Tvheadend

in the NIT table there can be a Logical Channel Descriptor present. This descriptor has DVB descriptor tag 0x83. The syntax for this descriptor is as follows:

logical_channel_descriptor(){
descriptor_tag                  8 uimsbf
descriptor_length               8 uimsbf
     for (i=0; i<N;i++){
     service_id                16 uimsbf
     visible_service_flag       1 bslbf
     reserved                   5 bslbf
     logical_channel_number    10 uimsbf
     }
}

This descriptor gives the logical channel number for a service. This number could be used by TV Headend to populate the Channel Number based on this number.