mp2enc(1)

✨ mp2enc — the manual page, but make it make sense ✨

okay bestie, sit down, grab a boba, because today we're learning about mp2enc, a lil audio encoder from the MJPEG tools fam. it's giving "vintage but functional", and honestly? we love her for it. 🎀

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💖 NAME 💖

mp2enc — a simple MPEG-1 layer-II audio encoder. that's it, that's the name, she's lowkey humble about it. ✨

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🌸 SYNOPSIS 🌸

mp2enc [-v num] [-b bitrate_kbps] [-r output_sampling_rate_hz] [-R
rate,chans,bits] [-s ] [-m ] [-e ] [-V ] [-?]  -o output_filename

that's the whole vibe check right there. one line, so many letters. 🦋

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🌈 DESCRIPTION 🌈

so mp2enc is a simple MPEG-1 layer-I/II audio encoder. and when we say "simple", we mean it — she's literally a very mildly warmed over version of the MPEG Software Simulation Group's reference encoder. like, the reference encoder's glow-up was a nap and a new hoodie, no cap. 💅

she takes a WAV file (or a stream on stdin) and outputs a layer-I/II elementary audio stream. she's included in mjpegtools(1) mainly for reasons of completeness, and also because she can do sampling rate conversion — which is genuinely her party trick, periodt. ✨

bestie heads up: if you want a faster (and probably higher quality) layer II encoder, the manual itself says go use toolame(1) instead, which you can grab from: text http://www.planckenergy.com not me telling you to cheat on her, but the docs said it first 🙈

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👑 GENERAL FUNCTION LETTERS 👑

💫 -o output_filename

Specifies the name for the output file.

and here's the cute part: an integer format code (like %d) inside the name gets replaced with the number of the file generated — see printf(3) for how that whole thing works. 🧚

💫 -v num

Set verbosity level to num. the scale is:

• 0 — warnings and errors only (she's quiet, she's mysterious)
• 1 — information as well
• 2 — really verbose (she will not stop talking, and honestly? relatable)

💫 -?

Display a synopsis of the command syntax. a little cheat sheet, a lil reminder, we love a self-aware icon. 💅

💫 -R rate,chans,bits

Indicate that the input is raw PCM without header. this one's a three-number situation, you must specify all three:

• rate — the samplerate in Hz
• chans — the number of channels, which is 1 or 2
• bits — the number of bits per sample

and the tea on bits: 8 bits are unsigned, 16 bits are signed, and both are in machine native byte order. no cap, that detail matters. ⭐

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🦋 FUNCTION LETTERS CONTROLLING OUTPUT STREAM STRUCTURE 🦋

💅 -b bitrate

This sets the bit-rate of the output stream in kBit/sec.

typical values for layer II might be:

• 224kbps — good-quality audio, suitable for capturing Dolby pro-logic signals
• 192kbps or 128kbps — reasonable for low quality audio (e.g. mono TV audio)

and fr fr, if you want really high compression, the manual says that's, of course, better achieved using MPEG-1 layer III ("MP3") audio encoding or AAC. a more appropriate value for layer I might be 384kbps. she contains multitudes. ✨

💅 -r sampling_rate

Sets the audio sampling rate of the reconstructed output signal in Hz.

legal values are exactly: 32000, 44100 and 48000 Hz. and if the input doesn't match? mp2enc will automatically sample-rate convert the input signal if necessary. she's proactive like that. 💖

💅 -l layer

Sets the audio layer. legal values are 1 and 2. the default is layer II. 🎀

💅 -s

Force stereo output. a mono input signal gets channel doubled before encoding, so it becomes stereo. this is useful for players which simply can't handle a non-stereo signal. (yes, those players exist. we don't judge them, we accommodate them. 🫶)

💅 -m

Force mono output. a stereo input signal gets down-mixed before encoding. useful if you've captured a mono signal in stereo and your player can handle mono MPEG-1 Layer 2 audio. 😭 the duality of audio.

💅 -e

Use CRC error protection. that's it. tiny flag, big responsibility. 🔥

💅 -V

Force VCD compatible output. the primary effect of this is to make certain that the sampling rate is set to 44100 — which is to say, -r 44100. 😌

the VCD2.0 specifications permit:

• mono audio at 64, 96 and 192 kbits/sec
• stereo at 128, 192, 224, and 384 kbits/sec

using -V checks that the bitrate is valid for the number of channels. the defaults (unless -m or -b are used) are stereo at 224 kbits/sec. slay. ✨

💅 -o outputpathname

The name of the output file to generate. and here's the spicy bit: if - is given as the pathname, output is written to standard output. yes bestie, dash means stdout. iykyk. 🦋

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💀 BUGS 💀

Mono output does not work for layer I.

that's it. that's the whole bug. she's honest about her flaws, which is main character energy ngl. 🙈

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🧚 AUTHOR 🧚

this man page was written by Andrew Stevens. 💜

if you have questions, remarks, problems or you just want to contact the developers, the main mailing list for the MJPEG-tools is:

mjpeg-users@lists.sourceforge.net

for more info, see our website at:

http://mjpeg.sourceforge.net

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🌟 SEE ALSO 🌟

• mpeg2enc(1)
• mp2enc(1)
• lavrec(1)
• lavplay(1)
• lav2yuv(1)
• lav2wav(1)
• yuvscaler(1)

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and that's the whole page, bestie!! 🫶 this lil icon was brought to you by the MJPEG Tools Team, dated 2 June 2001. go forth and encode responsibly. 💖✨🎀🦋🌸💅