* [FFmpeg-devel] [PATCH] libavfilter/ebur128: SIMD optimization
@ 2025-04-17 14:33 gkhayat
2025-04-17 17:07 ` Andreas Rheinhardt
0 siblings, 1 reply; 4+ messages in thread
From: gkhayat @ 2025-04-17 14:33 UTC (permalink / raw)
To: ffmpeg-devel; +Cc: Guillaume Khayat, Cesar Matheus
From: Guillaume Khayat <gkhayat@spectre-music.com>
Improve performance (+17%) of ebur_128 filter using AVX2 and FMA instruction in the body of the filter_frame function.
## Benchmark
Tested with hyperfine
hyperfine --warmup 2 "./ffmpeg_reference -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -" "./ffmpeg_avx -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -"
Benchmark 1: ./ffmpeg_reference -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -
Time (mean ± σ): 7.118 s ± 0.037 s [User: 9.114 s, System: 1.038 s]
Range (min … max): 7.073 s … 7.177 s 10 runs
Benchmark 2: ./ffmpeg_avx -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -
Time (mean ± σ): 6.073 s ± 0.108 s [User: 7.903 s, System: 1.058 s]
Range (min … max): 5.955 s … 6.327 s 10 runs
Summary
./ffmpeg_avx -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null - ran
1.17 ± 0.02 times faster than ./ffmpeg_reference -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -
## Tests
- all FATE tests pass, tested on Darwin/arm64 and Linux/x86_64 w/ AVX2/FMA support
- On AVX2/FMA-capable system, all test files from the EBU yield the exact same output values (I/LRA) after and before optimization. See https://tech.ebu.ch/publications/ebu_loudness_test_set
Disclaimer: this is my first ever patch submission to FFmpeg, and first ever time using git send-email to submit a patch anywhere.
Signed-off-by: Cesar Matheus <cesar.matheus@telecom-paris.fr>
Signed-off-by: Guillaume Khayat <gkhayat@spectre-music.com>
---
libavfilter/f_ebur128.c | 246 ++++++++++++++++++++++++++++++++++------
1 file changed, 214 insertions(+), 32 deletions(-)
diff --git a/libavfilter/f_ebur128.c b/libavfilter/f_ebur128.c
index 768f062bac..e305b0a3ce 100644
--- a/libavfilter/f_ebur128.c
+++ b/libavfilter/f_ebur128.c
@@ -28,7 +28,7 @@
#include <float.h>
#include <math.h>
-
+#include "libavutil/intmath.h"
#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/dict.h"
@@ -199,7 +199,7 @@ static const AVOption ebur128_options[] = {
};
AVFILTER_DEFINE_CLASS(ebur128);
-
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
static const uint8_t graph_colors[] = {
0xdd, 0x66, 0x66, // value above 1LU non reached below -1LU (impossible)
0x66, 0x66, 0xdd, // value below 1LU non reached below -1LU
@@ -628,13 +628,61 @@ static int gate_update(struct integrator *integ, double power,
static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
{
- int i, ch, idx_insample, ret;
+
+ int i, ch, idx_insample, ret,bin_id_400,bin_id_3000;
AVFilterContext *ctx = inlink->dst;
EBUR128Context *ebur128 = ctx->priv;
