ESP8266 Community Forum

- Mon Jul 06, 2015 1:43 pm #22611

I am very interested in mp3 decoding, but my project needs the encoding part as well, so this kind of solutions only represent a first step. Horacio

Hi Horacio!
thanks for the feedback

It's true the Espressif example only does MP3 decoding, and MP3 encoding in real-time is impractical as its very compute-intensive. However MP3 is just one of many codecs that exist, and if you need to encode and transmit audio, there are codecs that can do that and are "light" enough to run on this module.
For example, there's a range of different "voip" codecs that can do the job, some with pretty decent quality. I have been able to get a demo system with full voip 2-way audio going on a small external Cortex M4 MCU, with support for the full range of standard telephony codecs. I plan to port a subset of that to run directly on the ESP8266 for some derivative uses.
Other codecs may be possible to port as well, such as CSR AptX, and low-latency version.

Can you describe a little more about your project plan , and what is the minimum requirement for audio quality & latency ? is mono sufficient or do you need stereo ?
what is the input and output - mic, speakers? how powerful the speakers?

cheers
Frantz

- Mon Jul 06, 2015 2:10 pm #22615

Hi frob,
Maybe people are simply waiting to see more details about your project.
Will you share schematic and board layout ?
Best wishes into this project !

Hi Martin,
thanks !

honestly haven't thought about that aspect yet, so i don't know at this point - but i will consider it now:)

Since the hope is this will become a commercial module, if there is interest, i would put together a datasheet for it with pin-outs etc and reference schematics for how to embed it in an application. I would probably also do a "demo board" with the usual ports for download / debugging as well as audio interfaces , like line-in, out, s/pdif, mic, amp and speaker out (stereo) .
Normally the demoboard schematic and layout are published with the support package.

For the module itself, i'm not sure there is any real value to individual "makers"
i can probably share the schematics since there is really nothing innovative there, the ram IC & connections are straight out of the Espressif MP3 example description, and the rest are just minor tweaks and resemble any other ESP8266 module;
disclosing the layout as gerber or source files really is more risky, so ill need to think about that more -
I would be happy to allow individuals be able to make one from scratch at home, but
the parts are small and nearly impossible to solder by hand without expensive equipment , so its not likely that any home experimenter would attempt or be successful in that -
but once the gerbers are "out there" its trivially easy for any factory in China to copy them and flood the market with clones at a price i can't compete with (notice there are already dozens of different ESP8266 module's available today from many different vendors, all very cheap)
And since i will be paying the cost and doing all the upfront work on design and coding , FCC cert etc, documentation and support etc., i need some assurance that i can sell enough modules (at a very reasonable price of course) to at least break even, and hopefully pay a few bills with the proceeds...
its a thorny issue, but i'd love to find a happy compromise that is best for the community while still leaving me the possibility to make a buck or 2 from this effort

- Mon Jul 06, 2015 3:02 pm #22621 Hi again Frob,

Yes, I'm pretty sure people will order you some of these modules if they are affordable. I will !
Do you have any pricing target yet ?
As for schematic, and especially gerbers, I understand your point. But you can provide at least the pins breakout (GPIOs) and the specs (ie. : RAM, etc. BTW, is the RAM is hooked-up on SPI ?)

Best wishes,
Martin.

- Mon Jul 06, 2015 7:38 pm #22640 One question: how much $?