From: Sebastian Dröge Date: Mon, 11 Sep 2017 19:49:32 +0000 (+0300) Subject: audio: Add helper object for audio discontinuity detection and sample alignment X-Git-Tag: 1.19.3~511^2~2131 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ec1e20ffe5c160f92ecec2d122d1e21b258471c3;p=platform%2Fupstream%2Fgstreamer.git audio: Add helper object for audio discontinuity detection and sample alignment This is the same code that is in decklinkaudiosrc, audioringbuffer, audiomixer and various other places. Have it once instead of copying it everywhere. https://bugzilla.gnome.org/show_bug.cgi?id=787560 --- diff --git a/docs/libs/gst-plugins-base-libs-sections.txt b/docs/libs/gst-plugins-base-libs-sections.txt index de28e4e..1e3190e 100644 --- a/docs/libs/gst-plugins-base-libs-sections.txt +++ b/docs/libs/gst-plugins-base-libs-sections.txt @@ -244,6 +244,19 @@ GST_AUDIO_RESAMPLER_QUALITY_DEFAULT GST_AUDIO_RESAMPLER_QUALITY_MAX GST_AUDIO_RESAMPLER_QUALITY_MIN +GstAudioStreamAlign +gst_audio_stream_align_new +gst_audio_stream_align_copy +gst_audio_stream_align_free +gst_audio_stream_align_mark_discont +gst_audio_stream_align_process +gst_audio_stream_align_get_alignment_threshold +gst_audio_stream_align_set_alignment_threshold +gst_audio_stream_align_get_discont_wait +gst_audio_stream_align_set_discont_wait +gst_audio_stream_align_get_rate +gst_audio_stream_align_set_rate + GST_TYPE_BUFFER_FORMAT GST_TYPE_BUFFER_FORMAT_TYPE @@ -265,6 +278,7 @@ gst_audio_resampler_filter_interpolation_get_type gst_audio_resampler_filter_mode_get_type gst_audio_resampler_flags_get_type gst_audio_resampler_method_get_type +gst_audio_stream_align_get_type _GST_AUDIO_FORMAT_NE diff --git a/gst-libs/gst/audio/Makefile.am b/gst-libs/gst/audio/Makefile.am index e6fcde1..100867d 100644 --- a/gst-libs/gst/audio/Makefile.am +++ b/gst-libs/gst/audio/Makefile.am @@ -54,7 +54,8 @@ libgstaudio_@GST_API_VERSION@_la_SOURCES = \ gstaudiosrc.c \ gstaudioutilsprivate.c \ streamvolume.c \ - gstaudioiec61937.c + gstaudioiec61937.c \ + gstaudiostreamalign.c nodist_libgstaudio_@GST_API_VERSION@_la_SOURCES = $(BUILT_SOURCES) @@ -80,7 +81,8 @@ libgstaudio_@GST_API_VERSION@include_HEADERS = \ gstaudiosink.h \ gstaudiosrc.h \ streamvolume.h \ - gstaudioiec61937.h + gstaudioiec61937.h \ + gstaudiostreamalign.h nodist_libgstaudio_@GST_API_VERSION@include_HEADERS = \ audio-enumtypes.h diff --git a/gst-libs/gst/audio/audio.h b/gst-libs/gst/audio/audio.h index edb8136..42d112d 100644 --- a/gst-libs/gst/audio/audio.h +++ b/gst-libs/gst/audio/audio.h @@ -31,6 +31,7 @@ #include #include #include +#include G_BEGIN_DECLS diff --git a/gst-libs/gst/audio/gstaudiostreamalign.c b/gst-libs/gst/audio/gstaudiostreamalign.c new file mode 100644 index 0000000..846a03c --- /dev/null +++ b/gst-libs/gst/audio/gstaudiostreamalign.c @@ -0,0 +1,377 @@ +/* GStreamer + * Copyright (C) 2017 Sebastian Dröge + * + * gstaudiostreamalign.h: + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the + * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, + * Boston, MA 02110-1301, USA. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include "gstaudiostreamalign.h" + +/** + * SECTION:gstaudiostreamalign + * @title: GstAudioStreamAlign + * @short_description: Helper object for tracking audio stream alignment and discontinuities + * + * #GstAudioStreamAlign provides a helper object that helps tracking audio + * stream alignment and discontinuities, and detects discontinuities if + * possible. + * + * See gst_audio_stream_align_new() for a description of its parameters and + * gst_audio_stream_align_process() for the details of the processing. + */ + +G_DEFINE_BOXED_TYPE (GstAudioStreamAlign, gst_audio_stream_align, + (GBoxedCopyFunc) gst_audio_stream_align_copy, + (GBoxedFreeFunc) gst_audio_stream_align_free); + +struct _GstAudioStreamAlign +{ + gint rate; + GstClockTime alignment_threshold; + GstClockTime discont_wait; + + /* counter to keep track of timestamps */ + guint64 next_offset; + + /* Last time we noticed a discont */ + GstClockTime discont_time; +}; + +/** + * gst_audio_stream_align_new: + * @rate: a sample rate + * @alignment_threshold: a alignment threshold in nanoseconds + * @discont_wait: discont wait in nanoseconds + * + * Allocate a new #GstAudioStreamAlign with the given configuration. All + * processing happens