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avfilter/af_astats: add entropy stat
This commit is contained in:
Paul B Mahol
parent
463c71b3b3
commit
966fc3c070
@ -2693,6 +2693,7 @@ Flat_factor
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Peak_count
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Noise_floor
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Noise_floor_count
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Entropy
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Bit_depth
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Dynamic_range
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Zero_crossings
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@ -2717,6 +2718,7 @@ Flat_factor
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Peak_count
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Noise_floor
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Noise_floor_count
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Entropy
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Bit_depth
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Number_of_samples
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Number_of_NaNs
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@ -2795,6 +2797,9 @@ Minimum local peak measured in dBFS over a short window.
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Number of occasions (not the number of samples) that the signal attained
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@var{Noise floor}.
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@item Entropy
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Entropy measured across whole audio. Entropy of value near 1.0 is typically measured for white noise.
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@item Bit depth
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Overall bit depth of audio. Number of bits used for each sample.
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@ -57,6 +57,7 @@
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#define MEASURE_NUMBER_OF_DENORMALS (1 << 21)
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#define MEASURE_NOISE_FLOOR (1 << 22)
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#define MEASURE_NOISE_FLOOR_COUNT (1 << 23)
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#define MEASURE_ENTROPY (1 << 24)
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#define MEASURE_MINMAXPEAK (MEASURE_MIN_LEVEL | MEASURE_MAX_LEVEL | MEASURE_PEAK_LEVEL)
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@ -83,9 +84,11 @@ typedef struct ChannelStats {
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uint64_t nb_denormals;
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double *win_samples;
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uint64_t histogram[HISTOGRAM_SIZE];
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uint64_t ehistogram[HISTOGRAM_SIZE];
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int win_pos;
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int max_index;
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double noise_floor;
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double entropy;
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} ChannelStats;
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typedef struct AudioStatsContext {
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@ -135,6 +138,7 @@ static const AVOption astats_options[] = {
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{ "Zero_crossings_rate" , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_ZERO_CROSSINGS_RATE }, 0, 0, FLAGS, "measure" },
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{ "Noise_floor" , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NOISE_FLOOR }, 0, 0, FLAGS, "measure" },
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{ "Noise_floor_count" , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NOISE_FLOOR_COUNT }, 0, 0, FLAGS, "measure" },
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{ "Entropy" , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_ENTROPY }, 0, 0, FLAGS, "measure" },
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{ "Number_of_samples" , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NUMBER_OF_SAMPLES }, 0, 0, FLAGS, "measure" },
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{ "Number_of_NaNs" , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NUMBER_OF_NANS }, 0, 0, FLAGS, "measure" },
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{ "Number_of_Infs" , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NUMBER_OF_INFS }, 0, 0, FLAGS, "measure" },
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@ -199,9 +203,11 @@ static void reset_stats(AudioStatsContext *s)
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p->last = NAN;
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p->noise_floor = NAN;
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p->noise_floor_count = 0;
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p->entropy = 0;
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p->win_pos = 0;
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memset(p->win_samples, 0, s->tc_samples * sizeof(*p->win_samples));
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memset(p->histogram, 0, sizeof(p->histogram));
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memset(p->ehistogram, 0, sizeof(p->ehistogram));
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}
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}
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@ -254,6 +260,20 @@ static void bit_depth(AudioStatsContext *s, uint64_t mask, uint64_t imask, AVRat
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depth->num++;
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}
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static double calc_entropy(AudioStatsContext *s, ChannelStats *p)
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{
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double entropy = 0.;
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for (int i = 0; i < HISTOGRAM_SIZE; i++) {
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double entry = p->ehistogram[i] / ((double)p->nb_samples);
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if (entry > 1e-8)
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entropy += entry * log2(entry);
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}
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return -entropy / log2(HISTOGRAM_SIZE);
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}
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static inline void update_minmax(AudioStatsContext *s, ChannelStats *p, double d)
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{
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if (d < p->min)
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@ -319,6 +339,7 @@ static inline void update_stat(AudioStatsContext *s, ChannelStats *p, double d,
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index = av_clip(lrint(av_clipd(FFABS(nd), 0.0, 1.0) * HISTOGRAM_MAX), 0, HISTOGRAM_MAX);
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p->max_index = FFMAX(p->max_index, index);
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p->histogram[index]++;
