16-24 Bit resample and Volume impact ? and VolumeMeter output ?

[Ives-Heymans]

Hi Phil, all
I was playing around with the resample to 48Khz 24 Bit and that works well (scope confirmed 48Khz) but I did notice that on for example max volume 127 with the resample the VolumeMeter outputPercentage is much lower than without the resample. I will check later the real output amplitude on the scope but pretty sure it sounds lower to.
Is the volume based on the original a2dp 16 Bit ? (the functions seem to set the volume on the a2dp_sink) and we do not get to the 24 bit resample level ? Do I need to do a correction somehow ?
Like always fun and learning,
Thx Phil , great work.

[pschatzmann]

Setting the volume for A2DP is always done with 16 bit calculations.

If you report using the VolumeMeter using volumePercent(), volumeRatio() or volumeDB() there should not be any difference but the reported volume() values depend on the bits: the max values for

• 16 bits: 32767
• 24 bits: 8388607
• 32 bits: 2147483647

Make sure that the VolumeMeter is configured correctly with the correct input bits per sample.

Maybe you did something wrong in your sketch ?

[Ives-Heymans]

Hi Phil, That might be it, I configured the VolumeMeter with the output resample configuration 24 Bit not the native A2DP felt more correct so A2DP and the I2S output where the same. Code snippet: // Define streams AudioInfo input_stream_info(44100, 2, 16); AudioInfo output_stream_info(48000, 2, 24); // Define Outputs I2SStream I2Sout; VolumeMeter vuMeter; MultiOutput multiOut; ResampleStream resample_stream(multiOut); BluetoothA2DPSink a2dp_sink(resample_stream); // Add Outputs multiOut.add(vuMeter); multiOut.add(I2Sout); // Setup the resample stream from 44100 Hz (from_info) to 48000 Hz 24 bit resample_stream.begin(input_stream_info, output_stream_info.sample_rate); // Setup I2S Output auto cfg = I2Sout.defaultConfig(); cfg.copyFrom(output_stream_info); cfg.pin_bck = 22; cfg.pin_ws = 25; cfg.pin_data = 21; I2Sout.begin(cfg); vuMeter.begin(output_stream_info); Brgds, Ives Heymans From: Phil Schatzmann ***@***.***> Sent: Wednesday, 30 April, 2025 8:38 AM To: pschatzmann/ESP32-A2DP ***@***.***> Cc: Ives-Heymans ***@***.***>; Author ***@***.***> Subject: Re: [pschatzmann/ESP32-A2DP] 16-24 Bit resample and Volume impact ? and VolumeMeter output ? (Discussion #704) Setting the volume for A2DP is always done with 16 bit calculations. If you report using the VolumeMeter using volumePercent(), volumeRatio() or volumeDB() there should not be any difference but the reported volume() values depend on the bits: the max values for * 16 bits: 32767 * 24 bits: 8388607 * 32 bits: 2147483647 Make sure that the VolumeMeter is configured correctly with the correct input bits per sample. Maybe you did something wrong in your sketch ? - Reply to this email directly, view it on GitHub<#704 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/A2TVDDG3AX27M4XE3LU7RND24BVWDAVCNFSM6AAAAAB4EV4INWVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTEOJYHA4TOMI>. You are receiving this because you authored the thread.Message ID: ***@***.******@***.***>>

[pschatzmann]

Please read the corresponding Wikis: the ResampleStream does not chnage the bits!