const int nb_channels = ebur128->nb_channels;
const int nb_samples = insamples->nb_samples;
const double *samples = (double *)insamples->data[0];
AVFrame *pic;
+
+#if HAVE_AVX2_EXTERNAL && HAVE_AVX2
+ double bin[4];
+ __m256d pre_b_0,pre_b_1,pre_b_2,pre_a_1,pre_a_2,rlb_b_0,rlb_b_1,rlb_b_2,rlb_a_1,rlb_a_2,x1,x2,x0,y1,y2,y0,z1,z2,z0; //
+
+ /**
+ * Set each coeeficients value of pre_b,pre_a,rlb_b, rlb_a as vector variable of size 4, each element
+ * of the vectors corresponds to a channel, here we coded the case where there is 2 channel to deal with, case where nb_channel =3 or
+ * 4 can easily be implemented following the exact same methodology
+ */
+
+ // Case where nb_channel = 3 : pre_b_0 = _mm256_setr_ps(ebur128->pre_b[0],ebur128->pre_b[0], ebur128->pre_b[0], 0.0);
+ bin[0] = 0.0;
+ bin[1] = 0.0;
+ bin[2] = 0.0;
+ bin[3] = 0.0;
+
+ // Load pre_b coefficients in 3 4*64 bits vector
+ pre_b_0 = _mm256_set1_pd(ebur128->pre_b[0]);
+ pre_b_1 = _mm256_set1_pd(ebur128->pre_b[1]);
+ pre_b_2 = _mm256_set1_pd(ebur128->pre_b[2]);
+
+ // Load pre_a coefficients in 2 4*64 bits vector pre_a_0 is not used here so no need to lad it
+ pre_a_1 = _mm256_set1_pd(ebur128->pre_a[1]);
+ pre_a_2 = _mm256_set1_pd(ebur128->pre_a[2]);
+
+ // Load rlb_b
+ rlb_b_0 = _mm256_set1_pd(ebur128->rlb_b[0]);
+ rlb_b_1 = _mm256_set1_pd(ebur128->rlb_b[1]);
+ rlb_b_2 = _mm256_set1_pd(ebur128->rlb_b[2]);
+
+ // Load rlb_a
+ rlb_a_1 = _mm256_set1_pd(ebur128->rlb_a[1]);
+ rlb_a_2 = _mm256_set1_pd(ebur128->rlb_a[2]);
+
+ // At the start all the buffer filter are set at 0 in the start
+ x1 = _mm256_set1_pd(0.0);
+ x2 = _mm256_set1_pd(0.0);
+
+ y0 = _mm256_set1_pd(0.0);
+ y1 = _mm256_set1_pd(0.0);
+ y2 = _mm256_set1_pd(0.0);
+
+ z0 =_mm256_set1_pd(0.0);
+ z1 = _mm256_set1_pd(0.0);
+ z2 = _mm256_set1_pd(0.0);
+#endif
#if CONFIG_SWRESAMPLE
if (ebur128->peak_mode & PEAK_MODE_TRUE_PEAKS && ebur128->idx_insample == 0) {
@@ -657,8 +705,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
#endif
for (idx_insample = ebur128->idx_insample; idx_insample < nb_samples; idx_insample++) {
- const int bin_id_400 = ebur128->i400.cache_pos;
- const int bin_id_3000 = ebur128->i3000.cache_pos;
+ bin_id_400 = ebur128->i400.cache_pos;
+ bin_id_3000 = ebur128->i3000.cache_pos;
#define MOVE_TO_NEXT_CACHED_ENTRY(time) do { \
ebur128->i##time.cache_pos++; \
@@ -671,46 +719,180 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
MOVE_TO_NEXT_CACHED_ENTRY(400);
MOVE_TO_NEXT_CACHED_ENTRY(3000);
+
+#if HAVE_AVX2_EXTERNAL && HAVE_AVX2
+ // Performs filter computation in parallel for the first 4 channels of the audio file
+ for (ch = 0; ch < MIN(4,nb_channels); ch++) {
+ if (ebur128->peak_mode & PEAK_MODE_SAMPLES_PEAKS){
+ ebur128->sample_peaks[ch] = FFMAX(ebur128->sample_peaks[0], fabs(samples[idx_insample * nb_channels ]));
+ }
+ bin[ch] = samples[idx_insample * nb_channels +ch ];
+ }
+
+ // Initialise x0
+ x0 = _mm256_setr_pd(bin[0],bin[1], bin[2],bin[3]);
+ y2 = y1;
+ y1 = y0;
+ y0 = _mm256_fmadd_pd(x0,pre_b_0,_mm256_fmadd_pd(x1,pre_b_1,_mm256_fmadd_pd(x2,pre_b_2,_mm256_fnmsub_pd(y1,pre_a_1,_mm256_mul_pd(y2,pre_a_2)))));
+
+
+ x2 = x1;
+ x1 = x0;
+
+ z2 = z1;
+ z1 = z0;
+
+ z0 = _mm256_fmadd_pd(y0,rlb_b_0,_mm256_fmadd_pd(y1,rlb_b_1,_mm256_fmadd_pd(y2,rlb_b_2,_mm256_fnmsub_pd(z1,rlb_a_1,_mm256_mul_pd(z2,rlb_a_2)))));
+
+
+ // Retrieve the filtered values stored in Z0, bin[i] gets the value corresponding to the channel i
+ _mm256_store_pd(bin, _mm256_mul_pd(z0, z0));
+
+
+
+ /**
+ * Add the new value, and limit the sum to the cache size (400ms or 3s)
+ * by removing the oldest one
+ * update sum and cache, demanding on the number of channel
+ */
+ switch(nb_channels){
+ case 1:
+
+ ebur128->i400.sum [0] = ebur128->i400.sum [0] + bin[0] - ebur128->i400.cache [0][bin_id_400];
+ ebur128->i3000.sum[0] = ebur128->i3000.sum[0] + bin[0] - ebur128->i3000.cache[0][bin_id_3000];
+ ebur128->i400.cache [0][bin_id_400 ] = bin[0];
+ ebur128->i3000.cache[0][bin_id_3000] = bin[0];
+ break;
+ case 2:
+
+ ebur128->i400.sum [0] = ebur128->i400.sum [0] + bin[0] - ebur128->i400.cache [0][bin_id_400];
+ ebur128->i3000.sum[0] = ebur128->i3000.sum[0] + bin[0] - ebur128->i3000.cache[0][bin_id_3000];
+
+ ebur128->i400.cache [0][bin_id_400 ] = bin[0];
+ ebur128->i3000.cache[0][bin_id_3000] = bin[0];
+
+ ebur128->i400.sum [1] = ebur128->i400.sum [1] + bin[1] - ebur128->i400.cache [1][bin_id_400];
+ ebur128->i3000.sum[1] = ebur128->i3000.sum[1] + bin[1] - ebur128->i3000.cache[1][bin_id_3000];
- for (ch = 0; ch < nb_channels; ch++) {
- double bin;
+ ebur128->i400.cache [1][bin_id_400 ] = bin[1];
+ ebur128->i3000.cache[1][bin_id_3000] = bin[1];
+ break;
+
+ case 3:
+
+ ebur128->i400.sum [0] = ebur128->i400.sum [0] + bin[0] - ebur128->i400.cache [0][bin_id_400];
+ ebur128->i3000.sum[0] = ebur128->i3000.sum[0] + bin[0] - ebur128->i3000.cache[0][bin_id_3000];
+ ebur128->i400.cache [0][bin_id_400 ] = bin[0];
+ ebur128->i3000.cache[0][bin_id_3000] = bin[0];
+
+ ebur128->i400.sum [1] = ebur128->i400.sum [1] + bin[1] - ebur128->i400.cache [1][bin_id_400];
+ ebur128->i3000.sum[1] = ebur128->i3000.sum[1] + bin[1] - ebur128->i3000.cache[1][bin_id_3000];
+ ebur128->i400.cache [1][bin_id_400 ] = bin[1];
+ ebur128->i3000.cache[1][bin_id_3000] = bin[1];
+
+ ebur128->i400.sum [2] = ebur128->i400.sum [2] + bin[2] - ebur128->i400.cache [2][bin_id_400];
+ ebur128->i3000.sum[2] = ebur128->i3000.sum[2] + bin[2] - ebur128->i3000.cache[2][bin_id_3000];
+ ebur128->i400.cache [2][bin_id_400 ] = bin[2];
+ ebur128->i3000.cache[2][bin_id_3000] = bin[2];
+ break;
+
+ default :
+ ebur128->i400.sum[0] = ebur128->i400.sum [0] + bin[0] - ebur128->i400.cache [0][bin_id_400];
+ ebur128->i3000.sum[0] = ebur128->i3000.sum[0] + bin[0] - ebur128->i3000.cache[0][bin_id_3000];
+ ebur128->i400.cache[0][bin_id_400 ] = bin[0];
+ ebur128->i3000.cache[0][bin_id_3000] = bin[0];
+
+ ebur128->i400.sum[1] = ebur128->i400.sum [1] + bin[1] - ebur128->i400.cache [1][bin_id_400];
+ ebur128->i3000.sum[1] = ebur128->i3000.sum[1] + bin[1] - ebur128->i3000.cache[1][bin_id_3000];
+ ebur128->i400.cache[1][bin_id_400 ] = bin[1];
+ ebur128->i3000.cache[1][bin_id_3000] = bin[1];
+
+ ebur128->i400.sum[2] = ebur128->i400.sum [2] + bin[2] - ebur128->i400.cache [2][bin_id_400];
+ ebur128->i3000.sum[2] = ebur128->i3000.sum[2] + bin[2] - ebur128->i3000.cache[2][bin_id_3000];
+ ebur128->i400.cache[2][bin_id_400 ] = bin[2];
+ ebur128->i3000.cache[2][bin_id_3000] = bin[2];
+
+ ebur128->i400.sum[3] = ebur128->i400.sum [3] + bin[3] - ebur128->i400.cache [3][bin_id_400];
+ ebur128->i3000.sum[3] = ebur128->i3000.sum[3] + bin[3] - ebur128->i3000.cache[3][bin_id_3000];
+ ebur128->i400.cache [3][bin_id_400 ] = bin[3];
+ ebur128->i3000.cache[3][bin_id_3000] = bin[3];
+ break;
+ }
+ // Use the classic version to compute data from the remainings channels
+ for (ch = 4; ch < nb_channels; ch++) {
+ double bin2;
if (ebur128->peak_mode & PEAK_MODE_SAMPLES_PEAKS)
ebur128->sample_peaks[ch] = FFMAX(ebur128->sample_peaks[ch], fabs(samples[idx_insample * nb_channels + ch]));
ebur128->x[ch * 3] = samples[idx_insample * nb_channels + ch]; // set X[i]
-
if (!ebur128->ch_weighting[ch])
continue;
+
+ #define FILTER(Y, X, NUM, DEN) do { \
+ double *dst = ebur128->Y + ch*3; \
+ double *src = ebur128->X + ch*3; \
+ dst[2] = dst[1]; \
+ dst[1] = dst[0]; \
+ dst[0] = src[0]*NUM[0] + src[1]*NUM[1] + src[2]*NUM[2] \
+ - dst[1]*DEN[1] - dst[2]*DEN[2]; \
+ } while (0)
+
+ // TODO: merge both filters in one?
+ FILTER(y, x, ebur128->pre_b, ebur128->pre_a); // apply pre-filter
+ ebur128->x[ch * 3 + 2] = ebur128->x[ch * 3 + 1];
+ ebur128->x[ch * 3 + 1] = ebur128->x[ch * 3 ];
+ FILTER(z, y, ebur128->rlb_b, ebur128->rlb_a); // apply RLB-filter
+
+ bin2 = ebur128->z[ch * 3] * ebur128->z[ch * 3];
+
+ /* Add the new value, and limit the sum to the cache size (400ms or 3s)
+ * by removing the oldest one */
+ ebur128->i400.sum [ch] = ebur128->i400.sum [ch] + bin2 - ebur128->i400.cache [ch][bin_id_400];
+ ebur128->i3000.sum[ch] = ebur128->i3000.sum[ch] + bin2 - ebur128->i3000.cache[ch][bin_id_3000];
+
+ // Override old cache entry with the new value
+ ebur128->i400.cache [ch][bin_id_400 ] = bin2;
+ ebur128->i3000.cache[ch][bin_id_3000] = bin2;
+ }
- /* Y[i] = X[i]*b0 + X[i-1]*b1 + X[i-2]*b2 - Y[i-1]*a1 - Y[i-2]*a2 */
-#define FILTER(Y, X, NUM, DEN) do { \
- double *dst = ebur128->Y + ch*3; \
- double *src = ebur128->X + ch*3; \
- dst[2] = dst[1]; \
- dst[1] = dst[0]; \
- dst[0] = src[0]*NUM[0] + src[1]*NUM[1] + src[2]*NUM[2] \
- - dst[1]*DEN[1] - dst[2]*DEN[2]; \
-} while (0)
-
- // TODO: merge both filters in one?
