[pulseaudio-discuss] Audible plop at beginning when using pcat-simple

[guest271314]

Why is the sample rate set to 48000?

On Fri, Aug 27, 2021 at 6:40 AM mindfsck <mindfsck at gmail.com> wrote:

> Thanks Sean. I unloaded the suspend module but the plop is still there.
> I don't really think it is HW related since the file plays just fine with
> paplay and aplay.
>
> On Fri, Aug 27, 2021 at 5:49 AM Sean Greenslade <sean at seangreenslade.com>
> wrote:
>
>> On Thu, Aug 26, 2021 at 09:43:23PM +0200, mindfsck wrote:
>> > Hi there,
>> >
>> > I was using this example to simply play a WAV file without having much
>> clue
>> > of audio:
>> >
>> https://www.freedesktop.org/software/pulseaudio/doxygen/pacat-simple_8c-example.html
>> > I changed the sources to match (IMHO) my settings, i.e. channels=1 and
>> > rate=48000.
>> >
>> > I have two wavefiles, the first plays as it should (compared with
>> command
>> > line paplay or aplay) and the second one has an audible PLOP (but only
>> > around 90% of the time) at the very beginning of playback:
>> >
>> > (1 - OK)
>> > General
>> > Complete name                            : out_clean.wav
>> > Format                                   : Wave
>> > File size                                : 81.3 KiB
>> > Duration                                 : 866 ms
>> > Overall bit rate mode                    : Constant
>> > Overall bit rate                         : 769 kb/s
>> > Audio
>> > Format                                   : PCM
>> > Format settings                          : Little / Signed
>> > Codec ID                                 : 1
>> > Duration                                 : 866 ms
>> > Bit rate mode                            : Constant
>> > Bit rate                                 : 768 kb/s
>> > Channel(s)                               : 1 channel
>> > Sampling rate                            : 48.0 kHz
>> > Bit depth                                : 16 bits
>> > Stream size                              : 81.2 KiB (100%)
>> >
>> > (2 - NOK)
>> > General
>> > Complete name                            : out_short_clean.wav
>> > Format                                   : Wave
>> > File size                                : 22.8 KiB
>> > Duration                                 : 242 ms
>> > Overall bit rate mode                    : Constant
>> > Overall bit rate                         : 772 kb/s
>> > Audio
>> > Format                                   : PCM
>> > Format settings                          : Little / Signed
>> > Codec ID                                 : 1
>> > Duration                                 : 242 ms
>> > Bit rate mode                            : Constant
>> > Bit rate                                 : 768 kb/s
>> > Channel(s)                               : 1 channel
>> > Sampling rate                            : 48.0 kHz
>> > Bit depth                                : 16 bits
>> > Stream size                              : 22.8 KiB (100%)
>> >
>> > I tried using different BUFSIZE and my systemload is also not an
>> issue...
>> > Any ideas?
>>
>> I've experienced something like this with a few built-in audio cards on
>> various laptops. It's never bothered me enough to track it down, but I
>> suspect it's due to the suspending and resuming of cards. Can you try
>> disabling the autosuspend module and see if it still happens? Use this
>> command to temporarily disable it until the next time pulse reloads:
>>
>> $ pactl unload-module module-suspend-on-idle
>>
>> --Sean
>>
>>
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