[pulseaudio-discuss] [PATCH v3 20/24] echo-cancel: Add beamforming support in the webrtc canceller
Tanu Kaskinen
tanuk at iki.fi
Mon Feb 15 11:12:32 UTC 2016
On Mon, 2016-01-18 at 13:06 +0530, arun at accosted.net wrote:
> From: Arun Raghavan <git at arunraghavan.net>
>
> ---
> src/modules/echo-cancel/webrtc.cc | 138 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 137 insertions(+), 1 deletion(-)
>
> diff --git a/src/modules/echo-cancel/webrtc.cc b/src/modules/echo-cancel/webrtc.cc
> index 5f00286..9ae5d77 100644
> --- a/src/modules/echo-cancel/webrtc.cc
> +++ b/src/modules/echo-cancel/webrtc.cc
> @@ -52,6 +52,7 @@ PA_C_DECL_END
> #define DEFAULT_INTELLIGIBILITY_ENHANCER false
> #define DEFAULT_EXPERIMENTAL_AGC false
> #define DEFAULT_AGC_START_VOLUME 85
> +#define DEFAULT_BEAMFORMING false
> #define DEFAULT_TRACE false
>
> #define WEBRTC_AGC_MAX_VOLUME 255
> @@ -70,6 +71,9 @@ static const char* const valid_modargs[] = {
> "intelligibility_enhancer",
> "experimental_agc",
> "agc_start_volume",
> + "beamforming",
> + "mic_geometry", /* documented in parse_mic_geometry() */
> + "target_direction", /* documented in parse_mic_geometry() */
> "trace",
> NULL
> };
> @@ -138,6 +142,76 @@ static void pa_webrtc_ec_fixate_spec(pa_sample_spec *rec_ss, pa_channel_map *rec
> play_ss->rate = rec_ss->rate;
> }
>
> +static bool parse_point(const char **point, float (&f)[3]) {
> + int ret, length;
> +
> + ret = sscanf(*point, "%g,%g,%g%n", &f[0], &f[1], &f[2], &length);
> + if (ret != 3)
> + return false;
> +
> + /* Consume the bytes we've read so far */
> + *point += length;
> +
> + /* Consume trailing comma if there is one */
> + if (**point == ',')
> + (*point)++;
I don't think this should be done in this function. When expecting only
one point, we should fail on "1,2,3," but this code accepts that
string.
> +
> + return true;
> +}
> +
> +static bool parse_mic_geometry(const char **mic_geometry, std::vector& geometry) {
> + /* The microphone geometry is expressed as cartesian point form:
> + * x1,y1,z1,x2,y2,z2,...
> + *
> + * Where x1,y1,z1 is the position of the first microphone with regards to
> + * the array's "center", x2,y2,z2 the position of the second, and so on.
> + *
> + * 'x' is the horizontal coordinate, with positive values being to the
> + * right from the mic array's perspective.
> + *
> + * 'y' is the depth coordinate, with positive values being in front of the
> + * array.
> + *
> + * 'z' is the vertical coordinate, with positive values being above the
> + * array.
> + *
> + * All distances are in meters.
> + */
It's a bit unclear what "the mic array's perspective" means. Should I
imagine the array as a person standing upright, looking straight ahead?
Then positive x is to the right from the "person's" point of view,
positive y is in front of the array guy and positive z is above the
array.
> +
> + /* The target direction is expected to be in spherical point form:
> + * a,e,r
> + *
> + * Where 'a is the azimuth of the first mic channel, 'e' its elevation,
> + * and 'r' the radius.
> + *
> + * 0 radians azimuth is to the right of the array, and positive angles
> + * move in a counter-clockwise direction.
> + *
> + * 0 radians elevation is horizontal w.r.t. the array, and positive
> + * angles go upwards.
> + *
> + * radius is distance from the array center in meters.
