[Bluez-devel] a2play and Motorola HT820

[Bluez-devel] a2play and Motorola HT820

[Nat Butler]

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Hi,

I tested the bluetooth-alsa software for playing mp3's over a Motorola HT820 
headset.  My Thinkpad X40 laptop is running kernel 2.6.12.5, debian unstable.  
Sco works fine through xmms, though the sound quality is poor.  A2play with 
-n works fine for ~10s, then cuts out.  (It cuts out after ~5s without the 
-n option.)  It usually returns, then cuts out again after a similar period.

Here's the headset info from hcitool:

        BD Address:  00:07:A4:B5:4E:D6
        Device Name: Motorola HT820
        LMP Version: 1.2 (0x2) LMP Subversion: 0x77f
        Manufacturer: Cambridge Silicon Radio (10)
        Features: 0xff 0xff 0x8b 0x78 0x18 0x18 0x00 0x80
                <3-slot packets> <5-slot packets> <encryption> <slot offset> 
                <timing accuracy> <role switch> <hold mode> <sniff mode> 
                <park state> <RSSI> <channel quality> <SCO link> <HV2 packets> 
                <HV3 packets> <u-law log> <A-law log> <CVSD> <paging scheme> 
                <transparent SCO> <broadcast encrypt> <enhanced iscan> 
                <interlaced iscan> <interlaced pscan> <inquiry with RSSI> 
                <AFH cap. slave> <AFH class. slave> <AFH cap. master> 
                <AFH class. master> <extended features> 

% sudo hciconfig hci0 revision
hci0:   Type: USB
        BD Address: 00:0F:B3:99:A4:0D ACL MTU: 192:8 SCO MTU: 64:8
        Build 546
        Chip version: BlueCore02-External
        Max key size: 128 bit
        SCO mapping:  HCI

Here's the a2play output:

% mpg123 --au - /home/nrbutler/takemeout.mp3 | ./a2play  -n  00:07:A4:B5:4E:D6
High Performance MPEG 1.0/2.0/2.5 Audio Player for Layer 1, 2 and 3.
Version 0.59r (1999/Jun/15). Written and copyrights by Michael Hipp.
Uses code from various people. See 'README' for more!
THIS SOFTWARE COMES WITH ABSOLUTELY NO WARRANTY! USE AT YOUR OWN RISK!
Title  : Take Me Out                     Artist: Franz Ferdinand
Album  :                                 Year  :     
Comment:                                 Genre : Other

Directory: /home/nrbutler/
Playing MPEG stream from takemeout.mp3 ...
Junk at the beginning 49443303
MPEG 1.0 layer III, 160 kbit/s, 44100 Hz joint-stereo
subbands = 8 blocks = 16 bitpool = 32

len=2048
Header size=32
Sample Rate:44100
Channels:2
Using address: 00:07:A4:B5:4E:D6
Found A2DP Sink

Found A2DP Sink at the destination
Connected [imtu 672, omtu 672, flush_to 65535]

Sent the Stream End Point Discovery Command
Got a Stream End Point Discovery Response
received 1 capabilities

SEID = 1
Requested Capabilities for SEID = 1
Got capabilities response
Sent set configurations command
Set configurations command accepted
Sent open stream command
Connected [imtu 672, omtu 672, flush_to 65535]
Got open stream confirm
Sent stream start

Attached is the result of an hcidump -X.  I hit Control-C after the 
sound cut out.

-Nat

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Re: [Bluez-devel] a2play and Motorola HT820

[Brad Midgley]

Nat

> I tested the bluetooth-alsa software for playing mp3's over a Motorola HT820 
> headset.  My Thinkpad X40 laptop is running kernel 2.6.12.5, debian unstable.  
> Sco works fine through xmms, though the sound quality is poor.  A2play with 
> -n works fine for ~10s, then cuts out.  (It cuts out after ~5s without the 
> -n option.)  It usually returns, then cuts out again after a similar period.

I am redoing our timing loop with rtc because it is inconsistent between 
different computers.

If you're impatient, try it without the -n flag but modify the "magic" 
number of 87 to different values to find one that works better.

You can try one or two "-t" flags to change the encoder settings.

It looks like the ht820 has csr chips in it which is a good 
sign--they're normally very tolerant of variable timing in the stream.

Brad


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