static filterVariantsBySpatialAudio_(variants, spatialAudio) {
    return variants.filter((variant) => {
      if (variant.audio && variant.audio.spatialAudio != spatialAudio) {
        return false;
      }
      return true;
    });
  }
Filters variants according to the given spatial audio config.

@param {!Array<shaka.extern.Variant>} variants
@param {boolean} spatialAudio
@private