> + */
> +
> + int i;
> + float f[3];
> +
> + for (i = 0; i < geometry.size(); i++) {
> + if (!parse_point(mic_geometry, f)) {
> + pa_log("Failed to parse channel %d in mic_geometry", i);
> + return false;
> + }
> +
> + pa_log_debug("Got mic #%d position: (%g, %g, %g)", i, f[0], f[1], f[2]);
> +
> + geometry[i].c[0] = f[0];
> + geometry[i].c[1] = f[1];
> + geometry[i].c[2] = f[2];
> + }
> +
> + return true;
> +}
> +
> bool pa_webrtc_ec_init(pa_core *c, pa_echo_canceller *ec,
> pa_sample_spec *rec_ss, pa_channel_map *rec_map,
> pa_sample_spec *play_ss, pa_channel_map *play_map,
> @@ -146,7 +220,7 @@ bool pa_webrtc_ec_init(pa_core *c, pa_echo_canceller *ec,
> webrtc::AudioProcessing *apm = NULL;
> webrtc::ProcessingConfig pconfig;
> webrtc::Config config;
> - bool hpf, ns, agc, dgc, mobile, cn, vad, ext_filter, intelligibility, experimental_agc;
> + bool hpf, ns, agc, dgc, mobile, cn, vad, ext_filter, intelligibility, experimental_agc, beamforming;
> int rm = -1;
> uint32_t agc_start_volume;
> pa_modargs *ma;
> @@ -255,6 +329,12 @@ bool pa_webrtc_ec_init(pa_core *c, pa_echo_canceller *ec,
> }
> ec->params.webrtc.agc_start_volume = agc_start_volume;
>
> + beamforming = DEFAULT_BEAMFORMING;
> + if (pa_modargs_get_value_boolean(ma, "beamforming", &beamforming) < 0) {
> + pa_log("Failed to parse beamforming value");
> + goto fail;
> + }
> +
> if (ext_filter)
> config.Set(new webrtc::ExtendedFilter(true));
> if (intelligibility)
> @@ -276,6 +356,62 @@ bool pa_webrtc_ec_init(pa_core *c, pa_echo_canceller *ec,
>
> pa_webrtc_ec_fixate_spec(rec_ss, rec_map, play_ss, play_map, out_ss, out_map);
>
> + /* We do this after fixate because we need the capture channel count */
> + if (beamforming) {
> + std::vector geometry(rec_ss->channels);
> + webrtc::SphericalPointf direction(0.0f, 0.0f, 0.0f);
> + const char *mic_geometry, *target_direction;
> +
> + if (!(mic_geometry = pa_modargs_get_value(ma, "mic_geometry", NULL))) {
> + pa_log("mic_geometry must be set if beamforming is enabled");
> + goto fail;
> + }
> +
> + if (!parse_mic_geometry(&mic_geometry, geometry)) {
> + pa_log("Failed to parse mic_geometry value");
> + goto fail;
> + }
> +
> + if (*mic_geometry != '\0') {
> + pa_log("Failed to parse mic_geometry value: more parameters than expected");
> + goto fail;
> + }
This check could be moved to parse_mic_geometry().
> +
> + if ((target_direction = pa_modargs_get_value(ma, "target_direction", NULL))) {
> + float f[3];
> +
> + if (!parse_point(&target_direction, f)) {
> + pa_log("Failed to parse target_direction value");
> + goto fail;
> + }
> +
> + if (*target_direction != '\0') {
> + pa_log("Failed to parse target_direction value: more parameters than expected");
> + goto fail;
> + }
> +
> +#define IS_ZERO(f) ((f) < 0.000001 && (f) > -0.000001)
This kind of macro would be nice to have in some shared location.
speex.c and a couple of tests have similar code, and I remember needing
it in the volume control patches.
> +
> + if (!IS_ZERO(f[1]) || !IS_ZERO(f[2])) {
This line contains a tab character.
> + pa_log("The beamformer currently only supports targeting along the azimuth");
> + goto fail;
> + }
> +
> + direction.s[0] = f[0];
> + direction.s[1] = f[1];
> + direction.s[2] = f[2];
> + }
> +
> + /* The beamformer gives us a single channel */
> + out_ss->channels = 1;
> + pa_channel_map_init_mono(out_map);
Could this be moved to fixate_spec()? I don't like the audio format
parameters being calculated all over the place.
--
Tanu
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