Where MP3 recordings usually come from
MP3 is still the most common format for spoken audio. Podcast episodes are almost always distributed as MP3. Many handheld voice recorders and portable recorders can save straight to MP3 so the files stay small on the memory card. Call recording apps on Android, audio exported from Audacity or GarageBand, and lecture recordings shared by teachers often arrive as MP3 too.
Because the format is so widely supported, people also convert other files to MP3 before sharing them. That is fine, but if you still have the original recording, upload that instead. RocketScribe accepts the original formats directly, and every extra conversion loses a little detail.
Long MP3s such as full podcast episodes or day-long lectures are fine to upload. Files are sent in parts, so if your connection drops, Retry continues where it stopped instead of starting the upload again.
How MP3 compression affects an MP3 to text conversion
MP3 is a lossy format. The encoder throws away parts of the sound that listeners are less likely to notice. Speech survives this well at moderate bitrates. A voice recording at 64 kbps mono or higher usually transcribes as well as an uncompressed file of the same recording.
Problems start at very low bitrates, or when a file has been decoded and re-encoded several times. You may hear a watery, swishy texture on the voice. That texture smears consonants like s, f and th, and those are exactly the sounds speech recognition needs to tell words apart. Converting a low-bitrate MP3 to a higher bitrate will not help, because the lost detail cannot come back.
Stereo or mono makes no difference for the transcript. Every file is mixed down to a single track before recognition. If a call recorder put each person on a separate channel, both channels end up in the same transcript.
What you get after the upload
The transcript comes back split into paragraphs with timestamps. A player sits under the text and highlights the line being spoken, so you can listen and read at the same time. Click any line to jump to that point in the audio. If a name or term is wrong, edit the text in place. On paid plans the transcript can also show who said what, and you can rename the speakers from generic labels to real names.
Which export fits which job
You can turn timestamps and speaker names on or off before you export, so the same transcript can serve several purposes.
- TXT: plain text for notes, search, or pasting into another tool.
- DOCX (Word): interview transcripts and meeting minutes you want to format, comment on or send.
- PDF: a fixed copy for records or for people who should not edit it.
- SRT or VTT: subtitle files if the MP3 is the soundtrack of a video you are editing.
- CSV: one row per line with timestamps, useful for research coding or spreadsheets.
- AI prompt: copies the transcript with a ready-made prompt so you can ask ChatGPT or Claude for a summary or action items.
- Share link: a read-only page you can send to someone who does not need an account.
Honest notes on accuracy
RocketScribe uses modern Whisper-class speech recognition. A clear voice recorded close to the microphone transcribes very well. Accuracy drops with background noise, people talking over each other, music under the voice, a recorder placed far from the speaker, and strong accents. Podcast intros with music beds are a common example: the talking part is usually clean, and the first few seconds over the jingle may need a quick edit.
The language is detected automatically, but you can also choose it per file. Setting it yourself helps when a recording opens with a greeting in a different language from the rest. Recordings that mix Chinese and English in the same conversation are handled too.