Convert FLV to MP3 - extract audio
FLV was Flash's video container - dead as a platform, still full of archived content people want the audio out of. Wave copies the audio when it's already MP3, and re-encodes cleanly when it's AAC or Speex.
What actually changes
Flash Video files come in two eras: pre-2008 FLVs carried Sorenson Spark or VP6 video with MP3 or Speex audio, and post-2008 FLVs typically carry H.264 with AAC. Wave inspects the audio track and takes the fast path when it can. If the audio is already MP3, extraction is a bit-exact stream copy - no re-encoding, no quality loss, seconds on any laptop.
When the source is AAC or Speex, Wave decodes and re-encodes to MP3 through libmp3lame at VBR around 190 kbps. Because the video track is discarded entirely, extract runs several times faster than a full video conversion. Old FLV podcasts, tutorial videos, and Flash-era webinars are the most common inputs - often with MP3 audio already, which lands in the fast path.
Three steps.
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01
Step 1
Drop the FLV file onto the card.
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02
Step 2
Pick MP3 as the output format.
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Step 3
Convert and save the MP3.
Answers, specifically.
If my FLV already carries MP3, is it lossless?
Yes - a straight stream copy, byte-for-byte. No decode, no re-encode. That's the fast path Wave takes whenever the source audio is already MP3.
What about the Speex codec - will it decode?
Yes. Speex is bundled in Wave's wasm engine. Speex was designed for voice and has narrow bandwidth by nature; the MP3 will preserve every bit of quality the source had.
Do FLV metadata tags carry over?
Basic ID3 tags (title) are set from the FLV's onMetaData block where present. Flash-specific cue points have no MP3 equivalent and are dropped.
My FLV is a several-hour webinar. Will it fit?
Very likely yes. Audio-only output stays modest - an hour of 192 kbps MP3 is about 85 MB. Wave's per-file ceiling is 8 GB regardless.
Does this download YouTube audio?
No. Wave doesn't fetch anything from the network. If you already have a .flv file on disk, this converts it - the download itself is a separate tool.