How to apply effetcs to a mp3 stream?

[KatePimbleton]

Hi,

I followed the exemple on how to apply effects to any stream, though
I can't find a way to apply it on a mp3 read from a sdCard. Is it implemented
yet?

Thank you

[pschatzmann]

Sure, you would just decode the mp3 first, how to do this is described in the documentation

[KatePimbleton]

I'm able to decode the mp3, following the documentation, then I tried to apply an effect to the AudioPlayer:

MP3DecoderHelix decoder;
AudioPlayer player(source, kit, decoder);
AudioEffectStream effects(player);

And it seems I'm totally wrong...

[KatePimbleton]

following the example: " streams-audiokit-effects-audiokit" I tried to add effects to the "player-sd-audiokit" exemple.
With no luck, any help welcome!

this is what I came up with so far:

#include "AudioTools.h"
#include "AudioLibs/AudioKit.h"
#include "AudioLibs/AudioSourceSD.h" // or AudioSourceIdxSD.h
#include "AudioCodecs/CodecMP3Helix.h"

const int sample_rate = 44100;
const char startFilePath = "/";
const char ext = "mp3";

Delay del(0, sample_rate);

AudioSourceSD source(startFilePath, ext, PIN_AUDIO_KIT_SD_CARD_CS);
AudioKitStream kit;
MP3DecoderHelix decoder; // or change to MP3DecoderMAD
AudioPlayer player(source, kit, decoder);

AudioEffectStream effects(kit);
StreamCopy copier(kit, effects);

void updateValues() {
// update values in controls
del.setActive(1);
del.setDepth(1);
del.setFeedback(0.9);
del.setDuration(1000);
}
void setup() {
Serial.begin(115200);
AudioLogger::instance().begin(Serial, AudioLogger::Info);

// setup output
auto cfg = kit.defaultConfig(TX_MODE);
cfg.sd_active = true;
kit.begin(cfg);

effects.addEffect(del);
effects.begin(cfg);
updateValues();

// setup player
player.setVolume(0.7);
player.begin();

}
void loop() {
copier.copy();
player.copy();
kit.processActions();
}

Cheers

[pschatzmann]

You got the processing chain completly wrong: if you want to use the AudioPlayer, you just send the output the the effects instead of the kit. No further data copy is necessary! : AudioPlayer player(source, effects, decoder);

[KatePimbleton]

Thank you! It worked, the audio is stuttering though.
Is there something else I'm missing ?

I'm playing mp3 files @ 224kb/s
I use the ESP32-audiokit "type 5" ,

here is the code used:

#include "AudioTools.h"
#include "AudioLibs/AudioKit.h"
#include "AudioLibs/AudioSourceSD.h" // or AudioSourceIdxSD.h
#include "AudioCodecs/CodecMP3Helix.h"

const int sample_rate = 44100;
const char startFilePath = "/";
const char ext = "mp3";

Delay del(0, sample_rate);

AudioSourceSD source(startFilePath, ext, PIN_AUDIO_KIT_SD_CARD_CS);
AudioKitStream kit;
MP3DecoderHelix decoder; // or change to MP3DecoderMAD
AudioEffectStream effects(kit);
AudioPlayer player(source, effects, decoder);

void updateValues() {
// update values in controls
del.setActive(1);
del.setDepth(0.5);
del.setFeedback(0.5);
del.setDuration(500);
}
void setup() {
Serial.begin(115200);
AudioLogger::instance().begin(Serial, AudioLogger::Info);

// setup output
auto cfg = kit.defaultConfig(TX_MODE);
cfg.sd_active = true;
kit.begin(cfg);
effects.addEffect(del);
effects.begin(cfg);
updateValues();
// setup player
player.setVolume(1);
player.begin();
}
void loop() {
player.copy();
kit.processActions();
}

[pschatzmann]

Did you try to set the log level to warning ?

[KatePimbleton]

I set it to warning, once in a while this message appears:

"[W] AudioPlayer.h : 445 - -> timeout - moving by 1"

[pschatzmann]

Updated the code to change this to a Info message instead of a warning. It just indicated that the file has finished and it's moving to the next file now...

[KatePimbleton]

Hi,

I tried applying effects on a short "wav" file ( 16BIT 44100hz )
instead of mp3, the result is the same, very loud crakling.
I also tested on a "type 7" board, with no luck.

Any clue about what parameter I could try to tweak ?

code used:

#include "AudioTools.h"
#include "AudioLibs/AudioKit.h"
#include "AudioLibs/AudioSourceSD.h" // or AudioSourceIdxSD.h
#include "AudioCodecs/CodecWAV.h"

const char startFilePath = "/";
const char ext = "wav";
const int sample_rate = 44100;

Delay del(0, sample_rate);

AudioSourceSD source(startFilePath, ext, PIN_AUDIO_KIT_SD_CARD_CS);
AudioKitStream kit;
WAVDecoder decoder;
AudioEffectStream effects(kit);
AudioPlayer player(source, effects, decoder);

void updateValues() {
del.setActive(1);
del.setDepth(0.5);
del.setFeedback(0.5);
del.setDuration(500);
}
void setup() {
// Serial.begin(115200);
AudioLogger::instance().begin(Serial, AudioLogger::Warning);

// setup output
auto cfg = kit.defaultConfig(TX_MODE);
cfg.sd_active = true;
kit.begin(cfg);
kit.setVolume(100);

effects.addEffect(del);
effects.begin(cfg);
updateValues();
// setup player
player.setVolume(0.7);
player.begin();
}
void loop() {
player.copy();
kit.processActions();
}

[pschatzmann]

Not sure, where this could come from.

• Did you try some other effects ?
• Did you try to Comment out the processActions()

[KatePimbleton]

I Tried with "distortion" with and commented out "processActions()",
I still hear loud artifacts.

When I apply effects on a microphone stream it works well.

[KatePimbleton]

I configure channel/sample.rate in the setup :

cfg.channels = 1;
cfg.sample_rate = 44100;

and the artifacts disappeared.