diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c
index 1bb71f5a47..8c4ff53617 100644
--- a/libavcodec/alsdec.c
+++ b/libavcodec/alsdec.c
@@ -1527,7 +1527,7 @@ static int read_diff_float_data(ALSDecContext *ctx, unsigned int ra_frame) {
             if (!get_bits1(gb)) { //uncompressed
                 for (i = 0; i < frame_length; ++i) {
                     if (ctx->raw_samples[c][i] != 0) {
-                        raw_mantissa[c][i] = get_bits(gb, nbits[i]);
+                        raw_mantissa[c][i] = nbits[i] ? get_bits(gb, nbits[i]) : 0;
                     }
                 }
             } else { //compressed