SD to I2S MP3 file metadata causing issues.

[sugnaigiul]

Hello !

I have recently been tinkering with the basics of this very well made library and have encountered a strange issue.

First of all my setup is an ESP32S3 from Seeed with the "Sense" shield (this is where my SD card is) linked to a pcm5102 via I2S.

The main problem I was having is that some of the mp3 files that were stored on my SD card would play without issue and some other wouldn't and would reset the board any time they where played. Just to be clear, i was getting the mp3 files from some youtube to mp3 websites.
Here is what would usually happen in the serial when one of the "wrong" file would be played :

[D] StreamCopy.h : 100 - copy 1024 bytes
[D] StreamCopy.h : 243 - available: 9013609
[D] StreamCopy.h : 390 - write: 1024
[D] AudioEncoded.h : 187 - EncodedAudioOutput::write: 1024
[D] CodecMP3Helix.h : 112 - virtual size_t audio_tools::MP3DecoderHelix::write(const uint8_t*, size_t): 1024
[D] AudioEncoded.h : 199 - EncodedAudioOutput::write: 1024 -> 1024
[D] StreamCopy.h : 396 - write: 1024 -> 1024
[I] StreamCopy.h : 163 - StreamCopy::copy 1024 -> 1024 -> 1024 bytes - in 1 hops
[D] StreamCopy.h : 100 - copy 1024 bytes
[D] StreamCopy.h : 243 - available: 9012585
[D] StreamCopy.h : 390 - write: 1024
[D] AudioEncoded.h : 187 - EncodedAudioOutput::write: 1024
[D] CodecMP3Helix.h : 112 - virtual size_t audio_tools::MP3DecoderHelix::write(const uint8_t*, size_t): 1024
----RESET SEEMED TO HAPPEN HERE----
ESP-ROM:esp32s3-20210327
Build:Mar 27 2021
rst:0x8 (TG1WDT_SYS_RST),boot:0x29 (SPI_FAST_FLASH_BOOT)
Saved PC:0x4201a707
SPIWP:0xee
mode:DIO, clock div:1
load:0x3fce3818,len:0x109c
...

At first i thought that the issue was coming from the size of the files but i quickly (after a few days) realized that it rather originated from the content of the meta data of the mp3 files.

When i downloaded mp3s from the web some of them would have extra info such as name of artist, album etc while some wouldn't.
The one that were working were only the one without that data :

I then found that i could make any file that previously did not work function by removing its metadata, although not through the windows files property menu (that would make the extra lines disapear in the directory but the file would still not function) but rather by using some random website (i am not sure i am allowed to link it here but its the first one that pops up when you search "remove metadata form mp3").

I thought that this was all great but i still wanted to know if someone could give me some extra infromation so that i can be sure i understand the issue.

Thank you !

[pschatzmann]

MP3 decoders are usually resilient enough that they just ignore data they can not process and I have never had any issues with this so far.

Can you share one of the files that create problems ?
You can maybe also try another mp3 decoder...

If you want to contribute, we can try to extend the existing metadata parser to extract the audio, so that we can feed pure audio to the codec.

[sugnaigiul]

Sure, here are some of the files that i tested (i hosted them on discord CDN because github does not support mp3 uploads 🤦‍♂️) :

File that works straight from the mp3 download :
https://cdn.discordapp.com/attachments/847423308369887245/1300149807498788884/piri.mp3?ex=671fca5d&is=671e78dd&hm=b9d10f9a4f15b3c4a8a079ffd7bbfebf767ecd3a6b56b394d59e25dcb7236475&

File that did not work at first :
https://cdn.discordapp.com/attachments/847423308369887245/1300150459570327562/invisibleV1.mp3?ex=671fcaf9&is=671e7979&hm=afb218b328357218fd7a548a16b32ba831a7f6e07b54275e44431590346be9d9&

File that worked after i used a website to remove its metadata :
https://cdn.discordapp.com/attachments/847423308369887245/1300150991693283329/invisibleV2.mp3?ex=671fcb78&is=671e79f8&hm=7670383f55d9155f5bf27493a61e8d1ff9af31fa066c6b8e2434e5d03a15e4d0&

[pschatzmann]

This seems to be a little crazy: usually the meta data is just rund 100 to 200 bytes: In your case it seems to be a couple of kbytes!
As a work around you can try to set the copy size in the copier to something which is bigger then the metadata....

[sugnaigiul]

Ohhh i was not familiar with the normal size of the meta data, that makes more sense.
I will look into all of that.
Thanks a lot for your advice and all these tools !

[pschatzmann]

I committed the class MetaDataFilter: You can use this to remove the disturbing metadata.
Just build a chain like this:

#include "AudioTools.h"
#include "AudioTools/AudioCodecs/CodecMP3Helix.h"

I2SStream i2s;                           // Output stream
MP3DecoderHelix mp3;                     // Decoder
EncodedAudioStream decoder(i2s, mp3);    // Decoding stream
MetaDataFilter filter(decoder);          // remove metadata

and copy the data to the filter.
I tested with your file and it works perfectly...

[hash6iron]

Hi again. I just saw this comment, #1842

I try to do it using MetadataFilterDecoder

[hash6iron]

Thanks so much.
You are doing an excellent work with this library.

[hash6iron]

Hello @pschatzmann .

I have used MetadataFilterDecoder but I have observed that some MP3 with Variable bit rate not playing properly, in a concretely moments of playing not ear nothing and later yes. If I left to use MetadaFilterDecoder all is ok.

Do you have what could be the problem?

[pschatzmann]

I am not aware of any issues: please provide some example mp3 which have a problem

[hash6iron]

Yes. Here attached is one of these files. it's VBR mp3. When I apply metadata filtering, near of the begining of file the playing is not properly.
Thanks in advance
2. Horsell common y el rayo de fuego.mp3.zip

[pschatzmann]

Are you sure that you just give the decoder not enough buffers with this insane bitrate ?

[hash6iron]

The mp3 playing very good without metadatafilter. But if I apply metadatafilter not playing good. But I'm going to try with other buffer size, currently is sized at 4096 bytes.

[hash6iron]

I have tried with 40KB, 80KB, 256KB, 512KB and the problem continue, always in the same position of playing (for each one of the mp3's)

[pschatzmann]

The MetaDataFilterDecoder did not forward the output, so helix did not know where to send the decoded output.
I also added this class to the common functionality, so that no separate include is necessary.

These corrections have been committed

[hash6iron]

Is necessary do any modification or is transparent to my own code?

[hash6iron]

I have updated the library and now works very good. Thanks so much.