+ // read again as multiple channels in an undersized matrix
+ del_fmat(mat);
+ mat = new_fmat(channels - 1, hop_size);
+ aubio_source_custom_do_multi(s, mat, &read);
+ if (read != hop_size) return 1;
+
+ // read again as multiple channels in an undersized matrix
+ del_fmat(mat);
+ mat = new_fmat(channels, hop_size - 1);
+ aubio_source_custom_do_multi(s, mat, &read);
+ if (read != hop_size - 1) return 1;
+
+ // read again as multiple channels in an oversized matrix
+ del_fmat(mat);
+ mat = new_fmat(channels + 1, hop_size);
+ aubio_source_custom_do_multi(s, mat, &read);
+ if (read != hop_size) return 1;
+
+ // read again as multiple channels in an oversized matrix
+ del_fmat(mat);
+ mat = new_fmat(channels, hop_size + 1);
+ aubio_source_custom_do_multi(s, mat, &read);
+ if (read != hop_size) return 1;
+