Re: [PATCH v2 06/15] jackaudio: use more jack audio buffers

[Christian Schoenebeck]

On Samstag, 22. Januar 2022 13:57:36 CET Volker Rümelin wrote:
> The next patch reduces the effective qemu playback buffer size
> by timer-period. Increase the number of jack audio buffers by
> one to preserve the total effective buffer size. The size of one
> jack audio buffer is 512 samples. With audio defaults that's
> 512 samples / 44100 samples/s = 11.6 ms and only slightly larger
> than the timer-period of 10 ms.
> 
> The larger jack audio buffer increases audio dropout safety,
> because the high priority jack-audio worker threads can provide
> audio data for a longer period of time as with a smaller buffer
> and more audio data in the mixing engine buffer that they can't
> access.
> 
> Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>

Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>

> ---
>  audio/jackaudio.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/audio/jackaudio.c b/audio/jackaudio.c
> index 317009e936..26246c3a8b 100644
> --- a/audio/jackaudio.c
> +++ b/audio/jackaudio.c
> @@ -483,8 +483,8 @@ static int qjack_client_init(QJackClient *c)
>          c->buffersize = 512;
>      }
> 
> -    /* create a 2 period buffer */
> -    qjack_buffer_create(&c->fifo, c->nchannels, c->buffersize * 2);
> +    /* create a 3 period buffer */
> +    qjack_buffer_create(&c->fifo, c->nchannels, c->buffersize * 3);
> 
>      qjack_client_connect_ports(c);
>      c->state = QJACK_STATE_RUNNING;