[FFmpeg-devel] [PATCH] avfilter/af_astats: calculate audio bit-depth

[Paul B Mahol]

On 7/15/15, wm4 <nfxjfg at googlemail.com> wrote:
> On Tue, 14 Jul 2015 22:01:48 +0000
> Paul B Mahol <onemda at gmail.com> wrote:
>
>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>> ---
>>  libavfilter/af_astats.c | 21 +++++++++++++++++++--
>>  1 file changed, 19 insertions(+), 2 deletions(-)
>>
>> diff --git a/libavfilter/af_astats.c b/libavfilter/af_astats.c
>> index a89ac6d..21cec8c 100644
>> --- a/libavfilter/af_astats.c
>> +++ b/libavfilter/af_astats.c
>> @@ -33,6 +33,7 @@ typedef struct ChannelStats {
>>      double min, max;
>>      double min_run, max_run;
>>      double min_runs, max_runs;
>> +    uint64_t mask;
>>      uint64_t min_count, max_count;
>>      uint64_t nb_samples;
>>  } ChannelStats;
>> @@ -121,6 +122,15 @@ static int config_output(AVFilterLink *outlink)
>>      return 0;
>>  }
>>
>> +static unsigned bit_depth(uint64_t mask)
>> +{
>> +    unsigned result = 64;
>> +
>> +    for (; result && !(mask & 1); --result, mask >>= 1);
>> +
>> +    return result;
>> +}
>> +
>>  static inline void update_stat(AudioStatsContext *s, ChannelStats *p,
>> double d)
>>  {
>>      if (d < p->min) {
>> @@ -151,6 +161,7 @@ static inline void update_stat(AudioStatsContext *s,
>> ChannelStats *p, double d)
>>      p->sigma_x2 += d * d;
>>      p->avg_sigma_x2 = p->avg_sigma_x2 * s->mult + (1.0 - s->mult) * d *
>> d;
>>      p->last = d;
>> +    p->mask |= llrint(d * (1LLU<<63));
>>
>>      if (p->nb_samples >= s->tc_samples) {
>>          p->max_sigma_x2 = FFMAX(p->max_sigma_x2, p->avg_sigma_x2);
>> @@ -177,7 +188,7 @@ static void set_meta(AVDictionary **metadata, int
>> chan, const char *key,
>>
>>  static void set_metadata(AudioStatsContext *s, AVDictionary **metadata)
>>  {
>> -    uint64_t min_count = 0, max_count = 0, nb_samples = 0;
>> +    uint64_t mask = 0, min_count = 0, max_count = 0, nb_samples = 0;
>>      double min_runs = 0, max_runs = 0,
>>             min = DBL_MAX, max = DBL_MIN,
>>             max_sigma_x = 0,
>> @@ -203,6 +214,7 @@ static void set_metadata(AudioStatsContext *s,
>> AVDictionary **metadata)
>>          max_count += p->max_count;
>>          min_runs += p->min_runs;
>>          max_runs += p->max_runs;
>> +        mask |= p->mask;
>>          nb_samples += p->nb_samples;
>>          if (fabs(p->sigma_x) > fabs(max_sigma_x))
>>              max_sigma_x = p->sigma_x;
>> @@ -217,6 +229,7 @@ static void set_metadata(AudioStatsContext *s,
>> AVDictionary **metadata)
>>          set_meta(metadata, c + 1, "Crest_factor", "%f", p->sigma_x2 ?
>> FFMAX(-p->min, p->max) / sqrt(p->sigma_x2 / p->nb_samples) : 1);
>>          set_meta(metadata, c + 1, "Flat_factor", "%f",
>> LINEAR_TO_DB((p->min_runs + p->max_runs) / (p->min_count +
>> p->max_count)));
>>          set_meta(metadata, c + 1, "Peak_count", "%f",
>> (float)(p->min_count + p->max_count));
>> +        set_meta(metadata, c + 1, "Bit-depth", "%f", bit_depth(p->mask));
>>      }
>>
>>      set_meta(metadata, 0, "Overall.DC_offset", "%f", max_sigma_x /
>> (nb_samples / s->nb_channels));
>> @@ -228,6 +241,7 @@ static void set_metadata(AudioStatsContext *s,
>> AVDictionary **metadata)
>>      set_meta(metadata, 0, "Overall.RMS_trough", "%f",
>> LINEAR_TO_DB(sqrt(min_sigma_x2)));
>>      set_meta(metadata, 0, "Overall.Flat_factor", "%f",
>> LINEAR_TO_DB((min_runs + max_runs) / (min_count + max_count)));
>>      set_meta(metadata, 0, "Overall.Peak_count", "%f", (float)(min_count +
>> max_count) / (double)s->nb_channels);
>> +    set_meta(metadata, 0, "Overall.Bit-depth", "%f", bit_depth(mask));
>>      set_meta(metadata, 0, "Overall.Number_of_samples", "%f", nb_samples /
>> s->nb_channels);
>
> So why would everything use _ as separate, except bit depth?

