Hi all,
I found some audio noise problem when I trying to set the sink
latency to a lower value.
here is the alsa dump:
D/NMAudio ( 1959): Its setup is:
D/NMAudio ( 1959): stream : PLAYBACK
D/NMAudio ( 1959): access : MMAP_INTERLEAVED
D/NMAudio ( 1959): format : S16_LE
D/NMAudio ( 1959): subformat : STD
D/NMAudio ( 1959): channels : 2
D/NMAudio ( 1959): rate : 22050
D/NMAudio ( 1959): exact rate : 22050 (22050/1)
D/NMAudio ( 1959): msbits : 16
D/NMAudio ( 1959): buffer_size : 8192
D/NMAudio ( 1959): period_size : 2048
D/NMAudio ( 1959): period_time : 92879
D/NMAudio ( 1959): tstamp_mode : ENABLE
D/NMAudio ( 1959): period_step : 1
D/NMAudio ( 1959): avail_min : 7751
D/NMAudio ( 1959): period_event : 0
D/NMAudio ( 1959): start_threshold : -1
D/NMAudio ( 1959): stop_threshold : 1073741824
D/NMAudio ( 1959): silence_threshold: 0
D/NMAudio ( 1959): s
here is the log when problem happened:
E/NMAudio ( 1959): [1991] ( 355.00387| 0.000) pcm_avail = 30124 , 7531
D/NMAudio ( 1959): [1991] ( 355.00387| 0.000) avail: 30124,
left_to_play: 29.98ms, process_usec=20.00ms, max_sleep_usec=10.00ms
D/NMAudio ( 1959): [1991] ( 355.00387| 0.000) Not filling up,
because too early.
D/NMAudio ( 1959): [1991][audioio] snd_pcm_avail[0][0xb344efa0]=7531
E/NMAudio ( 1959): [1991] ( 355.00387| 0.000) pcm_avail = 30124 , 7531
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) avail: 30124,
left_to_play: 29.98ms, process_usec=20.00ms, max_sleep_usec=10.00ms
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) Not filling up,
because too early.
D/NMAudio ( 1959): [1991][audioio] snd_pcm_avail[0][0xb344efa0]=7531
E/NMAudio ( 1959): [1991] ( 355.00388| 0.000) pcm_avail = 30124 , 7531
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) avail: 30124,
left_to_play: 29.98ms, process_usec=20.00ms, max_sleep_usec=10.00ms
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) Not filling up,
because too early.
D/NMAudio ( 1959): [1991][audioio] snd_pcm_avail[0][0xb344efa0]=7531
E/NMAudio ( 1959): [1991] ( 355.00388| 0.000) pcm_avail = 30124 , 7531
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) avail: 30124,
left_to_play: 29.98ms, process_usec=20.00ms, max_sleep_usec=10.00ms
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) Not filling up,
because too early.
D/NMAudio ( 1959): [1991][audioio] snd_pcm_avail[0][0xb344efa0]=7531
E/NMAudio ( 1959): [1991] ( 355.00388| 0.000) pcm_avail = 30124 , 7531
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) avail: 30124,
left_to_play: 29.98ms, process_usec=20.00ms, max_sleep_usec=10.00ms
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) Not filling up,
because too early.
D/NMAudio ( 1959): [1991][audioio] snd_pcm_avail[0][0xb344efa0]=7531
E/NMAudio ( 1959): [1991] ( 355.00388| 0.000) pcm_avail = 30124 , 7531
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) avail: 30124,
left_to_play: 29.98ms, process_usec=20.00ms, max_sleep_usec=10.00ms
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) Not filling up,
because too early.
D/NMAudio ( 1959): [1991][audioio] snd_pcm_avail[0][0xb344efa0]=7531
E/NMAudio ( 1959): [1991] ( 355.00388| 0.000) pcm_avail = 30124 , 7531
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) avail: 30124,
left_to_play: 29.98ms, process_usec=20.00ms, max_sleep_usec=10.00ms
D/NMAudio ( 1959): [1991] ( 355.00388| 0.000) Not filling up,
because too early.
D/NMAudio ( 1959): [1991][audioio] snd_pcm_avail[0][0xb344efa0]=7531
E/NMAudio ( 1959): [1991] ( 355.00399| 0.010) pcm_avail = 30124 , 7531
D/NMAudio ( 1959): [1991] ( 355.00399| 0.000) avail: 30124,
left_to_play: 29.98ms, process_usec=20.00ms, max_sleep_usec=10.00ms
D/NMAudio ( 1959): [1991] ( 355.00399| 0.000) Not filling up,
because too early.
D/NMAudio ( 1959): [1991][audioio] snd_pcm_avail[0][0xb344efa0]=7531
E/NMAudio ( 1959): [1991] ( 355.00405| 0.005) pcm_avail = 30124 , 7531
D/NMAudio ( 1959): [1991] ( 355.00405| 0.000) avail: 30124,
left_to_play: 29.98ms, process_usec=20.00ms, max_sleep_usec=10.00ms
D/NMAudio ( 1959): [1991] ( 355.00405| 0.000) Not filling up,
because too early.
D/NMAudio ( 1959): [1991][audioio] snd_pcm_avail[0][0xb344efa0]=7531
E/NMAudio ( 1959): [1991] ( 355.00405| 0.000) pcm_avail = 30124 , 7531
D/NMAudio ( 1959): [1991] ( 355.00405| 0.000) avail: 30124,
left_to_play: 29.98ms, process_usec=20.00ms, max_sleep_usec=10.00ms
D/NMAudio ( 1959): [1991] ( 355.00405| 0.000) Not filling up,
because too early.
D/NMAudio ( 1959): [1991] ( 355.00405| 0.000) Wakeup from ALSA!
D/NMAudio ( 1959): [1991][audioio] snd_pcm_avail[0][0xb344efa0]=9579
E/NMAudio ( 1959): [1991] ( 355.00406| 0.000) pcm_avail = 38316 , 9579
D/NMAudio ( 1959): [1991] ( 355.00406| 0.000)
Underrun(sink-state=0)! (alsa-left=38316, whole-buffer=32768)
I/NMAudio ( 1959): [1991] ( 355.00406| 0.000) Increasing minimal
latency to 2.00 ms
I/NMAudio ( 1959): [1991] ( 355.00406| 0.000) sink audioio.0
latency range(2000, 371519)
D/NMAudio ( 1959): [1991] ( 355.00406| 0.000) update_sw_params
get_request_latency = 30000
seems like snd_pcm_avail result is not so reliable
first of all, the hw buffer size is set to 8192 frames, but in the
red line, it became 9579.
second, check the blue lines from time 355.00387 to 355.00405
the snd_pcm_avail is always 7531 frames, this is 19 ms long, but
snd_pcm_avail value is never changed, is it
a problem ?
Does anyone met this problem before? I would appreciate hearing
your advice on this.
Thanks!
BR,
Lixin
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