MARDI Images are freely available from NASA's website:
The MARDI (Mars Descent Imager) camera on Curiosity filmed the entire descent sequence at about 4 frames per second, at a resolution of 1648x1200. About 1400 images were taken, but only really 700 of these show the descent and landing; the rest are just pictures of the ground immediately underneath the rover, after landing. Presumably the camera was programmed to keep running in case something bad happened, which it didn't.
All of these images need to be downloaded from the rover to Earth, which takes some time. The images are around 130-160 kilobytes each, so that's about 98 megabytes of data to download, and the rover has other things that it's doing and other images to transmit.
As of the time I made this video, only 44 images from the first 700 showing the descent were missing. Since all of the thumbnail images (I think 160x140 pixels or something like that) are already available here on earth, I have filled in those 44 images with thumbnails that are upscaled. This is why the image seems to "blink" or shift to low-resolution periodically, and why the very end shows it on the ground. The last few seconds on the ground are also all low-resolution, all told this video is in HD except for about 64 images.
We can tell which frames are missing based on the sequence numbers of the frames. The fourth image is named for instance "0000MD9999000004E1_DXXX.jpg", the "4" before the "E1_DXXX" being the frame number. So we just have to combine this knowledge with the fact that MARDI films in 4 frames per second to reconstruct the descent in real time.
The audio was taken from the ustream.tv recording of the landing event:
I started this video at about 25:42 in the above recording, this is already well-into the descent but for most of that the heat shield was on so there's really nothing to see (MARDI does not start filming until just before the heat shield is jettisoned.)
I did a little bit of compression (dynamic range compression) get the levels the same but no changes in timing.
I am sure that NASA will release an official video but I just couldn't wait! =) In fact I made the first video last week but there were still many frames missing and I didn't think to sync the control room audio.
It should be possible to do some excellent interpolation between frames to bump this up to an "actual" 60fps, which is a project I might endeavor to take on, in case nobody else does. But if anybody wants the source images or audio that I used to do this themselves, please just drop me a line and I'll hook you up!