retain buffers while decoders alive

avcodec.go

@@ -21,6 +21,7 @@ import (
 type avCodecDecoder struct {
 	decoder    C.avcodec_decoder
 	mat        C.opencv_mat
+	buf        []byte
 	hasDecoded bool
 	maybeMP4   bool
 }
@@ -41,6 +42,7 @@ func newAVCodecDecoder(buf []byte) (*avCodecDecoder, error) {
 	return &avCodecDecoder{
 		decoder:  decoder,
 		mat:      mat,
+		buf:      buf,
 		maybeMP4: isMP4(buf),
 	}, nil
 }
@@ -93,6 +95,7 @@ func (d *avCodecDecoder) DecodeTo(f *Framebuffer) error {
 func (d *avCodecDecoder) Close() {
 	C.avcodec_decoder_release(d.decoder)
 	C.opencv_mat_release(d.mat)
+	d.buf = nil
 }
 
 func init() {

giflib.go

@@ -23,6 +23,7 @@ import (
 type gifDecoder struct {
 	decoder    C.giflib_decoder
 	mat        C.opencv_mat
+	buf        []byte
 	frameIndex int
 }
 
@@ -64,6 +65,7 @@ func newGifDecoder(buf []byte) (*gifDecoder, error) {
 	return &gifDecoder{
 		decoder:    decoder,
 		mat:        mat,
+		buf:        buf,
 		frameIndex: 0,
 	}, nil
 }
@@ -91,6 +93,7 @@ func (d *gifDecoder) FrameHeader() (*ImageHeader, error) {
 func (d *gifDecoder) Close() {
 	C.giflib_decoder_release(d.decoder)
 	C.opencv_mat_release(d.mat)
+	d.buf = nil
 }
 
 func (d *gifDecoder) Description() string {

opencv.go

@@ -62,6 +62,7 @@ type Framebuffer struct {
 type openCVDecoder struct {
 	decoder       C.opencv_decoder
 	mat           C.opencv_mat
+	buf           []byte
 	hasReadHeader bool
 	hasDecoded    bool
 }
@@ -250,6 +251,7 @@ func newOpenCVDecoder(buf []byte) (*openCVDecoder, error) {
 	return &openCVDecoder{
 		mat:     mat,
 		decoder: decoder,
+		buf:     buf,
 	}, nil
 }
 
@@ -274,6 +276,7 @@ func (d *openCVDecoder) Header() (*ImageHeader, error) {
 func (d *openCVDecoder) Close() {
 	C.opencv_decoder_release(d.decoder)
 	C.opencv_mat_release(d.mat)
+	d.buf = nil
 }
 
 func (d *openCVDecoder) Description() string {