By default a static frame: the M4A file's embedded cover art if present, otherwise a solid background. The frame is held for the full duration of the audio, so the MP4 file is a single still image with your M4A audio as the soundtrack — small and fast to encode.
Will the MP4 video lose any audio quality versus the M4A source?
Not in this one-step converter — it uses the embedded M4A cover art or a default background. To set a custom still or a looping clip behind the audio, convert M4A to MP4 here first, then use /video-editor/ to swap the visual track.
Yes — drop the full set of M4A files in and each becomes its own MP4 video in parallel. Premium runs more workers, so a 12-track album finishes far faster than converting each M4A one at a time.
转换 MP4 期间 我的 M4A 文件是否私有?
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Yes — uploaded M4A files are processed in isolated workers and deleted within minutes. We never listen to, retain, or share your audio. The full retention window is documented at /privacy/.
