Decide what the audio copy is for
An interview video can contain more than one useful deliverable. The video may be the publication version, while an audio file helps an editor review answers during a journey or lets the interviewee check an approved passage. Those uses do not all require the same file. A small MP3 can be a practical listening copy; an uncompressed working file may fit a particular editing system. Keep the original recording when you have it.
Before extracting speech, confirm that the recording agreement allows the intended use. Consent to appear in a video is not automatically consent to every audio-only publication. An internal review copy, a podcast release and a commercially distributed clip should be considered separately.
Start with the best available recording
If you recorded a separate microphone track, that may be more useful than extracting audio from a compressed online publication. Look for the original audio file, production export or approved master first. A website download can recover an available stream, but it cannot reconstruct the microphone signal that existed before compression or repair details absent from the source.
For a source hosted online, use an individual link that FIRST supports and that you are authorised to download. The website does not take your private platform passwords. If the material requires unsupported authentication, ask the owner for the recording or use the platform’s permitted export tools.
Understand MP3 and the alternatives
MP3 is a compressed audio format with broad playback support. FIRST’s MP3 export uses a 192 kbps target. M4A/AAC is another compressed choice, while OPUS and OGG/Vorbis may suit devices or workflows that support them. Pick the format for the player and purpose rather than assuming one suffix is best for every task.
WAV, AIFF and FLAC are also offered through the processing server. They describe uncompressed or losslessly encoded outputs, not a restoration service. Converting a compressed online stream to WAV does not recover discarded detail. It can produce a much larger file that still contains the same source limitations. Keep that distinction in any handover notes.
Budget for duration and size
At a constant 192 kilobits per second, an hour of audio corresponds to about 86.4 million bytes before container overhead. That is a rough planning calculation, not a promise that every MP3 download will have exactly that size. The source duration, encoding behaviour and container can affect the result, and the browser may display units differently from a storage vendor.
FIRST marks estimates as approximate. Some variable-rate or lossless outputs have no meaningful pre-download size prediction. The website’s current output ceiling is 2 GB, so large PCM exports may need a different available format. An interview longer than an hour still uses one successful-download slot from the three-download trial.
Create the listening copy
On a phone or desktop browser, open FIRST and paste the permitted video link and choose Audio. Select MP3, inspect the returned format choice and start preparation. The server retrieves the source and converts the audio; the phone does not need a Chrome extension or a local FFmpeg installation. Wait until a save link is shown before leaving the page.
Save the file to the destination you control. Server preparation and the final browser transfer are separate steps. Temporary output links expire, so do not treat a page left open overnight as an archive. If processing fails or you cancel before a successful transfer, the reserved trial allowance is released.
Listen for the right things
Open the saved file locally and check several points: the opening, a change of speaker, a quieter answer and the ending. Confirm that both sides of the interview are present if the original used separate channels. Check that the duration is reasonable and that there are no obvious gaps. A valid audio file can still be the wrong take or an incomplete source recording.
FIRST extracts or converts audio; it does not provide automatic noise removal, transcript correction, speaker separation or editorial approval. If the interview needs those tasks, use an appropriate editing workflow and keep a record of any changes. Do not describe an unreviewed extraction as a finished podcast master.
Label the file for the recipient
Use a clear name such as project, interviewee, recording date and “review copy”. If public naming would expose personal information, choose an internal project identifier instead. Include a short note telling the recipient whether they may share the file, which version it represents and whether it is for approval rather than publication.
Store the permission and release documents separately with restricted access. Avoid sending a temporary FIRST preparation link to someone as the only copy: the link can expire and is tied to your browser session or restored purchase. Use a distribution method appropriate to the sensitivity of the conversation and the rights you hold.
Choose what to keep after review
Retain the original and approved final outputs for the period your project requires. Remove redundant listening copies where they contain private or sensitive conversations and no longer serve a purpose. If a participant requests a correction or deletion, evaluate the request under your agreement and applicable obligations rather than assuming an MP3 conversion removes their interests in the recording.
A strong audio workflow is modest and explicit: preserve the best original, create a compatible listening copy, verify what was exported and share it for a defined purpose. That makes the MP3 useful without mistaking compression settings for editorial quality or treating a convenient conversion as permission to republish.