Play/Pause event in A2DP source mode

[tueddy]

Hi,

i have a connected a kids headphone and can play audio from SD successfully. This is my minimal sample:
https://github.com/tueddy/BTSourceSD.git

Now the headphone has a button for play/pause. Is it possible to get an event so that i can react on it for pausing/playing audio?
I know the other way around using BT-sink and AVRC events which work fine. I wonder if AVRC events for BT-sink only?

Found nothing about in wiki/issues
Thanks in advance
Dirk

[pschatzmann]

Just set the log level to debug to see what method gets called when you trigger the events and then you can create your subclass and overwrite the method as explained in https://github.com/pschatzmann/ESP32-A2DP/wiki/Design-Overview

[tueddy]

Hi,

i have enabled the verbose level but cannot see any event that track the play/pause button on the BT-headset. Tried with Arduino 2.0.4 / PlatformIO package 5.1.1.

This is my log:

[ 9988][D][BluetoothA2DPSource.cpp:455] bt_app_gap_callback(): [BT_AV] bt_app_gap_callback evt 13
[ 9989][I][BluetoothA2DPSource.cpp:519] bt_app_gap_callback(): [BT_AV] ESP_BT_GAP_MODE_CHG_EVT mode:2
[ 11215][D][BluetoothA2DPSource.cpp:250] bt_app_work_dispatch(): [BT_API] bt_app_work_dispatch event 0xff00, param len 0
[ 11215][D][BluetoothA2DPSource.cpp:301] bt_app_task_handler(): [BT_API] bt_app_task_handler, sig 0x1, 0xff00
[ 11224][I][BluetoothA2DPSource.cpp:628] bt_app_av_sm_hdlr(): [BT_AV] bt_app_av_sm_hdlr state 5, evt 0xff00
[ 11233][D][BluetoothA2DPSource.cpp:596] process_user_state_callbacks(): [BT_AV] process_user_state_callbacks
[ 11243][D][BluetoothA2DPSource.cpp:730] bt_app_av_state_connected(): [BT_AV] bt_app_av_state_connected evt 65280
[ 11253][D][BluetoothA2DPSource.cpp:790] bt_app_av_media_proc(): [BT_AV] bt_app_av_media_proc evt 65280
[ 11262][I][BluetoothA2DPSource.cpp:795] bt_app_av_media_proc(): [BT_AV] a2dp media ready checking ...
[ 11271][D][BluetoothA2DPSource.cpp:250] bt_app_work_dispatch(): [BT_API] bt_app_work_dispatch event 0x3, param len 16
[ 11282][D][BluetoothA2DPSource.cpp:301] bt_app_task_handler(): [BT_API] bt_app_task_handler, sig 0x1, 0x3
[ 11291][I][BluetoothA2DPSource.cpp:628] bt_app_av_sm_hdlr(): [BT_AV] bt_app_av_sm_hdlr state 5, evt 0x3
[ 11300][D][BluetoothA2DPSource.cpp:596] process_user_state_callbacks(): [BT_AV] process_user_state_callbacks
[ 11310][D][BluetoothA2DPSource.cpp:730] bt_app_av_state_connected(): [BT_AV] bt_app_av_state_connected evt 3
[ 11319][D][BluetoothA2DPSource.cpp:790] bt_app_av_media_proc(): [BT_AV] bt_app_av_media_proc evt 3
[ 11328][I][BluetoothA2DPSource.cpp:801] bt_app_av_media_proc(): [BT_AV] a2dp media ready, starting ...
[ 11444][D][BluetoothA2DPSource.cpp:455] bt_app_gap_callback(): [BT_AV] bt_app_gap_callback evt 13
[ 11445][I][BluetoothA2DPSource.cpp:519] bt_app_gap_callback(): [BT_AV] ESP_BT_GAP_MODE_CHG_EVT mode:0
[ 11477][D][BluetoothA2DPSource.cpp:250] bt_app_work_dispatch(): [BT_API] bt_app_work_dispatch event 0x3, param len 16
[ 11477][D][BluetoothA2DPSource.cpp:301] bt_app_task_handler(): [BT_API] bt_app_task_handler, sig 0x1, 0x3
[ 11478][D][BluetoothA2DPSource.cpp:250] bt_app_work_dispatch(): [BT_API] bt_app_work_dispatch event 0x1, param len 16
[ 11486][I][BluetoothA2DPSource.cpp:628] bt_app_av_sm_hdlr(): [BT_AV] bt_app_av_sm_hdlr state 5, evt 0x3
[ 11505][D][BluetoothA2DPSource.cpp:596] process_user_state_callbacks(): [BT_AV] process_user_state_callbacks
[ 11515][D][BluetoothA2DPSource.cpp:730] bt_app_av_state_connected(): [BT_AV] bt_app_av_state_connected evt 3
[ 11525][D][BluetoothA2DPSource.cpp:790] bt_app_av_media_proc(): [BT_AV] bt_app_av_media_proc evt 3
[ 11533][I][BluetoothA2DPSource.cpp:813] bt_app_av_media_proc(): [BT_AV] a2dp media start successfully.
[ 11542][D][BluetoothA2DPSource.cpp:301] bt_app_task_handler(): [BT_API] bt_app_task_handler, sig 0x1, 0x1
[ 11552][I][BluetoothA2DPSource.cpp:628] bt_app_av_sm_hdlr(): [BT_AV] bt_app_av_sm_hdlr state 5, evt 0x1
[ 11561][D][BluetoothA2DPSource.cpp:596] process_user_state_callbacks(): [BT_AV] process_user_state_callbacks
[ 11571][D][BluetoothA2DPSource.cpp:615] process_user_state_callbacks(): [BT_AV] process_user_state_callbacks ESP_A2D_AUDIO_STATE_EVT: Started
Bluetooth audio state: Started
[ 11593][D][BluetoothA2DPSource.cpp:730] bt_app_av_state_connected(): [BT_AV] bt_app_av_state_connected evt 1
[ 21215][D][BluetoothA2DPSource.cpp:250] bt_app_work_dispatch(): [BT_API] bt_app_work_dispatch event 0xff00, param len 0
[ 21215][D][BluetoothA2DPSource.cpp:301] bt_app_task_handler(): [BT_API] bt_app_task_handler, sig 0x1, 0xff00
[ 21224][I][BluetoothA2DPSource.cpp:628] bt_app_av_sm_hdlr(): [BT_AV] bt_app_av_sm_hdlr state 5, evt 0xff00
[ 21234][D][BluetoothA2DPSource.cpp:596] process_user_state_callbacks(): [BT_AV] process_user_state_callbacks
[ 21243][D][BluetoothA2DPSource.cpp:730] bt_app_av_state_connected(): [BT_AV] bt_app_av_state_connected evt 65280
[ 21253][D][BluetoothA2DPSource.cpp:790] bt_app_av_media_proc(): [BT_AV] bt_app_av_media_proc evt 65280
[ 31215][D][BluetoothA2DPSource.cpp:250] bt_app_work_dispatch(): [BT_API] bt_app_work_dispatch event 0xff00, param len 0
[ 31215][D][BluetoothA2DPSource.cpp:301] bt_app_task_handler(): [BT_API] bt_app_task_handler, sig 0x1, 0xff00
[ 31224][I][BluetoothA2DPSource.cpp:628] bt_app_av_sm_hdlr(): [BT_AV] bt_app_av_sm_hdlr state 5, evt 0xff00
[ 31234][D][BluetoothA2DPSource.cpp:596] process_user_state_callbacks(): [BT_AV] process_user_state_callbacks
[ 31243][D][BluetoothA2DPSource.cpp:730] bt_app_av_state_connected(): [BT_AV] bt_app_av_state_connected evt 65280
[ 31253][D][BluetoothA2DPSource.cpp:790] bt_app_av_media_proc(): [BT_AV] bt_app_av_media_proc evt 65280

