Re: [igt-dev] [PATCH i-g-t 2/2] lib/igt_audio: sanity-check generated signals

[Martin Peres <martin.peres@intel.com>]

On 17/05/2019 13:11, Simon Ser wrote:
> This is a safety net to ensure we haven't completely messed up our signal
> generation. It would be unfortunate to send e.g. a null signal after a
> refactoring.
> 
> Signed-off-by: Simon Ser <simon.ser@intel.com>
> ---
>  lib/igt_audio.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/lib/igt_audio.c b/lib/igt_audio.c
> index f6c8e399e345..0d7422c6f3ec 100644
> --- a/lib/igt_audio.c
> +++ b/lib/igt_audio.c
> @@ -213,6 +213,34 @@ static size_t audio_signal_count_freqs(struct audio_signal *signal, int channel)
>  	return n;
>  }
>  
> +/** audio_sanity_check:
> + *
> + * Make sure our generated signal is not messed up. In particular, make sure
> + * the maximum reaches a reasonable value but doesn't exceed our
> + * SYNTHESIZE_AMPLITUDE limit. Same for the minimum.
> + *
> + * We want the signal to be powerful enough to be able to hear something. We
> + * want the signal not to reach 1.0 so that we're sure it won't get capped by
> + * the audio card or the receiver.
> + */
> +static void audio_sanity_check(double *samples, size_t samples_len)
> +{
> +	size_t i;
> +	double min = 0, max = 0;
> +
> +	for (i = 0; i < samples_len; i++) {
> +		if (samples[i] < min)
> +			min = samples[i];
> +		if (samples[i] > max)
> +			max = samples[i];
> +	}
> +
> +	igt_assert(-SYNTHESIZE_AMPLITUDE <= min);
> +	igt_assert(min <= -SYNTHESIZE_AMPLITUDE + 0.2);
> +	igt_assert(SYNTHESIZE_AMPLITUDE - 0.2 <= max);
> +	igt_assert(max <= SYNTHESIZE_AMPLITUDE);

Maybe we should make the 0.2 a MACRO? Anyway, looks good!

Reviewed-by: Martin Peres <martin.peres@linux.intel.com>
> +}
> +
>  /**
>   * audio_signal_fill:
>   * @signal: The target signal structure
> @@ -268,6 +296,8 @@ void audio_signal_fill(struct audio_signal *signal, double *buffer,
>  			total += count;
>  		}
>  	}
> +
> +	audio_sanity_check(buffer, signal->channels * samples);
>  }
>  
>  void audio_signal_fill_s16_le(struct audio_signal *signal, int16_t *buffer,
> 
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