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.
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WAV (WAVE) files are audio files playable via multimedia playback software such as Windows Media Player and other software available for your operating system. These files contain any sounds such as sound effects, music or spoken words. WAV files are large in size and with the advent of MP3 and MP4 WAV files are becoming less popular and less common. They were created and developed by IBM and Microsoft but unlike MP3 and MP4 the WAV file format does not use a form of lossy compression so file sizes are therefore much bigger and now less popular.
Wav files are the standard digital audio format in Windows. Using the .WAV file extension, 8- or 16-bit samples can be taken at rates of 11,025 Hz, 22,050 Hz and 44,100 Hz. The highest quality being th 16-bit at 44,100 HZ, this highest level is the sampling rate of an audio CD and uses 88KB of storage per second. All general sounds in Windows, such as when you log in, are in the .WAV format. The default content of a WAV file is uncompressed (although they can be used to store compressed formats such as MP3), pulse code modulated (PCM) digital samples derived from the analog source.
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