playback not available

Hi.
I have some problem in understanding the principles of DLNA protocol. I have a Sony S9005B series tv. There are some video formats that are not playable on tv. I get "playback not available". I have tried different configurations with no success. I have also tried to play the video directly on tv by putting it on usb disk and plug it directly into the tv. The video was played and srt subtitles showed up. Now I am confused. At first I thought the "generic profile" would do the job as there is no transcoding and the video would play as it was played directly from usb disk. But no luck. Same error "playback not available" is showing up.
Can anybody explain me what I am missing here? Thanks in advance.
I have some problem in understanding the principles of DLNA protocol. I have a Sony S9005B series tv. There are some video formats that are not playable on tv. I get "playback not available". I have tried different configurations with no success. I have also tried to play the video directly on tv by putting it on usb disk and plug it directly into the tv. The video was played and srt subtitles showed up. Now I am confused. At first I thought the "generic profile" would do the job as there is no transcoding and the video would play as it was played directly from usb disk. But no luck. Same error "playback not available" is showing up.
Can anybody explain me what I am missing here? Thanks in advance.