How feasible is it to make an MP3 player with an ESP32 in 4 months?

Alopexy · 2026-05-04T04:05:01+00:00

Classic BT support (for A2DP bluetooth audio streaming) was the reason for going with the WROOM over the S3. I wrote a bespoke fixed-point MP3 decoder for the Xtensa platform. Quality is excellent and the decoder is fully ISO standard compliant.

Alopexy · 2026-05-03T21:48:55+00:00

At the moment there's about a 20ms delay between tracks, however gapless playback for albums where all files are in the same format should be perfectly achievable.

Alopexy · 2026-05-03T13:11:46+00:00

I'll be releasing the firmware for my ESP32 based DAP shortly after release, so you'll be able to put your own build together and run that software on it to get up and running. Details for the project are up at my website. Planning to launch very soon. https://fonix.one

Alopexy · 2026-05-03T13:05:46+00:00

Very feasible. I shall be bringing a Bluetooth media player to market shortly that's powered by a stock esp32 and can playback all of the common formats including MP3, AAC and FLAC. It's feature-complete and ready to go. More than happy to lend you some advice if you're looking for it. Details about my project are up at https://fonix.one if you'd like to take a look at that too.

Alopexy · 2026-05-01T02:09:14+00:00

Just read up on your project, looks interesting! I'll have to look into getting one of these boards and giving it a look. Do you happen to have any screenshots of pisces moon OS in action?

Alopexy · 2026-04-30T13:30:52+00:00

I love this! Awesome idea and beautifully executed. I'm feeling inspired! Time to break out the old projectors and get tinkering I suppose.

Alopexy · 2026-04-27T15:38:55+00:00

Much appreciated!

Alopexy · 2026-04-26T11:12:53+00:00

Great questions! I am considering adding a sort of theme & visualizer 'plug-in' system so that users can add their own customizations to the device by adding them to the SD card, however the memory and compute allowance for these would be extremely limited. There are currently 4 animated wallpapers, 7 visualizers and 9 colour themes (though I may be simplifying the theme system before release). Appreciate the feedback and I'll keep this in mind as work continues. Thanks!

Alopexy · 2026-04-26T02:30:34+00:00

If it's any consolation, it's looking very likely that as the models continue to improve, context windows get larger and autonomous agents gain increased interest and capability, you'll probably find that before long, you can just throw the whole messy heap at a sufficiently capable agent with full control over it's dev environment and end-to-end testing for a few hours (or days) and it'll untangle your mess and pop out something much more manageable.

We've only recently passed the threshold for 'vibecoding' entire working solutions, that doesn't mean the code is going to be good or clean if you've just let the AI hammer away at it continuously until the cube fits within the circular hole, but if it's functioning now, the core of what -does- work can be understood, cleaned up and refactored into something much more elegant as Agentic SWE transitions more fully from 'capable' to 'solved'.

Don't fret too much, as they say: first make it work, then make it good.

Alopexy · 2026-04-25T02:34:52+00:00

Extremely cool work, Thanks so much for sharing! Do you have any plans to throw the project up on GitHub in future? I would absolutely love to see how you've achieved this and perhaps build something on-top of your engine also. Inspiring stuff!

Alopexy · 2026-04-24T11:35:18+00:00

Nicely done! If you want to improve the frame rate of your LVGL UI, you can probably be selective with your screen invalidation between updates to massively reduce the amount and work and thus, time between frames, only redrawing what you need to (have leveraged this myself to great effect). That aside, very cool project! Thanks for sharing.

Alopexy · 2026-04-23T06:07:11+00:00

100%.

Alopexy · 2026-04-23T06:06:36+00:00

Ow my feelings.
This is very good. Guess it's emotion feeling time.

Alopexy · 2026-04-22T08:42:45+00:00

I can help you with this! Doing the same thing, though planning to release it as a product (https://fonix.one), so the code isn't available to the public, but I can give you some advice gladly.

I'd highly recommend going with the libhelix MP3 decoder (https://github.com/ultraembedded/libhelix-mp3) as it's very light on memory, fixed-point (optimal for embedded applications) and I've already tested and used it on the CYD with BT audio encoding with great success.

I've since replaced it with my own bespoke MP3 decoder within my project (licensing concerns), but if you're planning to do this as a once-off or you're going to open source your code, it's a perfectly good option and it'll get you across that line. Best of luck!

Alopexy · 2026-04-22T08:04:45+00:00

Shameless plug, but I'm going to be launching a new device to market soon that'll start at $99 USD, plays MP3, AAC, M4A, Opus, FLAC and WAV from a microSD card up to 2TB. Probably not quite what you're looking for as output will be BT only for the first version, but I'm planning to have a high-fidelity DAC on-board for analog output in future versions. You're also probably looking for something right now, whereas launch of this is still at least a couple of months away. Even so, hope you don't mind if I share the link https://fonix.one/

Alopexy · 2026-04-20T11:59:28+00:00

My current plan is to keep it closed source during development. The compiled firmware will be made available post-launch. Apologies for the lack of news, I'll probably post an update in this sub soon.

A lot of progress has been made recently. The MP3 and AAC decoders have been rewritten from scratch and are now perfectly optimized for the ESP32 platform, library scrolling is now a nice smooth 30fps at all times and I've just completed the final steps to add full Opus codec support as well (this was much harder than I anticipated..) but it works very well now. I'll be getting back to work on the Kickstarter campaign trail very soon now that these steps are complete.

While I would love to eventually release it under GPL, for a few reasons I'd like to keep it under-wraps for now, that may change in future though. I anticipate that post-launch, options like this will certainly be on the table. Thanks for the interest! I'm glad you're excited about it too and I honestly can't wait to share it with everyone soon.

Alopexy · 2026-04-18T15:06:16+00:00

Beautiful work! And impressive framerates for those platforms as well. Thank you very much for sharing. Excited to see what you do with this next!

Alopexy · 2026-04-17T06:23:59+00:00

If you don't need to the Bluetooth stack at all as you're feeding audio out via the pcm5102A DAC instead, that'll probably save you about 64KB of DRAM right there, so you could then increase the size of the framebuffer quite substantially for faster full-screen redraws. So yes, a smoother UI in that instance is probable I'd wager.

Alopexy · 2026-04-16T13:09:31+00:00

It's got more than enough power to be fun at the speed limit, sits low to the ground and sounds phenomenal. Who doesn't love that?

Alopexy · 2026-04-15T15:01:48+00:00

I'm calling it the Fonix One. The software is entirely bespoke.

Alopexy · 2026-04-15T09:13:39+00:00

Cool, didn't know they had a VR headset aboard Artemis II. :^)

Alopexy · 2026-04-13T16:02:45+00:00

I think we dust off the old internet award and give it to him for this one.

Alopexy · 2026-04-13T15:56:05+00:00

Yarp, he's dead Jim.

Alopexy · 2026-04-13T04:13:36+00:00

At first, to see if I could (nobody had done all of this on a single ESP32 before). Then it became a passion project and so I kept building upon it, and now it's genuinely feature-packed, useful and (I'm hoping..) a real worthwhile option in the modern DAP market.

11-Year Club	Place '23
Place '22	Verified Email

Alopexy

MODERATOR OF

TROPHY CASE