MPEG2 vs. MPEG4
The Moving Pictures Experts Group, or MPEG, is the body responsible for the standards that we often use for video encoding. MPEG2 is the standard that was created to encode high quality videos, meant to be used for the, then emerging, DVD media. MPEG4 was developed much later, as an encoding method for devices with limited resources. Portable devices, like media players and mobile phones, use this format, as well as online stores who provide the hiring of video and audio files.
MPEG4 is the preferred format for devices, as it yields a file that is under 1G for most full length movies. This is a far cry from MPEG2, which can only produce files with five times the size. Storing MPEG2 files will not be a problem on DVDs, as the usual DVD capacity is over 4GB, but is a major issue with portable devices. MPEG4 also made it practical to buy and download videos online, as MPEG2 videos are quite large, and take a long time to download. The small file size of MPEG4 files directly translates to a lower bandwidth needed, when streaming recorded or real-time videos through the internet.
Setting file size aside when considering the better format, MPEG2 wins hands-down, as it provides a far superior image quality. The difference in quality is minor when viewing the files through a tiny screen, like those installed in mobile phones and even netbooks, but when it comes to large displays, like most current HDTV displays, you can clearly notice the difference in the final picture. We can attribute this to the amount of data lost, since both MPEG2 and MPEG4 are compression methods that lose data. MPEG4 simply discards more information, which results in poorer picture.
MPEG2 compresses the video by discarding the information in portions of the image that do not change from one frame to another, and saving only the portions of the image where new information is added. The MPEG4 compression mechanism is a bit more complicated compared to that of MPEG2, as it needs better algorithms to scan and determine which pixels can be discarded, to reduce the data even further.
Summary:
1. MPEG2 is the encoding method for DVDs, while MPEG4 is the encoding method of choice for portable devices and online use.
2. MPEG2 encoded video files are much bigger compared to MPEG4.
3. MPEG2 requires a lot more bandwidth for streaming compared to MPEG4.
4. MPEG2 produces the best video quality compared to MPEG4.
5. MPEG2’s compression is much simpler compared to MPEG4.