MP4 files (MPEG-4 Part 14) are multimedia files. MP4 is a container format that can store video, audio and subtitle data (as well as more depending on content). Since stores like iTunes uses this container format, and it is used with iPod and PlayStation Portable (PSP), MP4 files have become more common.
MPEG-4 Part 14 or MP4, formally ISO/IEC 14496-14:2003, is a multimedia container format standard specified as a part of MPEG-4. It is most commonly used to store digital video and digital audio streams, especially those defined by MPEG, but can also be used to store other data such as subtitles and still images. Like most modern container formats, MPEG-4 Part 14 allows streaming over the Internet. A separate hint track is used to include streaming information in the file. The only official filename extension for MPEG-4 Part 14 files is .mp4.
Associated programs
Apple QuickTime Player Apple iTunes Microsoft Windows Media Player VideoLAN VLC Media Player
Using Zamzar it is possible to convert MP4 files to a variety of other formats:
mp4 to 3gp (3GPP Multimedia File) mp4 to 3g2 (3GPP2 Multimedia File) mp4 to aac (Advanced Audio Coding File) mp4 to ac3 (AC3 Audio File) mp4 to avi (Windows video file) mp4 to flac (Free Lossless Audio Codec) mp4 to flv (Flash video) mp4 to gif (Compuserve graphics interchange) mp4 to ipad (MPEG-4 (H264) Video File) mp4 to iphone (MPEG-4 (H264) Video File) mp4 to ipod (MPEG-4 Video File) mp4 to mov (Apple QuickTime Movie) mp4 to mp3 (Compressed audio file) mp4 to mpg (Moving Picture Experts Group File) mp4 to ogg (Ogg Vorbis Compressed Audio File) mp4 to wav (Windows audio file) mp4 to webm (Multimedia Container Format) mp4 to wmv (Windows Media Video)
AAC is similar to MP3. It essentially cuts out, or compresses, information that the human ear cannot pick up thereby making digital files smaller and more easily managed and therefore quicker to download. AAC is about half the size of MP3 but with better quality. It is at least one tenth the size of CD digital data. Apple are the biggest users of this format and if you have an iPod or iPhone then you will have come across this format as it is iTunes default audio format.
AAC is similar in concept to MP3 but goes further. It too compresses digital audio files but to a bigger degree. It is also part of the MPEG-4 standard, it is most widely used to create small digital audio files. The current variant is specified in ISO/IEC standard 14496-3. Like MP3, AAC is a lossy algorithm. The human hearing system cannot hear quiet sounds in the presence of loud sounds of a similar frequency; for example, a voice conversation cannot be heard while an aeroplane flies low overhead. This is known as auditory masking, this allows the discarding of data with minimal loss of quality.
Associated programs
KMPlayer RealPlayer VideoLAN VLC Media Player Windows Media Player iTunes
Developed by
A combination of Fraunhofer IIS, AT&T Bell Laboratories, Dolby and Sony Corporation
