I have an LD-26LG4000 TV, there is also an antenna in the room, and an amplifier. I set up channels by automatic search, all channels were found. However, the radio channels work efficiently, and all TV channels are without sound and picture.
First, perform an engineering check of your device. This can be done in the TV settings. The signal level of the channels must be 70% or more, and the signal quality is exclusively 100%. Based on your question, we can say that the set-top box catches the stream, but there are problems with unpacking it. Check with the manufacturer if your model supports the MPEG4 / AVC standard. If the standard is not supported, then you need to purchase additional. MPEG4 NEOTION module or buy an external digital TV receiver with a supported standard.