Everything other use '_' instead of ' '. I do not think '-' should be
replaced by '_'.

>
>>  }
>>
>> @@ -276,7 +290,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame
>> *buf)
>>  static void print_stats(AVFilterContext *ctx)
>>  {
>>      AudioStatsContext *s = ctx->priv;
>> -    uint64_t min_count = 0, max_count = 0, nb_samples = 0;
>> +    uint64_t mask = 0, min_count = 0, max_count = 0, nb_samples = 0;
>>      double min_runs = 0, max_runs = 0,
>>             min = DBL_MAX, max = DBL_MIN,
>>             max_sigma_x = 0,
>> @@ -302,6 +316,7 @@ static void print_stats(AVFilterContext *ctx)
>>          max_count += p->max_count;
>>          min_runs += p->min_runs;
>>          max_runs += p->max_runs;
>> +        mask |= p->mask;
>>          nb_samples += p->nb_samples;
>>          if (fabs(p->sigma_x) > fabs(max_sigma_x))
>>              max_sigma_x = p->sigma_x;
>> @@ -318,6 +333,7 @@ static void print_stats(AVFilterContext *ctx)
>>          av_log(ctx, AV_LOG_INFO, "Crest factor: %f\n", p->sigma_x2 ?
>> FFMAX(-p->min, p->max) / sqrt(p->sigma_x2 / p->nb_samples) : 1);
>>          av_log(ctx, AV_LOG_INFO, "Flat factor: %f\n",
>> LINEAR_TO_DB((p->min_runs + p->max_runs) / (p->min_count +
>> p->max_count)));
>>          av_log(ctx, AV_LOG_INFO, "Peak count: %"PRId64"\n", p->min_count
>> + p->max_count);
>> +        av_log(ctx, AV_LOG_INFO, "Bit-depth: %u\n", bit_depth(p->mask));
>>      }
>>
>>      av_log(ctx, AV_LOG_INFO, "Overall\n");
>> @@ -331,6 +347,7 @@ static void print_stats(AVFilterContext *ctx)
>>          av_log(ctx, AV_LOG_INFO, "RMS trough dB: %f\n",
>> LINEAR_TO_DB(sqrt(min_sigma_x2)));
>>      av_log(ctx, AV_LOG_INFO, "Flat factor: %f\n", LINEAR_TO_DB((min_runs
>> + max_runs) / (min_count + max_count)));
>>      av_log(ctx, AV_LOG_INFO, "Peak count: %f\n", (min_count + max_count)
>> / (double)s->nb_channels);
>> +    av_log(ctx, AV_LOG_INFO, "Bit-depth: %u\n", bit_depth(mask));
>>      av_log(ctx, AV_LOG_INFO, "Number of samples: %"PRId64"\n", nb_samples
>> / s->nb_channels);
>>  }
>>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>