// https://ffmpeg.org/doxygen/7.0/structAVFilterGraph.html#a1dafd3d239f7c2f5e3ac109578ef926d
+func (g *FilterGraph) Filters() (fs []*FilterContext) {
+	fcs := (*[(math.MaxInt32 - 1) / unsafe.Sizeof((*C.AVFilterContext)(nil))](*C.AVFilterContext))(unsafe.Pointer(g.c.filters))
+	for i := 0; i < g.NbFilters(); i++ {
+		fs = append(fs, newFilterContext(fcs[i]))
+	}
+	return
+}
diff --git a/filter_graph_test.go b/filter_graph_test.go
index 9e5d11d..0f1b533 100644
--- a/filter_graph_test.go
+++ b/filter_graph_test.go
@@ -247,6 +247,43 @@ func TestFilterGraph(t *testing.T) {
 	require.Equal(t, 1, len(os))
 	require.Equal(t, MediaTypeAudio, os[0].MediaType())
 
+	fg3 := AllocFilterGraph()
+	require.NotNil(t, fg3)
+	defer fg3.Free()
+	outputs := AllocFilterInOut()
+	br := FindFilterByName("buffer")
+	brCtx, err := fg3.NewBuffersrcFilterContext(br, "in")
+	require.NoError(t, err)
+	brCtxParameters := AllocBuffersrcFilterContextParameters()
+	brCtxParameters.SetPixelFormat(PixelFormatYuv420P)
+	brCtxParameters.SetSampleAspectRatio(NewRational(1, 1))
+	brCtxParameters.SetWidth(1080)
+	brCtxParameters.SetHeight(720)
+	brCtxParameters.SetTimeBase(NewRational(1, 30))
+	err = brCtx.SetParameters(brCtxParameters)
+	require.NoError(t, err)
+	err = brCtx.Initialize(nil)
+	require.NoError(t, err)
+	outputs.SetName("in")
+	outputs.SetFilterContext(brCtx.FilterContext())
+	outputs.SetPadIdx(0)
+	outputs.SetNext(nil)
+	inputs := AllocFilterInOut()
+	bs := FindFilterByName("buffersink")
+	bsCtx, err := fg3.NewBuffersinkFilterContext(bs, "out")
+	require.NoError(t, err)
+	inputs.SetName("out")
+	inputs.SetFilterContext(bsCtx.FilterContext())
+	inputs.SetPadIdx(0)
+	inputs.SetNext(nil)
+	err = fg3.Parse("movie=filename=testdata/video.mp4[mv];[in][mv]overlay=x=100:y=100[ol];[ol]scale=w=1080:h=720[out]", outputs, inputs)
+	require.NoError(t, err)
+	var filterNames string
+	for _, filterContext := range fg3.Filters() {
+		filterNames += fmt.Sprintf("[%s]", filterContext.Class().ItemName())
+	}
+	require.Equal(t, "[in][out][Parsed_movie_0][Parsed_overlay_1][Parsed_scale_2]", filterNames)
+
 	// TODO Test BuffersrcAddFrame
 	// TODO Test BuffersinkGetFrame
 }