diff --git a/src/ffmpeg/avcodec.cpp b/src/ffmpeg/avcodec.cpp
index b2e32ac..f1d4fdf 100644
--- a/src/ffmpeg/avcodec.cpp
+++ b/src/ffmpeg/avcodec.cpp
@@ -27,9 +27,7 @@ Decoder AVCodec::make_decoder (unsigned int width, unsigned int height, ::AVPixe
 
 	context->width = width;
 	context->height = height;
-
-	if (::avcodec_open2(context.get(), codec, nullptr) < 0)
-		throw std::runtime_error("Could not open codec");
+	context->codec = codec;
 
 	return {std::move(context), dst_format};
 }
diff --git a/src/ffmpeg/decoder.cpp b/src/ffmpeg/decoder.cpp
index 65378b9..288bd72 100644
--- a/src/ffmpeg/decoder.cpp
+++ b/src/ffmpeg/decoder.cpp
@@ -36,8 +36,12 @@ Decoder::Decoder (UniqueAVCodecContext&& context, ::AVPixelFormat dst_format) :
 	m_dst_format(dst_format)
 {
 	assert(not m_context->opaque);
+	assert(m_context->codec);
 	m_context->opaque = this;
 	m_context->get_format = &get_favourite_format_ifp;
+
+	if (::avcodec_open2(m_context.get(), m_context->codec, nullptr) < 0)
+		throw std::runtime_error("Could not open codec");
 }
 
 Decoder::~Decoder() noexcept = default;