- FILTER(y, x, ebur128->pre_b, ebur128->pre_a); // apply pre-filter
- ebur128->x[ch * 3 + 2] = ebur128->x[ch * 3 + 1];
- ebur128->x[ch * 3 + 1] = ebur128->x[ch * 3 ];
- FILTER(z, y, ebur128->rlb_b, ebur128->rlb_a); // apply RLB-filter
+#else
- bin = ebur128->z[ch * 3] * ebur128->z[ch * 3];
+ for (ch = 0; ch < nb_channels; ch++) {
+ double bin;
+ if (ebur128->peak_mode & PEAK_MODE_SAMPLES_PEAKS)
+ ebur128->sample_peaks[ch] = FFMAX(ebur128->sample_peaks[ch], fabs(samples[idx_insample * nb_channels + ch]));
- /* add the new value, and limit the sum to the cache size (400ms or 3s)
- * by removing the oldest one */
- ebur128->i400.sum [ch] = ebur128->i400.sum [ch] + bin - ebur128->i400.cache [ch][bin_id_400];
- ebur128->i3000.sum[ch] = ebur128->i3000.sum[ch] + bin - ebur128->i3000.cache[ch][bin_id_3000];
+ ebur128->x[ch * 3] = samples[idx_insample * nb_channels + ch]; // Set X[i]
- /* override old cache entry with the new value */
- ebur128->i400.cache [ch][bin_id_400 ] = bin;
- ebur128->i3000.cache[ch][bin_id_3000] = bin;
+ if (!ebur128->ch_weighting[ch])
+ continue;
+
+ #define FILTER(Y, X, NUM, DEN) do { \
+ double *dst = ebur128->Y + ch*3; \
+ double *src = ebur128->X + ch*3; \
+ dst[2] = dst[1]; \
+ dst[1] = dst[0]; \
+ dst[0] = src[0]*NUM[0] + src[1]*NUM[1] + src[2]*NUM[2] \
+ - dst[1]*DEN[1] - dst[2]*DEN[2]; \
+ } while (0)
+
+ // TODO: merge both filters in one?
+ FILTER(y, x, ebur128->pre_b, ebur128->pre_a); // Apply pre-filter
+ ebur128->x[ch * 3 + 2] = ebur128->x[ch * 3 + 1];
+ ebur128->x[ch * 3 + 1] = ebur128->x[ch * 3 ];
+ FILTER(z, y, ebur128->rlb_b, ebur128->rlb_a); // Apply RLB-filter
+ bin = ebur128->z[ch * 3] * ebur128->z[ch * 3];
+ /* Add the new value, and limit the sum to the cache size (400ms or 3s)
+ * by removing the oldest one */
+ ebur128->i400.sum [ch] = ebur128->i400.sum [ch] + bin - ebur128->i400.cache [ch][bin_id_400];
+ ebur128->i3000.sum[ch] = ebur128->i3000.sum[ch] + bin - ebur128->i3000.cache[ch][bin_id_3000];
+ // Override old cache entry with the new value
+ ebur128->i400.cache [ch][bin_id_400 ] = bin;
+ ebur128->i3000.cache[ch][bin_id_3000] = bin;
}
-
+#endif
+
#define FIND_PEAK(global, sp, ptype) do { \
int ch; \
double maxpeak; \
--
2.49.0
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [FFmpeg-devel] [PATCH] libavfilter/ebur128: SIMD optimization
2025-04-17 14:33 [FFmpeg-devel] [PATCH] libavfilter/ebur128: SIMD optimization gkhayat
@ 2025-04-17 17:07 ` Andreas Rheinhardt
2025-04-17 17:10 ` James Almer
0 siblings, 1 reply; 4+ messages in thread
From: Andreas Rheinhardt @ 2025-04-17 17:07 UTC (permalink / raw)
To: ffmpeg-devel
gkhayat@spectre-music.com:
> From: Guillaume Khayat <gkhayat@spectre-music.com>
>
> Improve performance (+17%) of ebur_128 filter using AVX2 and FMA instruction in the body of the filter_frame function.
>
> ## Benchmark
>
> Tested with hyperfine
>
> hyperfine --warmup 2 "./ffmpeg_reference -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -" "./ffmpeg_avx -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -"
> Benchmark 1: ./ffmpeg_reference -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -
> Time (mean ± σ): 7.118 s ± 0.037 s [User: 9.114 s, System: 1.038 s]
> Range (min … max): 7.073 s … 7.177 s 10 runs
>
> Benchmark 2: ./ffmpeg_avx -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -
> Time (mean ± σ): 6.073 s ± 0.108 s [User: 7.903 s, System: 1.058 s]
> Range (min … max): 5.955 s … 6.327 s 10 runs
>
> Summary
> ./ffmpeg_avx -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null - ran
> 1.17 ± 0.02 times faster than ./ffmpeg_reference -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -
>
> ## Tests
>
> - all FATE tests pass, tested on Darwin/arm64 and Linux/x86_64 w/ AVX2/FMA support
> - On AVX2/FMA-capable system, all test files from the EBU yield the exact same output values (I/LRA) after and before optimization. See https://tech.ebu.ch/publications/ebu_loudness_test_set
>
> Disclaimer: this is my first ever patch submission to FFmpeg, and first ever time using git send-email to submit a patch anywhere.
>
> Signed-off-by: Cesar Matheus <cesar.matheus@telecom-paris.fr>
> Signed-off-by: Guillaume Khayat <gkhayat@spectre-music.com>
> ---
> libavfilter/f_ebur128.c | 246 ++++++++++++++++++++++++++++++++++------
> 1 file changed, 214 insertions(+), 32 deletions(-)
>
> diff --git a/libavfilter/f_ebur128.c b/libavfilter/f_ebur128.c
> index 768f062bac..e305b0a3ce 100644
> --- a/libavfilter/f_ebur128.c
> +++ b/libavfilter/f_ebur128.c
> @@ -28,7 +28,7 @@
>
> #include <float.h>
> #include <math.h>
> -
> +#include "libavutil/intmath.h"
> #include "libavutil/avassert.h"
> #include "libavutil/channel_layout.h"
> #include "libavutil/dict.h"
> @@ -199,7 +199,7 @@ static const AVOption ebur128_options[] = {
> };
>
> AVFILTER_DEFINE_CLASS(ebur128);
> -
> +#define MIN(a, b) ((a) < (b) ? (a) : (b))
> static const uint8_t graph_colors[] = {
> 0xdd, 0x66, 0x66, // value above 1LU non reached below -1LU (impossible)
> 0x66, 0x66, 0xdd, // value below 1LU non reached below -1LU
> @@ -628,13 +628,61 @@ static int gate_update(struct integrator *integ, double power,
>
> static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
> {
> - int i, ch, idx_insample, ret;
> +
> + int i, ch, idx_insample, ret,bin_id_400,bin_id_3000;
> AVFilterContext *ctx = inlink->dst;
> EBUR128Context *ebur128 = ctx->priv;
> const int nb_channels = ebur128->nb_channels;
> const int nb_samples = insamples->nb_samples;
> const double *samples = (double *)insamples->data[0];
> AVFrame *pic;
> +
> +#if HAVE_AVX2_EXTERNAL && HAVE_AVX2
This is completely wrong: This only checks whether your assembler
supports AVX2 and whether it was not disabled in configure. But this
does not imply that the CPU where this code runs is actually capable of
AVX2; I don't even know whether this check ensures that the compiler
understands __m256d.
For actual runtime support you need to check via av_get_cpu_flags(). See
how other DSP code does it.
- Andreas
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* Re: [FFmpeg-devel] [PATCH] libavfilter/ebur128: SIMD optimization
2025-04-17 17:07 ` Andreas Rheinhardt
@ 2025-04-17 17:10 ` James Almer
2025-04-18 7:26 ` Guillaume Khayat
0 siblings, 1 reply; 4+ messages in thread
From: James Almer @ 2025-04-17 17:10 UTC (permalink / raw)
To: ffmpeg-devel
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On 4/17/2025 2:07 PM, Andreas Rheinhardt wrote:
> gkhayat@spectre-music.com:
>> From: Guillaume Khayat <gkhayat@spectre-music.com>
>>
>> Improve performance (+17%) of ebur_128 filter using AVX2 and FMA instruction in the body of the filter_frame function.
