Play MP3 from SD card (A2DP) without player

[alfons12]

Hello,

I can successfully play MP3 from the SD card on my Bluetooth speaker using A2DPStream. Then I found it is not recommended to use this class (it is inefficient) so I started to implement it using callback.

But I can't get any sound from the speaker. What am I doing wrong?

This is the source code.
decoder.txt

Thank you.

[pschatzmann]

That's now how things are working: please read the Codec Wiki: Chapter Decoding on the Input Side.
There is no need to copy things!

[alfons12]

What do you mean by "There is no need to copy things" please? How else shall I get the mp3 file from SD to the decoder if not using copier?

[alfons12]

Ok, but please before I dive into studying ... How inefficient is the A2DPStream? Is it worth reimplementing if I need to just play short announcements or 90 seconds song?

[pschatzmann]

If you run low on RAM, you would just activate PSRAM instead and the problem is solved.
You could also try to optimize the buffer_size in the A2DP configuration. I recommend to use 2 x the amount of bytes the decoder provides.

[alfons12]

I don't have a chip with PSRAM unfortunately.

Ok, I will try to finish my product with A2DPStream and only if it starts crashing on RAM I will investigate the wiki as you suggested.

[pschatzmann]

You just specify the File as source in the EncodedAudioStream as described in the Chapter Decoding on the Input Side.
If you are still struggeling, I suggest that you re-read the most important basics Wiki

[alfons12]

Sounds good, but in the provided example I2SStream is used and I can't use A2DPStream..