After reading the docs i have to react on ESP_AVRC_RN_PLAY_STATUS_CHANGE.
ESP_AVRC_RN_VOLUME_CHANGE seems to work fine in same way. Am i miss something?

I think almost every bt-source device has a volume control an at least at start/pause button as my kids headset.
Any idea how to go on? Thank's & best regards
Dirk

[pschatzmann]

I guess you also need to overwrite the bt_av_hdl_stack_evt to activate some more events:

esp_avrc_rn_evt_bit_mask_operation(ESP_AVRC_BIT_MASK_OP_SET, &evt_set, ESP_AVRC_RN_VOLUME_CHANGE|ESP_AVRC_RN_PLAY_STATUS_CHANGE);

After this you should be notified ...

[sfields-forever]

I have overwritten the bt_av_hdl_stack_evt by substituting
esp_avrc_rn_evt_bit_mask_operation(ESP_AVRC_BIT_MASK_OP_SET, &evt_set, ESP_AVRC_RN_VOLUME_CHANGE);
by
esp_avrc_rn_evt_bit_mask_operation(ESP_AVRC_BIT_MASK_OP_SET, &evt_set, ESP_AVRC_RN_VOLUME_CHANGE|ESP_AVRC_RN_PLAY_STATUS_CHANGE);
but I get the error
invalid conversion from 'int' to 'esp_avrc_rn_event_ids_t'

What did I do wrong?

