There is this problem that I have with my 7 year old Panasonic Viera LCD TV - it just can't play certain MP4 movies. The video and audio CODECs (usually H264 for video and AAC for audio) are all compatible with what the TV supports, but it just won't play.
The problem, after much digging, is that this particular Panasonic TV model only supports playing video files that are in certain video standard resolution - 360p or 720p resolution, for example. It took me many attempts, but one workaround is to convert the video CODEC into XVID/DIVX. The size of the output file may be larger, but hey, it works.
I use ffmpeg to do the audio and video codec conversion. And this is the command that I use:
