You need to convert a WAV file, changing the sample rate, the bit depth, or both. So you open a converter, process the file, and check the result. The audio sounds fine. But the metadata is gone. The timecode is missing. The scene number, the track names, the project info, all stripped.
This happens more often than it should, and it creates real problems in post-production. Here's why it happens, and how to avoid it.
Why most converters lose metadata
WAV file converters are generally built around one goal: changing the audio format. They read the audio samples, resample or re-quantize them, and write a new file. The metadata lives in separate chunks inside the WAV file, like the bEXT chunk and the iXML chunk, and it is either ignored entirely or never copied to the output.
From the converter's perspective, the job is done. From a post-production perspective, the file is now missing critical information that editors, DAW systems, and conforming software depend on.
What metadata gets lost
When a converter strips WAV metadata, here's what disappears:
- Timecode: the BWF timecode reference stored in the bEXT chunk. This is how DAWs know where in the timeline to place the audio. Lose this, and automatic conform breaks.
- Scene and take numbers: used by editing systems to match audio to picture
- Track names: which channel is the boom, which is the lav
- Project name and originator info: traceability and archival data
- Cue points: the sync markers the recorder dropped into the take
- iXML data: the full production metadata written by your field recorder
For a location sound recordist handing off to post, or a post-production house delivering to a broadcaster, this metadata is not optional. It's part of the deliverable.
The timecode problem specifically
Timecode in a WAV file is stored as a sample count in the bEXT chunk, the number of samples from midnight to the point of recording. That value is tied to the original sample rate. Convert the sample rate without recalculating it and the timecode becomes wrong. Strip the bEXT chunk entirely and the timecode disappears.
Either way, any DAW or conforming system that relies on the embedded timecode will now get the wrong result, or nothing at all.
How Wave Copilot handles conversion differently
Wave Copilot is built for professional audio workflows, which means metadata preservation is not an afterthought. It is part of the conversion process.
When you convert a file in Wave Copilot:
- All bEXT metadata is carried over: description, originator, originator reference, origination date and time
- Timecode is recalculated correctly: the BWF timecode reference value is adjusted for the new sample rate, so the timecode still reads the same in the converted file
- iXML data and cue points are preserved: all production metadata written by your field recorder stays intact
- Audio quality is maintained: dither is applied when you reduce bit depth, and you choose the resampler yourself
The options you actually get
Convert Format sits on the file list's right-click menu, and under File > Convert Format (Ctrl/Cmd + K).
- Output format: WAV, MP3, or AAC (M4A)
- Sample rate: 44.1, 48, 88.2, 96, 176.4, or 192 kHz for WAV; 44.1 or 48 kHz for the lossy formats
- Bit depth: 16-bit, 24-bit, 32-bit integer, or 32-bit float
- Dither, offered when you reduce bit depth: None, Rectangular TPDF, Triangular TPDF, or Lipshitz Noise Shaping
- Resampling quality, offered when the sample rate changes: Linear, Cubic, Sinc, or SoX Resampler
- Audio level: normalize every channel to -1 dBFS, or leave the levels alone and only pull the gain back on files that would clip, which is the one to reach for with 32-bit float sources
Outputs are written into a subfolder named after the target format, '48000Hz_24bit' for example, either under a folder you pick or beside each source file if you choose Same as Source. The whole selection converts in parallel.
MP3 and AAC keep their timecode too
MP3 and AAC (M4A) have no bEXT chunk, so a lossy file cannot carry broadcast metadata the way a WAV does. Wave Copilot writes the start timecode into the filename, as 'filename_11-02-55-00.mp3', and into the file's tags: ID3v2 TXXX frames for MP3, key-value atoms for M4A, alongside the sample rate, originator, and description where the source carries them. A review MP3 that still says where it belongs on the timeline is worth considerably more than one that doesn't. For a full metadata round trip, deliver WAV.
A poly source has to be folded down to two channels for MP3 or AAC, and you choose how: mix every channel down to stereo, or keep only channels 1 and 2, which is what you want when the first pair is your mix.
A practical example
You recorded a documentary at 96 kHz, 32-bit float. Your broadcast delivery spec requires 48 kHz, 24-bit. You have 120 files from three shooting days, all with bEXT and iXML metadata written by your Sound Devices recorder.
In Wave Copilot you select all 120 files, open Convert Format, set the output to 48 kHz and 24-bit, choose Lipshitz Noise Shaping, pick a destination, and click Convert. Every file is processed, the timecode is recalculated for each one at the new sample rate, and all the original metadata is written into every output file.
The editor receives 120 files that auto-conform correctly in the DAW, with all scene and take information intact, and timecode that lands where it should.
Conclusion
If your WAV converter is stripping metadata or breaking timecode, it's adding invisible work to every downstream step of your project. Wave Copilot handles conversion the right way: audio quality and metadata, together. Free 14-day trial for Windows, macOS and Linux.