Video formats for mobile devices
A natural and logical stage in the development of mobile communications is the ability to stream and view videos on mobile phones.
Currently, almost all mobile devices are equipped with built-in cameras with the ability to record and play video files. The video format used in this case is based on the MP4 / 3gp protocol, but this does not at all mean that modern phones cannot understand other formats for presenting video data. Videos take up much more space than audio files or images. This leads to the fact that the video has to be highly compressed.
Mobile video generally has the following resolutions:
640 × 360
320 x 240
176×144
Also, many modern devices have the ability to record and play back Full HD format.
Examples of video formats for mobile devices:
MP4
It is an abbreviation for MPEG-4 Part 14. This format may also be called MPEG-4 AVC, where AVC stands for Advanced Video Coding. As the name of the format suggests, it is designed to work with video files and was first proposed in 1998. MP4 is a container format that allows you to combine audio, video, subtitles, and images into a single file. Video files of this standard have the extensions * .mp4 and * .3gp. All players capable of playing MP4 can play 3GPP and vice versa.
3GP
* .3GP (3GPP file format) is a multimedia container defined by the Third Generation Partnership Project (3GPP) for 3G UMTS multimedia services. Many modern mobile phones (not necessarily 3G) have the capabilities of recording and viewing audio and video in .3GP format.
This format is a simplified version of the ISO 14496-1 multimedia format, which is similar to the MOV used by QuickTime. Video clips ending in 3GP are small compared to similar videos in other formats, however this is justified by the low quality, for example many frames are often presented as colored squares. 3GP is a special case of MP4 video. This standard has been used relatively recently, thanks to Philips, which has gone to great lengths to adapt the MPEG-4 standard for transmission.
The 3GPP standard has become the leading standard in camera phones with video recording capabilities. Initially, it was the staple on SonyEricsson smartphones; PacketVideo – PVPlayer even developed special viewing software for them, which allows you to play video in full screen. Currently, this player is available for almost all smartphones based on Symbian and Windows Mobile operating systems, as well as for PocketPC PDAs.
The advantages of the format include the fact that if the original image size does not match, it is automatically converted to the size supported by the phone. However, the quality of the videos is very low. Initially, this format was intended for the rapid recording of video material using the built-in camera, for later viewing and sending as an attachment in MMS (limited to 100 Kb).
The low video quality is due to the low resolution of the image, which can be QCIF (176 × 144) or sub-QCIF (128 × 96), the low frame rate, no more than 15 per second, and the peculiarities sound recording. The sound that accompanies the video clip can be recorded in AMR (12.2 kbps maximum stream) or WB AMR (23.05 kbps stream) format.
Other formats
There is also the classic MobiClip-MPEG-1 video format. In October 2003, MobiClip introduced a very interesting format. The format is inherently universal. Files converted to this format have the * .mo extension and can contain sound, video, and flash animation. On the manufacturer’s website, this format is advertised as full-screen mobile video without brakes. Its essential limitation is its non-transmission nature, that is, to view it it is necessary to download the complete file. Another limitation, not fundamental, but significant, of the format is the large size of the files received. Thus, a video format appeared on phones, capable of providing high image quality at almost cinematic frame rate. The quality of the playback depends solely on the amount of memory available. The video plays in full screen.
Modern smartphones have a wider range of playable video formats. In addition to the above, smartphones can read * .rm files, the quality of which is superior to both 3gp and mp4, as well as the * .avi format, after installing the appropriate programs (eg SmartMovie).
