diff --git a/libavformat/rka.c b/libavformat/rka.c
index cc55480345..39e5b3bce1 100644
--- a/libavformat/rka.c
+++ b/libavformat/rka.c
@@ -114,7 +114,7 @@ static int rka_read_header(AVFormatContext *s)
     par->ch_layout.nb_channels = channels;
     par->sample_rate = samplerate;
     par->bits_per_raw_sample = bps;
-    st->duration = nb_samples / (channels * (bps >> 3));
+    st->duration = 8LL*nb_samples / (channels * bps);
 
     if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
         ff_ape_parse_tag(s);