>>
>> ## Benchmark
>>
>> Tested with hyperfine
>>
>> hyperfine --warmup 2 "./ffmpeg_reference -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -" "./ffmpeg_avx -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -"
>> Benchmark 1: ./ffmpeg_reference -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -
>> Time (mean ± σ): 7.118 s ± 0.037 s [User: 9.114 s, System: 1.038 s]
>> Range (min … max): 7.073 s … 7.177 s 10 runs
>>
>> Benchmark 2: ./ffmpeg_avx -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -
>> Time (mean ± σ): 6.073 s ± 0.108 s [User: 7.903 s, System: 1.058 s]
>> Range (min … max): 5.955 s … 6.327 s 10 runs
>>
>> Summary
>> ./ffmpeg_avx -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null - ran
>> 1.17 ± 0.02 times faster than ./ffmpeg_reference -i ~/test.wav -vn -af ebur128=peak=none:framelog=quiet -f null -
>>
>> ## Tests
>>
>> - all FATE tests pass, tested on Darwin/arm64 and Linux/x86_64 w/ AVX2/FMA support
>> - On AVX2/FMA-capable system, all test files from the EBU yield the exact same output values (I/LRA) after and before optimization. See https://tech.ebu.ch/publications/ebu_loudness_test_set
>>
>> Disclaimer: this is my first ever patch submission to FFmpeg, and first ever time using git send-email to submit a patch anywhere.
>>
>> Signed-off-by: Cesar Matheus <cesar.matheus@telecom-paris.fr>
>> Signed-off-by: Guillaume Khayat <gkhayat@spectre-music.com>
>> ---
>> libavfilter/f_ebur128.c | 246 ++++++++++++++++++++++++++++++++++------
>> 1 file changed, 214 insertions(+), 32 deletions(-)
>>
>> diff --git a/libavfilter/f_ebur128.c b/libavfilter/f_ebur128.c
>> index 768f062bac..e305b0a3ce 100644
>> --- a/libavfilter/f_ebur128.c
>> +++ b/libavfilter/f_ebur128.c
>> @@ -28,7 +28,7 @@
>>
>> #include <float.h>
>> #include <math.h>
>> -
>> +#include "libavutil/intmath.h"
>> #include "libavutil/avassert.h"
>> #include "libavutil/channel_layout.h"
>> #include "libavutil/dict.h"
>> @@ -199,7 +199,7 @@ static const AVOption ebur128_options[] = {
>> };
>>
>> AVFILTER_DEFINE_CLASS(ebur128);
>> -
>> +#define MIN(a, b) ((a) < (b) ? (a) : (b))
>> static const uint8_t graph_colors[] = {
>> 0xdd, 0x66, 0x66, // value above 1LU non reached below -1LU (impossible)
>> 0x66, 0x66, 0xdd, // value below 1LU non reached below -1LU
>> @@ -628,13 +628,61 @@ static int gate_update(struct integrator *integ, double power,
>>
>> static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
>> {
>> - int i, ch, idx_insample, ret;
>> +
>> + int i, ch, idx_insample, ret,bin_id_400,bin_id_3000;
>> AVFilterContext *ctx = inlink->dst;
>> EBUR128Context *ebur128 = ctx->priv;
>> const int nb_channels = ebur128->nb_channels;
>> const int nb_samples = insamples->nb_samples;
>> const double *samples = (double *)insamples->data[0];
>> AVFrame *pic;
>> +
>> +#if HAVE_AVX2_EXTERNAL && HAVE_AVX2
>
> This is completely wrong: This only checks whether your assembler
> supports AVX2 and whether it was not disabled in configure. But this
> does not imply that the CPU where this code runs is actually capable of
> AVX2; I don't even know whether this check ensures that the compiler
> understands __m256d.
> For actual runtime support you need to check via av_get_cpu_flags(). See
> how other DSP code does it.
>
> - Andreas
This also needs to be written in NASM syntax assembly, not Intel
intrinsics, and it should be in a separate file in the x86/ folder,
using function pointers like every other SIMD implementation.
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [FFmpeg-devel] [PATCH] libavfilter/ebur128: SIMD optimization
2025-04-17 17:10 ` James Almer
@ 2025-04-18 7:26 ` Guillaume Khayat
0 siblings, 0 replies; 4+ messages in thread
From: Guillaume Khayat @ 2025-04-18 7:26 UTC (permalink / raw)
To: FFmpeg development discussions and patches
Thank you for the feedback.
OK I understand. We’ll do that.
Guillaume
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^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-04-18 7:27 UTC | newest]
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2025-04-17 14:33 [FFmpeg-devel] [PATCH] libavfilter/ebur128: SIMD optimization gkhayat
2025-04-17 17:07 ` Andreas Rheinhardt
2025-04-17 17:10 ` James Almer
2025-04-18 7:26 ` Guillaume Khayat
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