How to Convert AU to MP4 — Quick & Free
Fast, instant AU to MP4 conversion. No signup required. Just drop your .au file and get .mp4 in seconds.
Batch Settings
您是否曾遇到这样的情况：手头有一些高质量的AU音频文件，却发现它们在微信朋友圈、短视频平台分享时遇到阻碍，或者在某些移动设备上无法直接播放？AU文件以其未压缩的音质而受到专业人士的青睐，但在日常分享和跨平台兼容性方面，MP4无疑是更优的选择。MP4不仅支持视频，也能完美封装音频，且兼容性极佳，文件体积适中，是目前互联网上最受欢迎的媒体格式之一。将AU转换为MP4，能让您的音频内容拥有更广阔的传播空间，无论是教学录音、原创音乐小样，还是游戏精彩瞬间的背景音，都能轻松触达更多听众，享受无缝的分享体验。
- 微信视频号背景音乐
- 手游精彩集锦配音
- 在线课程或讲座分享
在大陆和台湾地区，用户对媒体文件的兼容性和便捷分享有较高要求，尤其是通过微信、抖音等平台传播时，MP4格式的普适性使其成为首选。新加坡用户也普遍通过移动设备分享内容，MP4同样是主流。
About AU to MP4 Conversion
Short answer: yes, you can convert AU to MP4 online for free, and quality is well preserved with the right settings. Just upload your .au file to CocoConvert, pick MP4 as the output, and click Convert. The whole process takes seconds.
Now for the details. AU is a widely used file format. MP4 (MPEG-4 Part 14) is the universal video container supporting H.264/H.265 codecs — plays on virtually every device. Converting between these two formats lets you convert between formats quickly.
Your AU file is decoded and re-encoded as MP4. Converting AU to MP4 maintains high quality with CocoConvert's optimised encoder settings.
CocoConvert runs entirely online — no software to install, no account to create. Your files are encrypted during upload (TLS), processed on isolated servers in Germany, and permanently deleted after 24 hours. It works in Chrome, Safari, Firefox, Edge, and all mobile browsers.
Need to convert more than one file? Free users can do 5 per hour. Pro gets 100 per hour with files up to 5 GB each.
How to Convert AU to MP4
- 1
1. Upload AU
Drop your .au file onto the page (or tap "Browse" on mobile). Add multiple files for batch conversion.
- 2
2. Select MP4
Choose .mp4 from the output dropdown. Settings are pre-configured for best results.
- 3
3. Convert
One click. The server handles all the heavy lifting using FFmpeg and Sharp.
- 4
4. Download
Your .mp4 file is ready. Download it directly or get all files as a zip archive.
What Happens When You Convert AU to MP4
Your AU file is decoded and re-encoded as MP4.
Your AU file is uploaded and validated
The file is decoded (parsed into its raw data)
The data is re-encoded in MP4 format
The converted file is ready for download
Format Comparison
AU
.au file
| Extension | .au |
| MIME Type | audio/basic |
| Category | Audio |
MP4
.mp4 file
| Extension | .mp4 |
| MIME Type | video/mp4 |
| Category | Audio |
Should You Convert AU to MP4?
When to Convert
- ✓When you need a MP4 file
Frequently Asked Questions
Is AU to MP4 conversion free?
Yes. CocoConvert offers free AU to MP4 conversion with generous daily limits — 25 minutes of processing time and up to 5 files per hour (250 MB each). Pro plans remove these limits.
How fast is AU to MP4 conversion?
Most files convert in 2–10 seconds depending on size. Large audio files may take 30 seconds. Batch jobs process in parallel for maximum speed.
What happens to my files after conversion?
Your uploaded AU file and the converted MP4 file are both automatically deleted from our servers within 24 hours. They are never shared, sold, or analysed.
Does converting AU to MP4 lose quality?
Converting AU to MP4 maintains high quality with CocoConvert's optimised encoder settings.
Can I convert MP4 back to AU?
Yes, CocoConvert supports MP4 to AU conversion as well. However, if the original conversion involved lossy compression, converting back won't recover the lost data.
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