MP4 and M4A
MP4 is a multimedia container format which, due to the considerable opportunities, gained in recent years great popularity. Like most modern container formats, MP4 allows streaming over the Internet, and it is widely used by many video sites, including YouTube.
In MP4 files can be embedded video streams (mostly encoded with H.264 video encoder), audio streams (AAC, sometimes MP3 and other), metadata and subtitles.
M4A file is a regular MP4 file, but with audio stream only and with .m4a extension. Audio streams embedded in M4A files are usually encoded with AAC (Advanced Audio Coding), sometimes with ALAC (Apple Lossless).
More information about the MP4 format can be found at https://en.wikipedia.org/wiki/MPEG-4_Part_14.
M4A to MP3 conversion using Free MP4 to MP3 Converter
Starting the program and adding M4A files to the processing list
When you install and run the program, the main window will appear.
To convert M4A files, you must first add them to the processing list. To do this, click thebutton and specify the desired M4A files. They appear on the list. Files can also be added using drag and drop.
Conversion using profiles
The program includes a number of conversion profiles designed for the typical conversion tasks. They are available on the Profile drop-down list. To use one of profiles, simply select it on this list.
If you do not have experience in converting audio files, select the profile named Default encoder settings and click the button to start the conversion.
At default settings, the application converts M4A files to MP3 using constant bitrate encoding (CBR), and automatically selects all the encoding parameters so as to preserve the original audio quality.
When you add M4A files to the list, the next step is to set the output format to MP3 - MPEG-1 Layer 3 in the Audio section.
The next step is to select the desired bitrate mode and bitrate value.
You can choose CBR mode (constant bitrate), ABR mode (average bitrate) or VBR mode (variable bitrate). If you select VBR, you must also select one of the presets on the LAME presets list. The Standard preset is usually a good compromise between sound quality and size the output MP3 file.
If you choose CBR or ABR bitrate mode, you must also set audio bitrate on the bitrate list. If you set Auto, the program will select audio bitrate automatically in order to preserve sound quality, and size of the resulting MP3 file will be very close to size of the input M4A file.
Some older MP3 players support only MP3 files encoded at a constant bitrate - CBR.
Parameters Sampling frequency and Channels (the number of audio channels in the output file) is best left in the positions Auto, then the program automatically selects the appropriate values.
Using the Volume slider you can adjust the sound level in the resulting MP3 file. When set to
1x, the volume will not change.
When you add M4A files to the processing list and set all the necessary parameters, you can already start the conversion by clicking the Conversion window will appear, where you can track the progress of the operation.button. The
With default settings, the converted files will appear in the same directory that contains the source files. You can change output folder in the Output section. Generated MP3 files will have the same name as M4A files, only the extension is changed to .mp3.