Audio with ESP32

Other Hardware Audio
1

Hi all, I am using an ESP32 to create a mini-TV based on this project. I notice that the author is using the built in DSP in the ESP32, where other projects use an external DAC like this one. He's also using .MP3 audio, where some go for AAC.

I'm trying to figure out what is the best/most efficient mthod here to play the audio. I'm using a 320x 240 display and audio is coming to a halt with lots of jitter and noise and I am losing frames. When I crank back the frame rate I can get the audio acceptable.

Just checking in to see if anyone has any ideas on how to improve the overall video/audio experience.

2

It depends on your application, I've used,

  1. An i2s DAC
  2. A combined i2s dac and amp (similar to the one you linked)
  3. The onboard 8-bit DAC
  4. PWM (you can do 10-bit PWM on ESP32 with a frequency of ~78 KHz)
  5. Pulse density modulated audio.

If you ar losing frames it sounds like you're pushing the ESP32 too much (or something is not very efficient). I glanced at the project. Seems cool but complicated.

If I were trying to balance quality and efficiency I would go for the I2S DAC or combined I2S DAC and amp if you are ok with the quality from the linked amp. I've used something similar in a small Bluetooth speaker. It's fine but not a fantastic quality amp.

3

Thanks so much for the reply - I'll try with the i2S DAC - I have it working with the onboard DSP once I crank down the frame rate on the video, so I assume the i2s DAC will work. Fun project that is making me learn a lot of new stuff - I can see why the Raspberry Pi is the go to for video projects :slight_smile:

4

What's interesting is that when I use the internal DAC, with this configuration I get audio:

new AudioOutputI2S(0, 1, 128);

However, using the DAC with the built in Amp, I get a bunch of "clipping":

  out = new AudioOutputI2S(); //This uses an external DAC
  mp3 = new AudioGeneratorMP3();
  out->SetGain(0.3);
  aFile = new AudioFileSourceFS(SD);

Any thoughts?

5

I'm not massively familiar with the audio library. You might have to raise an issue with the author on github.

For specific issues with your project you'll need to show all code to reproduce the problem as well as a schematic.

But Clipping generally means the power supply isn't sufficient. Some esp32s come with an extra regulator that you can power a 1-2 ish watt speaker with but for more help more details will be required.

1 Like
6

Thanks so much. I'll take your advice on board and investigate those things.

7

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