AAC to MPA: Convert Audio from AAC(Advanced Audio Coding) to MPA(MPEG Audio) with River Past Audio Converter, AAC2MPA converter, conversion

What is AAC?

AAC, Advanced Audio Coding, is a technique for compressing digital audio files. Officially part of the MPEG-4 standard, it is most widely used to create small digital audio files.

AAC is conceptually similar to the ubiquitous MP3 format. AAC is a lossy algorithm, meaning the original digital audio cannot be recreated from the compressed bits alone. In terms of audio fidelity, however, there is no loss of data if the compressed audio is properly encoded. AAC claims an advantage over MP3 in this regard: while MP3 requires a bit rate of approximately 256 kilobits per second (kbps) to achieve transparency, AAC can achieve the same quality at 128 kbps. This allows AAC files to be roughly half the size of MP3 files of the same quality, and one-tenth the size of CD digital data.

AAC provides several other advantages over MP3. It is capable of handling much higher and lower frequencies of sound, provides up to 48 channels of audio, and allows the creation of low-latency audio necessary for two-way communication.

There are two types of AAC files. The most common one is embedded in MPEG-4 container. Its file extension is usually m4a. The popular iTunes encode AAC audio in this format. You only need to have Apple QuickTime installed to decode these files.

A less common one is the plain AAC file, usually with .aac file extension. To convert from this type, you need to have DC-Bass Decoder installed.

What is MPA?

There are three "layers" in the MPEG-1 Audio specification.

In MPEG Audio Layer-1, a simple 32-subband audio compressor using a floating point representation for subband samples. Resolution and scale factor are stored for groups of 12 subsamples. MP1 is only used for Philips DCC Digital Compact cassette with data rates of 384 kbps.

Both MPEG-1 and MPEG-2 files use MPEG-1 Audio Layer-2.

MPEG-1 Audio Layer-3 becomes the widely popular MP3.

MPEG.ORG is an excellent source for additional information on MPEG format and usage.

To encode MPEG Audio, you will need River Past MPEG-2 Booster Pack in addition to your audio software.

Additional Requirements

To convert from AAC(Advanced Audio Coding) to MPA(MPEG Audio) audio with River Past Audio Converter, you must have River Past MPEG-2 Booster Pack installed.

Launch River Past Audio Converter

Once River Past Audio Converter is installed properly, launch Audio Converter.

Add File

Click on the "Add File" button on the tool bar. The standard file open dialog appears. Select "AAC - Advaned Audio Coding" in its "Files of type" combo box.

Note: To convert from AAC files, you must have DC-Bass Decoder installed.

River Past Audio Converter

Select Output Format

Use the setting panel on the bottom of the window to control the output format. Click on the toggle to the left of the "Format" label to expand the panel. Select "MPA - MPEG Layer-2" as the "Audio Type".

You can change the sample rate, channel (stereo or mono) and bits/sample, and bitrate.

Note: The MPEG-2 Booster Pack must be installed for the "MPA - MPEG Layer-2" output option to show.