diff --git a/src/lib/ffmpeg/Interleave.cxx b/src/lib/ffmpeg/Interleave.cxx
index 51378b53b..4e901315f 100644
--- a/src/lib/ffmpeg/Interleave.cxx
+++ b/src/lib/ffmpeg/Interleave.cxx
@@ -37,7 +37,7 @@ InterleaveFrame(const AVFrame &frame, FfmpegBuffer &buffer)
 {
 	assert(frame.nb_samples > 0);
 
-	const AVSampleFormat format = AVSampleFormat(frame.format);
+	const auto format = AVSampleFormat(frame.format);
 	const unsigned channels = frame.channels;
 	const std::size_t n_frames = frame.nb_samples;