From 5dd35b43f1cd3dddaddaae8e2f267117b5fa2d54 Mon Sep 17 00:00:00 2001 From: Anton Khirnov Date: Fri, 21 Oct 2011 11:47:39 +0200 Subject: Move timefilter code from lavf to lavd. It's only used in the JACK device. Fixes linking shared lavd with JACK enabled. --- libavdevice/Makefile | 4 +- libavdevice/jack_audio.c | 2 +- libavdevice/timefilter.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++ libavdevice/timefilter.h | 97 ++++++++++++++++++++++++++++++ 4 files changed, 252 insertions(+), 2 deletions(-) create mode 100644 libavdevice/timefilter.c create mode 100644 libavdevice/timefilter.h (limited to 'libavdevice') diff --git a/libavdevice/Makefile b/libavdevice/Makefile index d8a5945549..1f2a6efceb 100644 --- a/libavdevice/Makefile +++ b/libavdevice/Makefile @@ -13,7 +13,7 @@ OBJS-$(CONFIG_ALSA_OUTDEV) += alsa-audio-common.o \ OBJS-$(CONFIG_BKTR_INDEV) += bktr.o OBJS-$(CONFIG_DV1394_INDEV) += dv1394.o OBJS-$(CONFIG_FBDEV_INDEV) += fbdev.o -OBJS-$(CONFIG_JACK_INDEV) += jack_audio.o +OBJS-$(CONFIG_JACK_INDEV) += jack_audio.o timefilter.o OBJS-$(CONFIG_OSS_INDEV) += oss_audio.o OBJS-$(CONFIG_OSS_OUTDEV) += oss_audio.o OBJS-$(CONFIG_SNDIO_INDEV) += sndio_common.o sndio_dec.o @@ -30,4 +30,6 @@ OBJS-$(CONFIG_LIBDC1394_INDEV) += libdc1394.o SKIPHEADERS-$(HAVE_ALSA_ASOUNDLIB_H) += alsa-audio.h SKIPHEADERS-$(HAVE_SNDIO_H) += sndio_common.h +TESTPROGS = timefilter + include $(SRC_PATH)/subdir.mak diff --git a/libavdevice/jack_audio.c b/libavdevice/jack_audio.c index 4907e82395..f75c176be9 100644 --- a/libavdevice/jack_audio.c +++ b/libavdevice/jack_audio.c @@ -29,7 +29,7 @@ #include "libavutil/opt.h" #include "libavcodec/avcodec.h" #include "libavformat/avformat.h" -#include "libavformat/timefilter.h" +#include "timefilter.h" /** * Size of the internal FIFO buffers as a number of audio packets diff --git a/libavdevice/timefilter.c b/libavdevice/timefilter.c new file mode 100644 index 0000000000..332d33b5e8 --- /dev/null +++ b/libavdevice/timefilter.c @@ -0,0 +1,151 @@ +/* + * Delay Locked Loop based time filter + * Copyright (c) 2009 Samalyse + * Copyright (c) 2009 Michael Niedermayer + * Author: Olivier Guilyardi + * Michael Niedermayer + * + * This file is part of Libav. + * + * Libav is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * Libav is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with Libav; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + + +#include "config.h" +#include "timefilter.h" +#include "libavutil/mem.h" + +struct TimeFilter { + /// Delay Locked Loop data. These variables refer to mathematical + /// concepts described in: http://www.kokkinizita.net/papers/usingdll.pdf + double cycle_time; + double feedback2_factor; + double feedback3_factor; + double clock_period; + int count; +}; + +TimeFilter * ff_timefilter_new(double clock_period, double feedback2_factor, double feedback3_factor) +{ + TimeFilter *self = av_mallocz(sizeof(TimeFilter)); + self->clock_period = clock_period; + self->feedback2_factor = feedback2_factor; + self->feedback3_factor = feedback3_factor; + return self; +} + +void ff_timefilter_destroy(TimeFilter *self) +{ + av_freep(&self); +} + +void ff_timefilter_reset(TimeFilter *self) +{ + self->count = 0; +} + +double ff_timefilter_update(TimeFilter *self, double system_time, double period) +{ + self->count++; + if (self->count==1) { + /// init loop + self->cycle_time = system_time; + } else { + double loop_error; + self->cycle_time += self->clock_period * period; + /// calculate loop error + loop_error = system_time - self->cycle_time; + + /// update loop + self->cycle_time += FFMAX(self->feedback2_factor, 1.0/(self->count)) * loop_error; + self->clock_period += self->feedback3_factor * loop_error / period; + } + return self->cycle_time; +} + +#ifdef TEST +#include "libavutil/lfg.h" +#define LFG_MAX ((1LL << 32) - 1) + +#undef printf + +int main(void) +{ + AVLFG prng; + double n0,n1; +#define SAMPLES 1000 + double ideal[SAMPLES]; + double samples[SAMPLES]; +#if 1 + for(n0= 0; n0<40; n0=2*n0+1){ + for(n1= 0; n1<10; n1=2*n1+1){ +#else + {{ + n0=7; + n1=1; +#endif + double best_error= 1000000000; + double bestpar0=1; + double bestpar1=0.001; + int better, i; + + av_lfg_init(&prng, 123); + for(i=0; i + * Michael Niedermayer + * + * This file is part of Libav. + * + * Libav is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * Libav is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with Libav; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef AVDEVICE_TIMEFILTER_H +#define AVDEVICE_TIMEFILTER_H + +/** + * Opaque type representing a time filter state + * + * The purpose of this filter is to provide a way to compute accurate time + * stamps that can be compared to wall clock time, especially when dealing + * with two clocks: the system clock and a hardware device clock, such as + * a soundcard. + */ +typedef struct TimeFilter TimeFilter; + + +/** + * Create a new Delay Locked Loop time filter + * + * feedback2_factor and feedback3_factor are the factors used for the + * multiplications that are respectively performed in the second and third + * feedback paths of the loop. + * + * Unless you know what you are doing, you should set these as follow: + * + * o = 2 * M_PI * bandwidth * period + * feedback2_factor = sqrt(2 * o) + * feedback3_factor = o * o + * + * Where bandwidth is up to you to choose. Smaller values will filter out more + * of the jitter, but also take a longer time for the loop to settle. A good + * starting point is something between 0.3 and 3 Hz. + * + * @param clock_period period of the hardware clock in seconds + * (for example 1.0/44100) + * + * For more details about these parameters and background concepts please see: + * http://www.kokkinizita.net/papers/usingdll.pdf + */ +TimeFilter * ff_timefilter_new(double clock_period, double feedback2_factor, double feedback3_factor); + +/** + * Update the filter + * + * This function must be called in real time, at each process cycle. + * + * @param period the device cycle duration in clock_periods. For example, at + * 44.1kHz and a buffer size of 512 frames, period = 512 when clock_period + * was 1.0/44100, or 512/44100 if clock_period was 1. + * + * system_time, in seconds, should be the value of the system clock time, + * at (or as close as possible to) the moment the device hardware interrupt + * occured (or any other event the device clock raises at the beginning of a + * cycle). + * + * @return the filtered time, in seconds + */ +double ff_timefilter_update(TimeFilter *self, double system_time, double period); + +/** + * Reset the filter + * + * This function should mainly be called in case of XRUN. + * + * Warning: after calling this, the filter is in an undetermined state until + * the next call to ff_timefilter_update() + */ +void ff_timefilter_reset(TimeFilter *); + +/** + * Free all resources associated with the filter + */ +void ff_timefilter_destroy(TimeFilter *); + +#endif /* AVDEVICE_TIMEFILTER_H */ -- cgit v1.2.3