I'm trying to encode an mp4/h.264 video file with an mp3 audio channel. I'm tried encoding it with both Adobe Media Encoder and ffmpeg (using libmp3lame). I'm streaming the video files using ffmpeg to stream the file through Red5 as a live stream. When the Flex AIR clients play the stream (using the Spark VideoDisplay component), I hear a frequent sort of chirping sounding audio artifact. I've also tried playing these files directly from my harddrive in a simple AIR app using NetStream and the Video component. When I try this I don't hear any audio at all. In both tests if I use an FLV (On2 VP6) file with an mp3 channel it sounds fine. Unfortunately I need to use h.264 video.