The term "1080p24" denotes film material or signals with 1080 lines and 24 full frames per second. The support of such signals has become an important feature of modern flat screens and is now relatively common amongst modern FullHD models.
Where do you find 1080p24 material?
Film is generally saved to the new HD media, that is Blu-ray and HD-DVD, in 1080p24 format. The PAL speed-up that generally arises with PAL material does not occur. This was used until now to adjust film (which is usually recorded at 24 frames per second) to the usual frequency of 50Hz. In the ideal scenario, the player can play back the material exactly as it is recorded – in this case, at the original 24 frames per second. Optionally, playback at 60 half or full frames per second is always possible. Since a non-linear divisional scheme is present (see 3:2 pulldown), however, this signal is no longer judder-free without very intensive adjustment. However, it is possible to play the material back on a flat screen that does not support 1080p24 signals.
1080p24 is not immediately 1080p24?
If the flat screen processes a relevant signal, this is not a guarantee that the playback will be judder-free. The full frames being played back must be passed on to the panel in a linear fashion. As long as this is happening (e.g. double display of every full frame so that a frequency of 48Hz arises), the original impression of movement is retained. Unfortunately, it is common to encounter solutions where the material is converted to an "unsuitable" frequency (e.g. 60Hz). The reason is that there are limitations on the electronic side. This means that in such cases, as with 60Hz-Ausgabe via the player, additional juddering is caused. If in doubt, you should inform yourself thoroughly about the extent of the functionality on your intended screen.
No juddering guaranteed?
The timely resolution of film with its 24 full frames per second is not always sufficient to allow for judder-free playback. However, this is nothing new, since it is connected with characteristics of the material being played back. The cinema (and even the good old cathode ray television) cannot offer a more fluid impression of movement. PAL speed-up changes nothing in this situation. Artificial increasing of the resolution is possible with the implementation of inter-frame calculation, but the material is visibly altered as a result ("Video look").