Upload your WebM video. PDF.to pulls the audio track out, encodes it to M4R, and gives you a M4R-only download. The video stream is discarded.
Will the audio in the M4R match the original WebM quality?
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If the source audio is already in a codec compatible with M4R, we stream-copy without re-encoding — bit-identical to the original. Otherwise we re-encode at 192 kbps by default for near-transparent quality.
Yes, within the free size limit. PRO supports much larger WebM files and parallel batch extraction.
Does PDF.to read or store my WebM content?
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No. The WebM video and the M4R audio output are deleted within an hour. Conversion runs in an isolated worker.
Can I batch-extract audio from multiple WebM files?
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Yes — drop a folder of WebM videos and you will get a ZIP of M4R files back, one per source video.
Will the M4R preserve tags and metadata?
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Title, artist, and album tags are populated from the WebM container metadata when available. You can edit them after extraction with our audio-tag tool.
转换器是否对流视频 URL 工作?
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No — PDF.to converts files you upload, not third-party stream URLs. Download the WebM legally first, then upload it for M4R extraction.
Why is the M4R file much smaller than the WebM video?
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Because the video stream (typically 90%+ of file size) is discarded. Only the audio track ends up in the M4R, which is why it can drop from gigabytes to a few megabytes.
