How to convert smartphone recordings (M4A) to MP3 and play/edit on a computer
As a countermeasure for when you cannot open an "M4A" file recorded with a smartphone's voice memo on a computer, etc., we will explain in detail the characteristics of various audio formats (MP3/WAV/WebM), how to choose an appropriate bit rate, and the procedure for safely converting audio within the browser without the need for communication.
§1. I sympathize with this problem: I can't play important conversations recorded on my smartphone on my computer!
“I recorded the minutes of a meeting or a lecture perfectly using the voice memo app on my iPhone or Android, but when I transfer it to my computer, I can’t open it and I’m getting frustrated…”
"When I try to load audio data into the voice transcription AI service, I get an error saying 'The file format is not supported' and it doesn't proceed..."
"I looked for an audio conversion tool on the internet, but I'm worried about the amount of data I'll have to upload a heavy audio file that's several minutes to several hours long, and since the conference audio is confidential, I can't send it because I'm afraid it will be leaked..."
There are many cases where audio recordings from classes or business cannot be used on a computer, and it is difficult to know how to convert highly confidential data. Because conference conversations and dialogues contain a lot of sensitive information, online conversion sites cannot be used easily.
§2. Explanation of the cause: The compatibility barrier of the M4A extension and the trap of capacity and sound quality settings
Most audio files recorded on smartphones are saved in the M4A (MPEG-4 Audio) format.
M4A is an excellent format that provides high sound quality and keeps the file size small, but it is less compatible than the world standard MP3 and the Windows standard WAV. The cause of the error is that old playback software and some automatic transcription tools still cannot directly open M4A files.
When performing audio conversion to solve these problems, it is necessary to specify appropriate sound quality settings (bit rate).
- Recording speech: The bit rate is around 128 kbps, which is enough to hear clearly and significantly reduce the file size. If you set the number of channels to "monaural", the capacity will be further halved.
- Music recording: If musical instruments or background music is included, it is best to set it to 192-320 kbps (stereo) to prevent sound quality deterioration.
Additionally, when using a general "free audio converter", large audio files are sent to a web server via the Internet.
Several hours worth of recorded data can amount to hundreds of MB, consumes a huge amount of mobile communication (giga), and raw meeting data is stored on an external server for a long period of time, which poses a serious security risk.
§3． Solution using tools: ZeroTools audio converter is a safe solution with zero giga consumption.
"I want to convert the meeting content to MP3 right away without leaking it or consuming gigabytes..."
Our site's audio file mutual conversion tool is a 100% solution to these security and traffic issues.
This tool utilizes the browser's graphics and sound API (Web Audio API) to perform audio conversion (encoding) processing in a completely local environment (within your device). Since no data is sent over the Internet, it is safe and does not consume communication traffic.
Solution steps
1. Open the Audio file mutual conversion tool page.
2. Specify the .m4a audio file you want to convert from "Select file" or load it by drag and drop (it will be loaded immediately as it is a local process).
3. Select the output format (MP3, WAV, OGG, WebM, etc.).
4. Specify the bit rate (128kbps is recommended for human voice) and channel (monaural).
5. Click "Start conversion" and when the process is finished, click "Save converted audio" to download.
This is the most comfortable and reliable method when you want to process large volumes of voice data with safety first. Please make use of it in your daily work.