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MP4 to AAC

Convert .MP4 into .AAC Files - Fast, Free and Secure. We also have information of .MP4 and .AAC Files extensions on this page.

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Information about MP4
File extension
mp4
File category
Video
Stands for
MPEG-4 Video stream
Developer
Moving Picture Experts Group
Overview
It stores multimedia data. It is commonly used by manufacturers (those produce mobile products) as well as by Apple for audio, video and still images. It offers higher flexibility and is compatible with both audio and video files. The Format provided by these files i.e MPEG-4 is commonly used online for streaming the videos. Any Movie, video or Audio file can be easily downloaded or streamed online with this extension which can be free or chargeable as well, such as downloading from iTunes. The payment can be made using credit or debit cards. These files may also include audio books, photos, podcasts, songs, movies, not making them limited to just audios and videos. This format has become more common as they are being used in iPod and PlayStation Portable(PSP). Commonly portable media players are advertised as “MP4 players” although they are capable of playing other media format as well like ‘AMV format'.
Technical description
MPEG-4 files are officially named under extension .mp4 and this is the only official extension for MPEG-4 PART-14 formats. These files were introduced in 2001 under the standards of ISO/IEX 14496-1:2001. It runs on AAC encoding which restricts the users from copying the data of the files. The data embedding can be done on these files using any private stream. For instance, hint tracks to add the streaming information into the file. These files are similar to most of the modern containers containing data information which allows internet streaming.
Links
wikipedia.org
Information about AAC
File extension
aac
File category
Audio
Stands for
Advanced Audio Coding
Developer
Bell Labs, Fraunhofer IIS, Dolby Laboratories, LG Electronics, Sony Corporation (Combined Efforts)
Overview
AAC is the descendant of the MP3 format. It provides better sound quality using a similar bit rate as of MP3. Besides this, it uses lossy data compression but it has high standards of audio quality than of MP3. We can find this format on a number of platforms and Apple's iTunes is one such example that uses it as default audio format. Size of its file is much smaller which is approximately one-tenth of MP3 file. It also neglects the redundant information that is not even processed by the human ear and is often not noticed. Although, this format was introduced as MPEG-2 Part-7, yet, standardization was done by ISO/IEC as a part of the MPEG-2 and MPEG-4 families. It is also termed as MPEG-2 NBC (Non- Backward Compatible) because it is incompatible with MPEG-1 audio formats i.e. MP1, MP2, MP3.
Technical description
Modified discrete cosine transform(MDCT) algorithm is used by AAC which ensures that it provides high compression efficiency. MPEG-2 PART-7 has three default profiles namely Low Complexity (LC), Main Profile (Main) and Scalable Sample Rate (SSR). These profiles come with Perceptual Noise Substitution which enhances coding efficiency and provides excellent audio quality. Furthermore, it uses Auditory Masking to ignore the surplus information. This codec has come up with advanced features which are not available in the predecessor. These include additional sample rates ranging from 8 to 96 kHz, 48 Channels, better efficiency with a simpler filter bank, higher coding efficiency for stationary signals and higher coding accuracy for transient signals.
Links
wikipedia.org
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