aplay failed on bluetooth audio with bluez 4.101

Hi Community,

I run into a bluetooth headset issue with bluez 4.101. After a
successful pairing and connection, I failed to play a .wav file
through the bluetooth headset by aplay. I have been searching around
for a couple days and looked at bluez 4.101 source code to ensure the
audio.conf settings make sense but still clueless.

My laptop is Ubuntu 15.04 with bluez 4.101-ubuntu25 (kernel:
3.19.0-25-generic), the target embedded uses yocto "dizzy" release
with bluez 4.101 as well (kernel: 3.4). On both laptop and target
machine the libasound-module-bluez has been installed properly.

My settings are:

1. /etc/bluetooth/main.conf
The default one, in particular, Class=0x00100

2. /etc/bluetooth/audio.conf

    [General]
    Enable=Socket

    [Headset]
    HFP=true
    MaxConnected=1
    FastConnectable=false

    [A2DP]
    SBCSources=1
    SBCSinks=1
    MPEG12Sources=1
    MPEG12Sinks=1

3. ~/.asoundrc
    pcm.btheadset {
        type plug
        slave {
            pcm {
                type bluetooth
                device "1C:48:F9:AD:19:EE"
                profile "auto"
            }
        }

        hint {
            show on
            description "BT Headset"
        }
    }

    ctl.btheadset {
        type bluetooth
    }

where I have hardcoded the bdaddr of my bluetooth headset.

4. My bluetooth headset has been paired and connected successfully:

$ hcitool con
Connections:
    < eSCO 1C:48:F9:AD:19:EE handle 70 state 1 lm MASTER
    < ACL 1C:48:F9:AD:19:EE handle 69 state 1 lm MASTER AUTH ENCRYPT


5. On my laptop, I can play through bluetooth headset with mplayer successfully:

    $ mplayer -ao alsa:device=btheadset /usr/share/sounds/alsa/Front_Center.wav

    MPlayer2 2.0-728-g2c378c7-4 (C) 2000-2012 MPlayer Team
    Cannot open file '/home/harry/.mplayer/input.conf': No such file
or directory
    Failed to open /home/harry/.mplayer/input.conf.
    Cannot open file '/etc/mplayer/input.conf': No such file or directory
    Failed to open /etc/mplayer/input.conf.

    Playing /usr/share/sounds/alsa/Front_Center.wav.
    Detected file format: WAV / WAVE (Waveform Audio) (libavformat)
    [lavf] stream 0: audio (pcm_s16le), -aid 0
    Load subtitles in /usr/share/sounds/alsa/
    Selected audio codec: Uncompressed PCM [pcm]
    AUDIO: 48000 Hz, 1 ch, s16le, 768.0 kbit/100.00% (ratio: 96000->96000)
    AO: [alsa] 8000Hz 1ch s16le (2 bytes per sample)
    Video: no video
    Starting playback...
    A:   1.4 (01.4) of 1.4 (01.4)  0.1%

    Exiting... (End of file)


6. However, on my laptop, play with aplay failed:

    $ aplay -D btheadset /usr/share/sounds/alsa/Front_Center.wav

    Playing WAVE '/usr/share/sounds/alsa/Front_Center.wav' : Signed 16
bit Little Endian, Rate 48000 Hz,         Mono
    ^CAborted by signal Interrupt...

All I got is constant beeeeep noises and I have to press Ctrl^C to terminate it.

7. On my target machine, the rootfs is provided by "dizzy" yocto
release also with bluez 4.101. I have modified main.conf to define
"Class=0x5A020C" (or simply 0x000200) and audio.conf to enable
"SCORouting=PCM".

8. On my target machine, the same aplay command failed as well. But it
doesn't output any sound, no constant beep noise. Only when I
terminated it could I hear a short beep sound.


Given that mplayer works on bluetooth headset, I thought the bridging
from alsa to bluez works. However, why aplay failed? On my target
there is only aplay now and it's difficult to add mplay, so I would
have to make aplay work with bluetooth audio.

Any comments are much appreciated!

Cheers,
Harry


P.S.

