Extract Audio from DV to AU — Free Online Tool
Extract audio from DV camcorder footage and save it as a Sun AU file, converting the native PCM 16-bit little-endian audio track to PCM 16-bit big-endian format. This tool is ideal for archivists and Unix/Linux users who need to pull clean, uncompressed audio from DV tape captures in a format native to Sun and Unix systems.
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FFmpeg Command
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Estimated output:
Conversion Complete!
DownloadHow It Works
DV files store audio as uncompressed PCM signed 16-bit little-endian (pcm_s16le) alongside the DV-compressed video stream. This conversion drops the video stream entirely and re-encodes only the audio, flipping the byte order from little-endian to big-endian (pcm_s16be) to comply with the AU format specification. Because both the source and destination are uncompressed PCM, there is no perceptual audio quality loss — only the byte ordering and container header change. The result is a raw PCM audio file wrapped in the simple Sun AU header, which stores minimal metadata: sample rate, channel count, bit depth, and a short annotation field.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg program, the open-source multimedia processing engine that handles reading the DV container, demuxing the audio stream, and writing the AU output file. |
-i input.dv
|
Specifies the input DV file. FFmpeg reads the DV container, identifying the dvvideo video stream and the pcm_s16le audio stream embedded in the tape-originated or file-based DV format. |
-vn
|
Disables video output entirely, instructing FFmpeg to ignore the dvvideo stream. Since the goal is audio-only extraction, this prevents any attempt to encode or include DV video in the AU output, which would fail anyway as AU is a purely audio-only format. |
-c:a pcm_s16be
|
Sets the audio codec to PCM signed 16-bit big-endian, which is the default and most compatible encoding for the Sun AU format. This converts the DV source's pcm_s16le audio by swapping byte order, preserving full 16-bit fidelity with no lossy compression. |
output.au
|
Specifies the output filename with the .au extension, which tells FFmpeg to wrap the encoded PCM audio in a Sun AU container with the appropriate magic number and header fields including sample rate and channel count inherited from the DV source. |
Common Use Cases
- Archivists digitizing DV tape recordings who need to store audio on Unix or Linux systems in a native, widely-readable PCM format.
- Audio engineers pulling isolated PCM audio tracks from DV camcorder footage for use in legacy Unix-based digital audio workstations.
- Researchers working with oral history or field recording archives stored on DV tape who need to extract audio for analysis in scientific or signal-processing tools that accept AU files.
- Developers building audio pipelines on Sun Solaris or BSD systems that natively consume AU files and need to ingest audio sourced from DV video captures.
- Educators converting DV-format interview or documentary footage into standalone AU audio files for use in university Unix computing environments.
Frequently Asked Questions
No — the audio quality is preserved without any perceptual loss. DV stores audio as pcm_s16le (16-bit signed PCM, little-endian), and AU uses pcm_s16be (16-bit signed PCM, big-endian). The only transformation is a byte-order swap, not a compression or re-quantization step. Both formats represent the same audio data at the same bit depth and sample rate, so the resulting AU file is sonically identical to the original DV audio track.
The AU file will inherit whatever sample rate is embedded in the DV source file. DV camcorders typically record audio at either 48000 Hz (the broadcast standard for DV) or 32000 Hz, depending on the recording mode used. FFmpeg reads the sample rate from the DV container and passes it through directly into the AU header, so no resampling occurs unless you explicitly add resampling flags to the command.
Yes. The Sun AU format supports multiple audio channels, so if your DV footage contains a stereo audio track (two channels, which is standard for DV), the output AU file will also be stereo. FFmpeg passes the channel layout through unchanged. If your DV source has a 4-channel recording (supported by some DV variants), you should verify downstream compatibility, as some legacy AU players assume mono or stereo.
The AU format supports several PCM variants including pcm_s16be, pcm_s8, pcm_u8, pcm_alaw, and pcm_mulaw. The command uses pcm_s16be because it is the AU default and provides the highest fidelity match to the DV source's 16-bit PCM audio. To use a different codec, replace '-c:a pcm_s16be' with your preferred option, for example '-c:a pcm_mulaw' for G.711 mu-law encoding, which produces a smaller file but with lossy compression suited for telephony use cases.
You can batch process files with a shell loop. On Linux or macOS, run: for f in *.dv; do ffmpeg -i "$f" -vn -c:a pcm_s16be "${f%.dv}.au"; done. On Windows Command Prompt, use: for %f in (*.dv) do ffmpeg -i "%f" -vn -c:a pcm_s16be "%~nf.au". This iterates over every DV file in the current directory and produces a matching AU file, which is especially useful when digitizing multiple DV tapes.
Very little metadata is preserved. The Sun AU format has a minimal header that stores only the audio encoding type, sample rate, channel count, and an optional free-form annotation string. It does not support rich metadata fields like track title, artist, or creation date. Any metadata embedded in the DV container — such as tape timestamps or camcorder-generated fields — will not carry over to the AU file. If metadata preservation matters, consider extracting to a format like FLAC or WAV instead.
Technical Notes
DV files use intra-frame DCT compression for video but store audio as fully uncompressed PCM, which means the audio extraction step in this conversion involves no lossy decoding — only the DV video stream is discarded. The byte-order conversion from little-endian (DV/PCM) to big-endian (AU/PCM) is computationally trivial and introduces no rounding or quantization error. The Sun AU format uses a fixed magic number (0x2e736e64, or '.snd') at the start of the file and a simple fixed-size or variable-size header, making it easy to parse programmatically. One known limitation is that AU does not support chapters, cue points, or loop markers, so any structural information you might want to associate with segments of a DV recording must be tracked externally. Additionally, AU files produced this way will not contain a total data length in the header if FFmpeg cannot seek the output (e.g., when writing to a pipe), resulting in a header data_size field of 0xFFFFFFFF — this is valid per the spec but may confuse some older players. For files larger than 1GB, the FFmpeg command displayed on this page can be run locally on your desktop without any file size restriction.