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p->ehistogram[index]++;
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if (!isnan(p->noise_floor))
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p->histogram[av_clip(lrint(av_clipd(FFABS(drop), 0.0, 1.0) * HISTOGRAM_MAX), 0, HISTOGRAM_MAX)]--;
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p->win_pos++;
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@ -406,6 +427,7 @@ static void set_metadata(AudioStatsContext *s, AVDictionary **metadata)
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sigma_x = 0,
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sigma_x2 = 0,
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noise_floor = 0,
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entropy = 0,
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min_sigma_x2 = DBL_MAX,
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max_sigma_x2 =-DBL_MAX;
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AVRational depth;
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@ -431,6 +453,8 @@ static void set_metadata(AudioStatsContext *s, AVDictionary **metadata)
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sigma_x2 += p->sigma_x2;
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noise_floor = FFMAX(noise_floor, p->noise_floor);
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noise_floor_count += p->noise_floor_count;
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p->entropy = calc_entropy(s, p);
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entropy += p->entropy;
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min_count += p->min_count;
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max_count += p->max_count;
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min_runs += p->min_runs;
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@ -476,6 +500,8 @@ static void set_metadata(AudioStatsContext *s, AVDictionary **metadata)
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set_meta(metadata, c + 1, "Noise_floor", "%f", LINEAR_TO_DB(p->noise_floor));
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if (s->measure_perchannel & MEASURE_NOISE_FLOOR_COUNT)
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set_meta(metadata, c + 1, "Noise_floor_count", "%f", p->noise_floor_count);
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if (s->measure_perchannel & MEASURE_ENTROPY)
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set_meta(metadata, c + 1, "Entropy", "%f", p->entropy);
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if (s->measure_perchannel & MEASURE_BIT_DEPTH) {
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bit_depth(s, p->mask, p->imask, &depth);
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set_meta(metadata, c + 1, "Bit_depth", "%f", depth.num);
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@ -525,6 +551,8 @@ static void set_metadata(AudioStatsContext *s, AVDictionary **metadata)
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set_meta(metadata, 0, "Overall.Noise_floor", "%f", LINEAR_TO_DB(noise_floor));
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if (s->measure_overall & MEASURE_NOISE_FLOOR_COUNT)
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set_meta(metadata, 0, "Overall.Noise_floor_count", "%f", noise_floor_count / (double)s->nb_channels);
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if (s->measure_overall & MEASURE_ENTROPY)
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set_meta(metadata, 0, "Overall.Entropy", "%f", entropy / (double)s->nb_channels);
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if (s->measure_overall & MEASURE_BIT_DEPTH) {
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bit_depth(s, mask, imask, &depth);
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set_meta(metadata, 0, "Overall.Bit_depth", "%f", depth.num);
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@ -655,6 +683,7 @@ static void print_stats(AVFilterContext *ctx)
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sigma_x = 0,
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sigma_x2 = 0,
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noise_floor = 0,
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entropy = 0,
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min_sigma_x2 = DBL_MAX,
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max_sigma_x2 =-DBL_MAX;
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AVRational depth;
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@ -679,6 +708,8 @@ static void print_stats(AVFilterContext *ctx)
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sigma_x += p->sigma_x;
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sigma_x2 += p->sigma_x2;
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noise_floor = FFMAX(noise_floor, p->noise_floor);
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p->entropy = calc_entropy(s, p);
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entropy += p->entropy;
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min_count += p->min_count;
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max_count += p->max_count;
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noise_floor_count += p->noise_floor_count;
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@ -728,6 +759,8 @@ static void print_stats(AVFilterContext *ctx)
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av_log(ctx, AV_LOG_INFO, "Noise floor dB: %f\n", LINEAR_TO_DB(p->noise_floor));
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if (s->measure_perchannel & MEASURE_NOISE_FLOOR_COUNT)
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av_log(ctx, AV_LOG_INFO, "Noise floor count: %"PRId64"\n", p->noise_floor_count);
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if (s->measure_perchannel & MEASURE_ENTROPY)
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av_log(ctx, AV_LOG_INFO, "Entropy: %f\n", p->entropy);
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if (s->measure_perchannel & MEASURE_BIT_DEPTH) {
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bit_depth(s, p->mask, p->imask, &depth);
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av_log(ctx, AV_LOG_INFO, "Bit depth: %u/%u\n", depth.num, depth.den);
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@ -779,6 +812,8 @@ static void print_stats(AVFilterContext *ctx)
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av_log(ctx, AV_LOG_INFO, "Noise floor dB: %f\n", LINEAR_TO_DB(noise_floor));
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if (s->measure_overall & MEASURE_NOISE_FLOOR_COUNT)
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av_log(ctx, AV_LOG_INFO, "Noise floor count: %f\n", noise_floor_count / (double)s->nb_channels);
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if (s->measure_overall & MEASURE_ENTROPY)
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av_log(ctx, AV_LOG_INFO, "Entropy: %f\n", entropy / (double)s->nb_channels);
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if (s->measure_overall & MEASURE_BIT_DEPTH) {
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bit_depth(s, mask, imask, &depth);
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av_log(ctx, AV_LOG_INFO, "Bit depth: %u/%u\n", depth.num, depth.den);
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