The following is the "bluetoothd -d -n" result during "aplay -D btheadset ...":

bluetoothd[9490]: audio/unix.c:server_cb() Accepted new client
connection on unix socket (fd=33)
bluetoothd[9490]: audio/unix.c:client_cb() Audio API: BT_REQUEST <-
BT_GET_CAPABILITIES
bluetoothd[9490]: audio/unix.c:unix_ipc_sendmsg() Audio API:
BT_RESPONSE -> BT_GET_CAPABILITIES
bluetoothd[9490]: audio/unix.c:client_cb() Audio API: BT_REQUEST <- BT_OPEN
bluetoothd[9490]: audio/unix.c:handle_sco_open() open sco - object=ANY
source=ANY destination=1C:48:F9:AD:19:EE lock=write
bluetoothd[9490]: audio/unix.c:unix_ipc_sendmsg() Audio API:
BT_RESPONSE -> BT_OPEN
bluetoothd[9490]: audio/unix.c:client_cb() Audio API: BT_REQUEST <-
BT_SET_CONFIGURATION
bluetoothd[9490]: audio/unix.c:unix_ipc_sendmsg() Audio API:
BT_RESPONSE -> BT_SET_CONFIGURATION
bluetoothd[9490]: audio/unix.c:client_cb() Audio API: BT_REQUEST <-
BT_START_STREAM
bluetoothd[9490]: audio/headset.c:headset_set_state() State changed
/org/bluez/9490/hci1/dev_1C_48_F9_AD_19_EE: HEADSET_STATE_CONNECTED ->
HEADSET_STATE_PLAY_IN_PROGRESS
bluetoothd[9490]: audio/media.c:headset_state_changed()
bluetoothd[9490]: audio/media.c:headset_state_changed()
bluetoothd[9490]: audio/headset.c:sco_connect_cb() SCO socket opened
for headset /org/bluez/9490/hci1/dev_1C_48_F9_AD_19_EE
bluetoothd[9490]: audio/headset.c:sco_connect_cb() SCO fd=35
bluetoothd[9490]: audio/unix.c:unix_ipc_sendmsg() Audio API:
BT_RESPONSE -> BT_START_STREAM
bluetoothd[9490]: audio/unix.c:unix_ipc_sendmsg() Audio API:
BT_INDICATION -> BT_NEW_STREAM
bluetoothd[9490]: audio/headset.c:headset_set_state() State changed
/org/bluez/9490/hci1/dev_1C_48_F9_AD_19_EE:
HEADSET_STATE_PLAY_IN_PROGRESS -> HEADSET_STATE_PLAYING
bluetoothd[9490]: audio/media.c:headset_state_changed()
bluetoothd[9490]: audio/media.c:headset_state_changed()
bluetoothd[9490]: audio/transport.c:media_transport_acquire()
Transport /org/bluez/9490/hci1/dev_1C_48_F9_AD_19_EE/fd0: read lock
acquired
bluetoothd[9490]: audio/transport.c:media_transport_acquire()
Transport /org/bluez/9490/hci1/dev_1C_48_F9_AD_19_EE/fd0: write lock
acquired
bluetoothd[9490]: audio/transport.c:media_owner_create() Owner
created: sender=:1.309 accesstype=rw
bluetoothd[9490]: audio/transport.c:media_transport_release()
Transport /org/bluez/9490/hci1/dev_1C_48_F9_AD_19_EE/fd0: read lock
released
bluetoothd[9490]: audio/transport.c:media_transport_release()
Transport /org/bluez/9490/hci1/dev_1C_48_F9_AD_19_EE/fd0: write lock
released
bluetoothd[9490]: audio/transport.c:media_owner_free() Owner :1.309
bluetoothd[9490]: audio/unix.c:client_cb() Unix client disconnected (fd=33)
bluetoothd[9490]: audio/headset.c:headset_set_state() State changed
/org/bluez/9490/hci1/dev_1C_48_F9_AD_19_EE: HEADSET_STATE_PLAYING ->
HEADSET_STATE_CONNECTED
bluetoothd[9490]: audio/media.c:headset_state_changed()
bluetoothd[9490]: audio/media.c:headset_state_changed()
bluetoothd[9490]: audio/unix.c:client_free() client_free(0x7f59b52e54b0)