Looking for multiDecoder.h example...

[chicodaman]

re: "(February 2025 #1937) New Functionality: -- new class MultiDecoder to support multiple codecs"...will there be any examples of how to best use this, or can anyone show a simple code snippet as to how to implement?

Just discovered these libraries, very impressed and learning a lot...thanks!

[pschatzmann]

Please check the codec wiki documentation

[chicodaman]

Thanks for the response. I've had mixed results with the documentation snippet code.

Using the url in the snippet, the function "determineMime" in "MimeDetector.h" usually returns actual_mime = "audio/mpeg" or "audio/aac" as expected and the stream plays audio, but some urls return actual_mime = "" and the serial output is:

...
13:45:00.843 -> [I] StreamCopy.h : 418 - try write  - 21 (open 1024 bytes) 
13:45:00.844 -> [E] StreamCopy.h : 411 - write  to target has failed after 22 retries! (1024 bytes)
...

Of course, no audio output is generated. But these same urls DO work ok in the audio-tools example sketch "streams-url_aac-i2s.ino".

I'm sure I'm overlooking something due to my limited understanding of the library code. I'll keep plugging away. Thanks for any assistance or advice...

[pschatzmann]

Did you provide the URLStream in the constructor of the MultiDecoder, so that the system can look up the mime type from the http response ?

Do you have an example of an url that does not provide any mime ?

[chicodaman]

Did you provide the URLStream in the constructor of the MultiDecoder, so that the system can look up the mime type from the http response ?

Do you mean changing the "audio/mpeg" parameter to "audio/aac"? All I did was change that and the url in the documentation snippet code. Most urls worked ok, some didn't. Do I need to do something in addition to that?

Do you have an example of an url that does not provide any mime ?

I have several, but they are privately hosted icecast streams which shouldn't be posted publicly for copyright/royalty reasons. Is there a way to send them to you privately (I know github doesn't support private messaging...)

Thanks...

[pschatzmann]

You would use
URLStream url("ssid","password");
MultiDecoder multi(url);

What output do you get when you run curl -v for one of your urls?

[chicodaman]

You would use
URLStream url("ssid","password");

Yes.

MultiDecoder multi(url);

Ah, I see you said in the docs: "You can provide the URLStream in the constructor of the MultiDecoder, so that the system can look up the mime type from the http response."

I just used the form in the code snippet: "MultiDecoder multi;" This worked ok with the url example in the code snippet: url.begin("http://stream.srg-ssr.ch/m/rsj/mp3_128", "audio/mpeg");

What form should MultiDecoder multi(url) take? None of the following compile:
-- MultiDecoder multi("http://stream.srg-ssr.ch/m/rsj/mp3_128");
-- MultiDecoder multi(http://stream.srg-ssr.ch/m/rsj/mp3_128);
-- MultiDecoder multi "http://stream.srg-ssr.ch/m/rsj/mp3_128";
-- MultiDecoder multi http://stream.srg-ssr.ch/m/rsj/mp3_128;
(This is where my ignorance shows :/ Sorry.)

What output do you get when you run curl -v for one of your urls?

All of the urls which fail on the code snippet connect and play ok when entered into a browser (Chrome, Safari).

Curl output (domain name changed to aacstream, ip addr changed to 555.555.555.555):

~ % curl -v http://aacstream.us.to:8000/aacstream
* Host aacstream.us.to:8000 was resolved.
* IPv6: (none)
* IPv4: 555.555.555.555
*   Trying 555.555.555.555:8000...
* Connected to aacstream.us.to (555.555.555.555) port 8000
> GET /aacstream HTTP/1.1
> Host: aacstream.us.to:8000
> User-Agent: curl/8.6.0
> Accept: */*
>
* HTTP 1.0, assume close after body
< HTTP/1.0 200 OK
< Server: Icecast 2.4.4
< Connection: Close
< Date: Thu, 13 Mar 2025 00:04:02 GMT
< Content-Type: audio/aac
< Cache-Control: no-cache, no-store
< Expires: Mon, 26 Jul 1997 05:00:00 GMT
< Pragma: no-cache
< Access-Control-Allow-Origin: *
< icy-br:128
< icy-name:Host Machines's Broadcast: aacstream
< icy-pub:0
<

For your convenience, this is the code snippet from the documentation. As I said, the only changes I made were to the SSID/password and the url:

#include "AudioTools.h"
#include "AudioTools/AudioCodecs/CodecMP3Helix.h"
#include "AudioTools/AudioCodecs/CodecAACHelix.h"
#include "AudioTools/AudioLibs/AudioBoardStream.h"

URLStream url("ssid","password");
I2SStream i2s;
MultiDecoder multi;
MP3DecoderHelix mp3;
AACDecoderHelix aac;
WAVDecoder wav;
EncodedAudioStream dec(&i2s, &multi); // Decoding stream
StreamCopy copier(dec, url); // copy url to decoder


void setup(){
  Serial.begin(115200);
  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Info);  

  // register supported codecs with their mime type
  multi.addDecoder(mp3, "audio/mpeg");
  multi.addDecoder(aac, "audio/aac");
  multi.addDecoder(wav, "audio/vnd.wave");

  // setup i2s
  auto config = i2s.defaultConfig(TX_MODE);
  // you could define e.g your pins and change other settings
  //config.pin_ws = 10;
  //config.pin_bck = 11;
  //config.pin_data = 12;
  //config.mode = I2S_STD_FORMAT;
  i2s.begin(config);

  // setup I2S based on sampling rate provided by decoder
  dec.begin();

// mp3 radio
  url.begin("http://stream.srg-ssr.ch/m/rsj/mp3_128","audio/mpeg");

}

void loop(){
  copier.copy();
}

Thanks for your patience with me on this...

[pschatzmann]

No, it is like I wrote;

#include "AudioTools.h"
#include "AudioTools/AudioCodecs/CodecMP3Helix.h"
#include "AudioTools/AudioCodecs/CodecAACHelix.h"
#include "AudioTools/AudioLibs/AudioBoardStream.h"

URLStream url("ssid","password");
I2SStream i2s;
MultiDecoder multi(url);
MP3DecoderHelix mp3;
AACDecoderHelix aac;
WAVDecoder wav;
EncodedAudioStream dec(&i2s, &multi); // Decoding stream
StreamCopy copier(dec, url); // copy url to decoder

As you can see, the reply of your url provies the expected mime type:

< Content-Type: audio/aac

[chicodaman]

Got it. Sorry for my misunderstanding.

After changing "MultiDecoder multi" to "MultiDecoder multi(url)", all aac and mp3 streams I've tested now select the correct codec and play successfully.

And the second parameter ("audio/mpeg") in the "url.begin" line:

// mp3 radio
  url.begin("http://stream.srg-ssr.ch/m/rsj/mp3_128","audio/mpeg");

can be eliminated:

// mp3 radio
  url.begin("http://stream.srg-ssr.ch/m/rsj/mp3_128);

and all stream urls play correctly.

Cool! Thanks for assistance and the amazing code....