I bought the apple sd card reader for the iPad2 however my ipad isn't reading the mp4 file on the sd card. What am I doing wrong?

The following gouge from MacWorld probably addresses your issues, as do numerous other threads in this and other forums and, well, for that matter, your Users Guide.

Video storage: One of the official features of the Camera Connection Kit is that it lets you import videos—presumably ones shot with your digital camera. If those videos are in H.264 format, you can then play them on the iPad. As Macworld contributor Jeff Carlson discovered, you can take advantage of this functionality and the SD-card adapter to use SD cards for storing video while traveling, thus freeing up room on your iPad for other content.

To perform such magic, you just convert your videos to iPad-compatible H.264 files (using, say,HandBrake), and then copy those videos to the DCIM folder on one or more SD cards. Plug the SD-card adapter into your iPad’s dock-connector port, insert an SD card, and the Photos app will automatically launch; your videos will appear as candidates for importing. (You must import a video to watch it—you can’t watch it from the SD card—which means you’ll want to keep enough free space on your iPad to accommodate your largest video. Once you’re done watching an imported video, you can delete it from the iPad to free up room for the next one.)

Importing video files using the Kit's SD-card adapter

Don’t look for these imported videos in the Videos app—since the iPad thinks you imported the videos from a digital camera, they appear in the Photos app. This means you don’t get all the viewing features of the Videos app, such as chapter navigation. The Photos app also doesn’t remember your playback position if you leave the app and come back later. Still, this is a great (unsupported) feature if your iPad is running out of storage space or if you want to bring along more movies than your iPad can hold.

I have a question about this too. Most of my movie collection is converted into h.264 format, but I also have quite a few that I have purchased off iTunes. Will those videos that I purchased off iTunes play via a SD card in the camera connection kit? Also, will any movies stored on a SD card play via the airplay feature as well? Say if I want to AirPlay those videos to an apple tv2?

You can't play anything directly off the SD card. It needs to be imported first.

On iOS 4 (I haven't tried it with iOS 5) I was able to copy an iTunes purchased film via the kit into the Photos app but it wouldn't play - a non-iTunes purchase played without problems.

Thanks Julian, but I gathered that much from the in depth answer Hcrous gave. My question implied, although due to lack of my not expressing my thoughts clearly enough.... So to say, more eloquently, can I import movies purchases off iTunes via the SD card? Or am I going to run into "protected" media and it won't play. As to my second question, will those "imported" movies play via AirPlay? Whether they be movies purchased off iTunes, or movies converted to h.264 format.

Thank you king penguin, for your answer, and for understanding my implied question.

I guess my question in return would be: What would be the reason for you wanting to transfer iTunes purchases to the SD card, then importing from there into the iPad, and then playing them with the limitations that exist in the Photos (only iOS 4 terminology used here) app, as opposed to doing the more normal syncing of the content directly from iTunes and then playing them in the Videos app with its fuller feature set?

The only only obvious reason would be if space on the iPad is limited. 64gb fills up fast when you have music, movies and photo's all vying for valuable space. Having the option of storing some of those movies on an SD card would be a nice convienience on a long road trip. Much cheaper than buying something like the goflex satalite wifi hard drive. Thus the reason for my question as to if iTunes purchases can be imported or if they would be prohibited to play via this method. You answered the question pertaining to h.264 formats, and I appologize that I gave credit to your detailed answer to the wrong person. And when you say that in Photo's (only iOS 4 terminology used here), are you saying that you could not stream a h.264 movie to say an apple tv2? Because I thought you could steam photo's at least to the apple tv2 via AirPlay. Clarification on this matter would be appreciated. Thank you

And I should add some clarification now......King penguin answered part of question already, and that was whether iTunes movies would play via this method. They don't, at least in ios 4. And I will assume ios 5 is the same.... So at this point the only reason I would put h.264 movies on an SD card would be to conserve the limited space on my iPad 2. Since in order to watch iTunes movies on the iPad they have be transferred there via iTunes because they are protected content, so the more of those types of movies I have stored on the iPad, the less "converted" h.264 movies I can have on there at the same time. So storing them on an SD card would be very handy. And like I said much cheaper than getting something like the seagate goflex satellite or some other type of similar device....... But as of yet no one has answered if those h.264 movies that are imported into the iPad photo app will be able to be played over AirPlay? Or even through mirroring on the iPad 2, to the apple tv 2...... Thank you for letting claifiy my question more in depth. Hopefully I explained it well enough. Thank you again, in advance....

And p.s

I contacted seagate to inquire if the goflex satellite will allow me to stream movies to the iPad and then if I could steam said movie to the apple tv 2 via AirPlay? The goflex satellite does not support AirPlay features.

To expand on what Michael Morgan1 said:

I'm in the same boat. I have a 16GB iPad that I'm taking on a long trip. I want to bring more movies that what'll fit. Using the SD card trick will work, but he omitted some important steps.

The movie files must be exactly eight chars long, ending with an acceptable format like mp4.

I'm still trying ti figure out how to arrangement on the SD card so you know what you are importing.

Worse, no subtitles unless they are burned-in. Why the **** can I not watch them in Videos? This is just typical Apple B.S. Reason # 437 of why I hate Apple as a company but love build quality of their products.

I am a newbie Ipad 2 user. Initially bought a galaxy tab 2, but went to the ipad. I realize I have to buy the accessory for the camera attachment and SD card reader, but I want to buy a movie off of amazon, save it to an SD card ( also to save space on my 16 GB ipad), and play it if on vacation...ect. One reason I tried the galaxy android tablet was it has an SD slot, and can upgrade the 16 GB to 32 so easily. I am a retiree, but used to teach computers to elementary kids, so a novice with a bit of background. Thx.