[vlc-devel] [PATCH 1/4] coreaudio: add ca_MuteSet()

[Rémi Denis-Courmont]

Le keskiviikkona 21. huhtikuuta 2021, 18.00.38 EEST Thomas Guillem a écrit :
> This will write 0s from the render callback without touching at the
> playback buffer state.
> ---
>  modules/audio_output/coreaudio_common.c | 16 +++++++++++++++-
>  modules/audio_output/coreaudio_common.h |  3 +++
>  2 files changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/modules/audio_output/coreaudio_common.c
> b/modules/audio_output/coreaudio_common.c index fd8ee7279d6..4c96a1ffbd6
> 100644
> --- a/modules/audio_output/coreaudio_common.c
> +++ b/modules/audio_output/coreaudio_common.c
> @@ -189,7 +189,10 @@ ca_Render(audio_output_t *p_aout, uint32_t i_frames,
> uint64_t i_host_time, while (p_block != NULL && i_requested != 0)
>      {
>          size_t i_tocopy = __MIN(i_requested, p_block->i_buffer);
> -        memcpy(p_output, p_block->p_buffer, i_tocopy);
> +        if (unlikely(p_sys->b_muted))
> +            memset(p_output, 0, i_tocopy);
> +        else
> +            memcpy(p_output, p_block->p_buffer, i_tocopy);
>          i_requested -= i_tocopy;
>          i_copied += i_tocopy;
>          p_output += i_tocopy;
> @@ -299,6 +302,16 @@ ca_Pause(audio_output_t * p_aout, bool pause,
> vlc_tick_t date) lock_unlock(p_sys);
>  }
> 
> +void
> +ca_MuteSet(audio_output_t * p_aout, bool muted)
> +{
> +    struct aout_sys_common *p_sys = (struct aout_sys_common *) p_aout->sys;
> +
> +    lock_lock(p_sys);
> +    p_sys->b_muted = muted;
> +    lock_unlock(p_sys);
> +}

You'd achieve the same pseudo-racy behaviour with an atomic boolean.

> +
>  void
>  ca_Play(audio_output_t * p_aout, block_t * p_block, vlc_tick_t date)
>  {
> @@ -400,6 +413,7 @@ ca_Initialize(audio_output_t *p_aout, const
> audio_sample_format_t *fmt,
> 
>      p_sys->i_underrun_size = 0;
>      p_sys->b_paused = false;
> +    p_sys->b_muted = false;
>      p_sys->i_render_host_time = p_sys->i_first_render_host_time = 0;
>      p_sys->i_render_frames = 0;
> 
> diff --git a/modules/audio_output/coreaudio_common.h
> b/modules/audio_output/coreaudio_common.h index 4bd61394937..faa3286e1d1
> 100644
> --- a/modules/audio_output/coreaudio_common.h
> +++ b/modules/audio_output/coreaudio_common.h
> @@ -53,6 +53,7 @@ struct aout_sys_common
> 
>      size_t              i_underrun_size;
>      bool                b_paused;
> +    bool                b_muted;
>      bool                b_do_flush;
> 
>      size_t              i_out_max_size;
> @@ -95,6 +96,8 @@ void ca_Flush(audio_output_t *p_aout);
> 
>  void ca_Pause(audio_output_t * p_aout, bool pause, vlc_tick_t date);
> 
> +void ca_MuteSet(audio_output_t * p_aout, bool mute);
> +
>  void ca_Play(audio_output_t * p_aout, block_t * p_block, vlc_tick_t date);
> 
>  int  ca_Initialize(audio_output_t *p_aout, const audio_sample_format_t
> *fmt,


-- 
Rémi Denis-Courmont
http://www.remlab.net/