Issue with FastMixer while playing short tones

[Mohan Kumar]

I seeing issues when I use fastmixer for output while I play short Tones by pressing volume button, The output is having extra zeroes inserted between the actual output which makes glitches in the output.

How can we solve this issue?

[Glenn Kasten]

Please say which SoC, OEM device name/model, Android release version,

and the audio output HAL configuration: number of HAL buffers, frames per buffer,

sample rate in Hz, and frame format (e.g. stereo 16-bit PCM). Also

please include the output of dumpsys media.audio_flinger while you are hearing glitches.

[Mohan Kumar]

Thanks Glenn, 

Given below is the information related to your questions from dumpsys.

Android version : 4.4.2

Sample rate : 48000 Hz

bps : 16 bits

frame format:  stereo

frames/buffer : 128

Clients:

  pid: 784

  pid: 1052

Notification Clients:

  pid: 142

  pid: 784

  pid: 1052

Global session refs:

 session pid count

       5 1052   1

      12 784   1

      15 784   1

      16 784   1

Hardware status: 0

Standby Time mSec: 3000

Output thread 0xb711e050 internals

Normal frame count: 1024

last write occurred (msecs): 11

total writes: 801

delayed writes: 0

blocked in write: 0

suspend count: 0

mix buffer : 0xb7109ef0

Fast track availMask=0xf8

io handle: 2

TID: 812

standby: 0

Sample rate: 48000

HAL frame count: 128

Channel Count: 2

Channel Mask: 0x00000003

Format: 1

Frame size: 4

Pending setParameters commands:

 Index Command

Pending config events:

AudioMixer tracks: 0000000f

FastMixer command=MIX_WRITE writeSequence=12876 framesWritten=824064

          numTracks=1 writeErrors=0 underruns=1629 overruns=1567

          sampleRate=48000 frameCount=128 measuredWarmup=147 ms, warmupCycles=8

          mixPeriod=2.67 ms

Simple moving statistics over last 0.7 seconds:

  wall clock time in ms per mix cycle:

    mean=2.94 min=0.36 max=131.38 stddev=8.17

  raw CPU load in us per mix cycle:

    mean=1059 min=0 max=2790 stddev=344

Fast tracks: kMaxFastTracks=8 activeMask=0x1

Index Active Full Partial Empty  Recent Ready

    0    yes  252       0     2    full  1664

    1     no    0       0     0    full     0

    2     no   17       0    63   empty     0

    3     no    0       0     0    full     0

    4     no    0       0     0    full     0

    5     no    0       0     0    full     0

    6     no    0       0     0    full     0

    7     no    0       0     0    full     0

Output thread 0xb711e050 stream volumes in dB:

    0:-4.7, 1:-17, 2:-11, 3:-7.4, 4:-11, 5:-11, 6:0, 7:-17, 8:-11, 9:-7.4

Output thread 0xb711e050 tracks

   Name Client Type      Fmt Chn mask Session fCount S F SRate  L dB  R dB    Server Main buf  Aux Buf Flags UndFrmCnt

   F  1   1052    0 00000001 00000001       5    128 I 0 48000   -10   -10  00000000 B7109EF0 00000000 0x000         0

      2    784    1 00000001 00000001      12   1395 S 1 44100  -Inf  -Inf  00000573 B7109EF0 00000000 0x600         0

   F  2    784    2 00000001 00000001      16    128 S 1 48000     0     0  00000880 B7109EF0 00000000 0x600      1408

      1    784    1 00000001 00000001      15   1395 S 1 44100  -Inf  -Inf  00000573 B7109EF0 00000000 0x600         0

Output thread 0xb711e050 active tracks

   Name Client Type      Fmt Chn mask Session fCount S F SRate  L dB  R dB    Server Main buf  Aux Buf Flags UndFrmCnt

Normal mixer raw underrun counters: partial=0 empty=2

- 0 Effect Chains:

The difference I could see when tone is heard properly and when it's not is the "UndFrmCnt". When the tone is proper UndFrmCnt is not incrementing.