Error in more detail:

lib/ESP32-A2DP/src/BluetoothA2DPSource.cpp: In member function 'virtual void BluetoothA2DPSource::bt_av_hdl_stack_evt(uint16_t, void*)':
lib/ESP32-A2DP/src/BluetoothA2DPSource.cpp:581:65: error: invalid conversion from 'int' to 'esp_avrc_rn_event_ids_t' [-fpermissive]
                                        ESP_AVRC_RN_VOLUME_CHANGE|ESP_AVRC_RN_PLAY_STATUS_CHANGE);
                                        ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from lib/ESP32-A2DP/src/BluetoothA2DPCommon.h:58,
                 from lib/ESP32-A2DP/src/BluetoothA2DPSource.h:22,
                 from lib/ESP32-A2DP/src/BluetoothA2DPSource.cpp:16:
/home/usb/.platformio/packages/framework-espidf/components/bt/host/bluedroid/api/include/api/esp_avrc_api.h:717:65: note:   initializing argument 3 of 'bool esp_avrc_rn_evt_bit_mask_operation(esp_avrc_bit_mask_op_t, esp_avrc_rn_evt_cap_mask_t*, esp_avrc_rn_event_ids_t)'
                                         esp_avrc_rn_event_ids_t event_id);
                                         ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~

[pschatzmann]

You forgot to cast!

[sfields-forever]

Thankyou. I now have replaced
esp_avrc_rn_evt_bit_mask_operation(ESP_AVRC_BIT_MASK_OP_SET, &evt_set, ESP_AVRC_RN_VOLUME_CHANGE);
by
esp_avrc_rn_evt_bit_mask_operation(ESP_AVRC_BIT_MASK_OP_SET, &evt_set, (esp_avrc_rn_event_ids_t)(ESP_AVRC_RN_VOLUME_CHANGE | ESP_AVRC_RN_PLAY_STATUS_CHANGE));
and it compiles.
The log level is set to verbose/debug in addition. But I am not notified when I click on the bt-headphone play/pause/... I get only the sort of messages, @tueddy reports here.
What am I missing? Has anyone managed to be notified by play/pause events?

[ChadMatsalla]

Hi Phil!

I created a subclass and I'm trying to detect any AVRC event whatsoever. I see nothing. I've tried two devices and no change (including volume) is ever detected.

Could you give any hint as to the best place and method to log any AVRC event?

I see that you call esp_avrc_ct_init, then you register the callback esp_avrc_ct_register_callback(ccall_bt_app_rc_ct_cb);. I'm confused as to why esp_avrc_ct_register_callback(ccall_bt_app_rc_ct_cb) then apparently delegates to bt_app_rc_ct_cb. Am I correct that this line in bt_app_rc_ct_cb should log any event?

851     ESP_LOGD(BT_RC_CT_TAG, "%s evt %d", __func__, event);

If that's not the place, where would be the best place to catch any event?

Thank you,

Chad

[jamesbaber]

Should the ESP_AVRC_RN_VOLUME_CHANGE notifications be logged in debug mode?
I've got ESP IDF version 4.4 but don't get any of the volume change logs I think bt_av_notify_evt_handler should provide.

[pschatzmann]

Do you have a bluetooth speaker with volume buttons ?
You should get the notifications when you change the volume on your bluetooth speaker.

[ChadMatsalla]

I'm sorry but I shelved this project. I was trying to turn a bluetooth remote into a general-purpose remote. It was for a lie-detector for my son's 7-th grade class. A kid would sit at it and Alex would decide whether the kid was lying and trigger the correct light by pressing one of the buttons. At the moment I no longer have use for such a thing.

[jamesbaber]

Thanks Chad. That sounds like it would have been a fun project!

Phil, I've taken audio-tools' streams-generator-a2dp.ino, changed the log level to Debug or Info but when I change the volume on my Sony WH-1000XM4s I do not get any additional serial logs.
out.source().get_volume() does report a changing volume value which is great. But no messages. I've just updated my audio-tools and esp32-a2dp libraries. I suppose this gives me something to work on.

Thanks!

[jamesbaber]

I've found part of my issue. I was setting the AudioLogger log level to Debug, instead of the ESP32 core debug level. I do now get headphone volume level changes showing up in the logs.

[pschatzmann]

Just set the log level to Debug and trigger some commands and you should be able to see what methods are called.
I would expect that it is av_hdl_stack_evt

[franzSusemichel]

Hi,

i have a connected a kids headphone and can play audio from SD successfully. This is my minimal sample: https://github.com/tueddy/BTSourceSD.git

Now the headphone has a button for play/pause. Is it possible to get an event so that i can react on it for pausing/playing audio? I know the other way around using BT-sink and AVRC events which work fine. I wonder if AVRC events for BT-sink only?

Found nothing about in wiki/issues Thanks in advance Dirk

Hi,

not sure if i have the same question, but i'm using a teensy to send start/stop which works fine for me. Unfortunatley i don't have information if play/pause is toggled on my mobile phone (want to show that information on teensy)

Any recommendations?