R_Nick is right, PS3 will not play all AVI files as and AVI file is simply a container/wrapper (think file structure here not what format the data inside is in), it doesn't specify the codecs underneath. PCs are great in this respect as you just install new codecs/containers or update the codecs/containers, it's easy. Not so with fixed hardware. Even when the codec is known, it doesn't always work. An example would be when you use get_iplayer. It downloads the streams as FLVs and then converts them into MP4 video which the PS3 should be able to handle, and yes, the video is perfect, but the audio is all over the show, if there at all, yet on the PC they play perfectly. What's happening? Well, the audio encoder is obviously not sticking strictly to the standards and the PS3 gets confused, so you have to re-mux the file to create another MP4, and then it works on the PS3.