iMovie+Sizes

When you export your movie, iMovie gives you four size options:


 * **Tiny:** Always 176 by 144 pixels.
 * **Mobile:** Always 480 by 272 pixels.
 * **Medium:** Varies in size from 640 by 480 pixels (standard aspect ratio) to 640 by 360 pixels (widescreen), depending on the size of the media in your project.
 * **Large:** Always 960 by 540 pixels (widescreen). No large size is rendered if your original video isn’t high definition (HD).

If the larger sizes are not available, the original project media isn’t large enough to render in that size. The largest media size used in the project determines the final movie sizes you can render.

The dots below each device in the table of sizes indicate which movie sizes are recommended for use with that device. Hovering the pointer over the “i” next to the movie dimensions displays the following information for the rendered movies:


 * **H.264:** The standard video compression that's used in the movie.
 * **fps:** The frame rate of the movie in frames per second.
 * **Kbps:** The maximum rate at which the movie can be streamed over the Internet in kilobytes per second.
 * **MB:** The size of the movie file in megabytes.

How does MPEG-2 compare to H.264? HD MPEG-2 content at 1920x1080 traditionally runs at 12-20 Mbps, while H.264 can deliver 1920x1080 content at 7-8 Mbps at the same or better quality. H.264 provides DVD quality at about half the data rate of MPEG-2. Because of this efficiency, H.264, an ISO standard, stands to be the likely successor to MPEG-2 in the professional media industry.

(Video compression is a process which reduces the number of bytes required to store/transmit digital video.)
 * Video compression types:**
 * **MPEG 4** - most common video compression type
 * **DivX** - variation of MPEG 4
 * **Xvid** - freeware variation of MPEG 4
 * **Windows Media** - compressed video file format for several proprietary codecs developed by Microsoft
 * **H264** - the most advanced implementaion of MPEG4 standard
 * **MPEG 2 Program Stream (VOB)** - Used by DVD
 * **MPEG 2 Transport Stream** - Used by Blu-ray and Digital TV sources
 * **MPEG 1** - mostly used by VCD
 * **Motion JPEG**- used by digital cameras, surveillance systems and other portable devices
 * **DV** - used by DV-tape camcoders and cameras
 * **H263** - used for videoconferencing and flash video content
 * **VC1** - used for HD DVDs, Blu-ray Discs, and Windows Media Video 9.
 * **Indeo 3** - used for the compression of television-quality video
 * **Huffyuv** - a lossless video codec
 * **Smacker** - used in computer games, supports only 256 colors and includes transparency support.
 * and others