Convert MPEG to MP3 - extract audio
Old MPEG-1 and MPEG-2 videos carry MP2 or AC-3 audio inside their Program Streams (see Audio codecs explained for what MP2, AC-3, and MP3 each are). Wave discards the video and re-encodes the audio to a portable 192 kbps MP3 that plays on any device.
What actually changes
MPEG-1 System Streams (.mpg, .mpeg from the VCD era) hold MP2 audio. MPEG-2 Program Streams (from DVDs and the early digital-TV era) hold MP2, AC-3, or LPCM audio. Wave's wasm engine decodes all three locally with no server involved.
Because the video track is discarded entirely, extract runs several times faster than a full MPEG-to-MP4 conversion - an hour of source content typically finishes in under a minute. Wave uses LAME (libmp3lame) at VBR around 190 kbps, which is transparent for any content old enough to be in an MPEG-1 or MPEG-2 file.
MP2 (MPEG-1 Audio Layer 2) preceded MP3 by a few years and remained the dominant audio codec in broadcast radio (DAB / DAB+) and Video CD content long after MP3 took over the consumer download space. It has a natural sample rate range of 32-48 kHz and typical bitrates of 128-384 kbps stereo. The extract path decodes MP2 through ffmpeg-wasm's native mp2 decoder and re-encodes to MP3 through LAME. There is a small quality drop moving between lossy codecs, but at 192 kbps MP3 the result is transparent on almost any playback gear.
AC-3 audio in MPEG-2 sources typically means DVD content. Wave handles the 2-channel stereo case directly and downmixes 5.1 to stereo before MP3 encoding. LPCM audio (uncompressed, common in the highest-quality DVD tracks) decodes trivially and produces the smallest quality drop through the LAME encode - MP3 at 192 kbps preserves what humans can hear on typical playback.
Three steps.
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01
Step 1
Drop the .mpg or .mpeg file onto the card.
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Step 2
Pick MP3 as the output format.
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Step 3
Convert and save the MP3.
Answers, specifically.
Isn't MP2 basically the same as MP3?
They're close cousins - MPEG-1 Audio Layer 2 versus Layer 3 - but not the same bitstream. MP3 players won't decode raw MP2 samples, so a full re-encode is required. At typical source bitrates the audible loss is negligible.
My .mpg is audio-only. Will Wave handle it?
No. Wave requires a video track and rejects audio-only sources up front. If you have an MPEG audio file (usually .mp2 or .mp3), a dedicated audio tool is the right fit.
What about the surround audio on a DVD-sourced MPEG?
Wave downmixes multi-channel AC-3 to stereo before encoding to MP3. MP3 doesn't carry surround audio at all - a downmix is the only path.
Are MPG and MPEG the same file format?
Yes. Different extensions, identical Program Stream container. Wave treats them the same.
How fast is it?
An hour of MPEG audio typically re-encodes in 30-60 seconds on a modern laptop, because Wave never has to decode a single video frame.
DVD-source MPEG - is there a chance the audio comes out with a click at every VOB boundary?
Rarely, but yes on some poorly-authored discs. When a DVD title spans multiple VOBs, some ripping tools produce an MPEG with a small audio glitch at each 1 GB boundary. Wave preserves the source audio exactly; if the glitch is in the source it will be in the MP3. A desktop audio editor can trim it.
Can I extract from Video CD (VCD) MPEG-1 files?
Yes. Video CDs used MPEG-1 with MP2 audio at 224 kbps stereo. Wave handles them the same way as newer MPEG-1 material - decode MP2, re-encode to MP3 at 192 kbps. The audio quality is preserved to the source ceiling, which is respectable but not modern.
Extracting audio from a video game cutscene MPG?
Works fine. Late-90s and early-2000s PC games used MPEG-1 or MPEG-2 for pre-rendered cutscenes and shipped them as .mpg files on the game CD / DVD. Wave extracts the music and dialogue tracks; whether the game protected those files is a legal question separate from the technical one.