[FFmpeg-devel] [PATCHv2] af_hdcd: Add analyze mode

[Michael Niedermayer]

On Fri, Aug 05, 2016 at 05:23:04PM -0500, Burt P wrote:
> A new mode, selected by filter option, to aid in analysis of HDCD
> encoded audio. In this mode the audio is replaced by a solid tone and
> the amplitude is adjusted to signal some specified aspect of the process.
> The output file can be loaded in an audio editor alongside the original,
> where the user can see where different features or states are present.



[...]

> @@ -1358,18 +1478,32 @@ static void hdcd_process_stereo(HDCDContext *ctx, int32_t *samples, int count)
>          count -= envelope_run;
>          lead = run - envelope_run;
>  
> -        hdcd_control_stereo(ctx, &peak_extend[0], &peak_extend[1]);
> +        ctlret = hdcd_control_stereo(ctx, &peak_extend[0], &peak_extend[1]);
>      }
>      if (lead > 0) {
>          av_assert0(samples + lead * stride <= samples_end);
> -        gain[0] = hdcd_envelope(samples, lead, stride, gain[0], ctx->val_target_gain, peak_extend[0]);
> -        gain[1] = hdcd_envelope(samples + 1, lead, stride, gain[1], ctx->val_target_gain, peak_extend[1]);
> +        if (ctx->analyze_mode) {
> +            gain[0] = hdcd_analyze(samples, lead, stride, gain[0], ctx->val_target_gain, peak_extend[0],
> +                ctx->analyze_mode,
> +                ctx->state[0].sustain,
> +                !!(ctlret == HDCD_TG_MISMATCH) );
> +            gain[1] = hdcd_analyze(samples + 1, lead, stride, gain[1], ctx->val_target_gain, peak_extend[1],
> +                ctx->analyze_mode,
> +                ctx->state[1].sustain,
> +                !!(ctlret == HDCD_TG_MISMATCH) );
> +        } else {
> +            gain[0] = hdcd_envelope(samples, lead, stride, gain[0], ctx->val_target_gain, peak_extend[0]);
> +            gain[1] = hdcd_envelope(samples + 1, lead, stride, gain[1], ctx->val_target_gain, peak_extend[1]);
> +        }
>      }
>  
>      ctx->state[0].running_gain = gain[0];
>      ctx->state[1].running_gain = gain[1];
>  }
>  

> +/* tone generator: sample_number, frequency, sample_rate, amplitude */
> +#define TONEGEN16(sn, f, sr, a) (int16_t)(sin((6.28318530718 * sn * f) /sr) * a * 0x7fff)

missing () for argument protection
TONEGEN16(1+1,2+3,4+5,6+7) wont do what one expects otherwise


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The educated differ from the uneducated as much as the living from the
dead. -- Aristotle 
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