Тут проблема подробно описана:
Is the audio playing without the video or is nothing playing at all? VLC can play almost anything, but car receivers require specific formats. From what I can tell, the video files must use the DivX codec, and the format of the container file must be .avi or .divx, and the audio encoding must be MP2, MP3, or Dolby Digital. Youtube uses .flv and .mp4, so any video you download from youtube will need to be converted. The .avi file format is considered a "container" format because it can contain video and audio of different codecs. For example, an .avi file that was encoded with mpeg video and aac audio would still need to be converted in order to play properly. There are many free video converters available, try converting some videos to divx video/mp3 audio and see if that works better. Let me know if you have any other questions.