according to sample rate @rate, until + * gst_audio_discont_wait_set_rate() is called with a new @rate. + * + * @alignment_threshold gives the tolerance in nanoseconds after which a + * timestamp difference is considered a discontinuity. Once detected, + * @discont_wait nanoseconds have to pass without going below the threshold + * again until the output buffer is marked as a discontinuity. These can later + * be re-configured with gst_audio_stream_align_set_alignment_threshold() and + * gst_audio_stream_align_set_discont_wait(). + * + * Returns: a new #GstAudioStreamAlign. free with gst_audio_stream_align_free(). + * + * Since: 1.14 + */ +GstAudioStreamAlign * +gst_audio_stream_align_new (gint rate, GstClockTime alignment_threshold, + GstClockTime discont_wait) +{ + GstAudioStreamAlign *align; + + g_return_val_if_fail (rate > 0, NULL); + + align = g_new0 (GstAudioStreamAlign, 1); + align->rate = rate; + align->alignment_threshold = alignment_threshold; + align->discont_wait = discont_wait; + + gst_audio_stream_align_mark_discont (align); + + return align; +} + +/** + * gst_audio_stream_align_copy: + * @align: a #GstAudioStreamAlign + * + * Copy a GstAudioStreamAlign structure. + * + * Returns: a new #GstAudioStreamAlign. free with gst_audio_stream_align_free. + * + * Since: 1.14 + */ +GstAudioStreamAlign * +gst_audio_stream_align_copy (const GstAudioStreamAlign * align) +{ + GstAudioStreamAlign *copy; + + g_return_val_if_fail (align != NULL, NULL); + + copy = g_new0 (GstAudioStreamAlign, 1); + *copy = *align; + + return copy; +} + +/** + * gst_audio_stream_align_free: + * @align: a #GstAudioStreamAlign + * + * Free a GstAudioStreamAlign structure previously allocated with gst_audio_stream_align_new() + * or gst_audio_stream_align_copy(). + * + * Since: 1.14 + */ +void +gst_audio_stream_align_free (GstAudioStreamAlign * align) +{ + g_return_if_fail (align != NULL); + g_free (align); +} + +/** + * gst_audio_discont_set_rate: + * @align: a #GstAudioStreamAlign + * @rate: a new sample rate + * + * Sets @rate as new sample rate for the following processing. If the sample + * rate differs this implicitely marks the next data as discontinuous. + * + * Since: 1.14 + */ +void +gst_audio_stream_align_set_rate (GstAudioStreamAlign * align, gint rate) +{ + g_return_if_fail (align != NULL); + g_return_if_fail (rate > 0); + + if (align->rate == rate) + return; + + align->rate = rate; + gst_audio_stream_align_mark_discont (align); +} + +/** + * gst_audio_discont_get_rate: + * @align: a #GstAudioStreamAlign + * + * Gets the currently configured sample rate. + * + * Returns: The currently configured sample rate + * + * Since: 1.14 + */ +gint +gst_audio_stream_align_get_rate (GstAudioStreamAlign * align) +{ + g_return_val_if_fail (align != NULL, 0); + + return align->rate; +} + +/** + * gst_audio_discont_set_alignment_threshold: + * @align: a #GstAudioStreamAlign + * @alignment_treshold: a new alignment threshold + * + * Sets @alignment_treshold as new alignment threshold for the following processing. + * + * Since: 1.14 + */ +void +gst_audio_stream_align_set_alignment_threshold (GstAudioStreamAlign * + align, GstClockTime alignment_threshold) +{ + g_return_if_fail (align != NULL); + + align->alignment_threshold = alignment_threshold; +} + +/** + * gst_audio_discont_get_alignment_threshold: + * @align: a #GstAudioStreamAlign + * + * Gets the currently configured alignment threshold. + * + * Returns: The currently configured alignment threshold + * + * Since: 1.14 + */ +GstClockTime +gst_audio_stream_align_get_alignment_threshold (GstAudioStreamAlign * align) +{ + g_return_val_if_fail (align != NULL, 0); + + return align->alignment_threshold; +} + +/** + * gst_audio_discont_set_discont_wait: + * @align: a #GstAudioStreamAlign + * @alignment_treshold: a new discont wait + * + * Sets @alignment_treshold as new discont wait for the following processing. + * + * Since: 1.14 + */ +void +gst_audio_stream_align_set_discont_wait (GstAudioStreamAlign * align, + GstClockTime discont_wait) +{ + g_return_if_fail (align != NULL); + + align->discont_wait = discont_wait; +} + +/** + * gst_audio_discont_get_discont_wait: + * @align: a #GstAudioStreamAlign + * + * Gets the currently configured discont wait. + * + * Returns: The currently configured discont wait + * + * Since: 1.14 + */ +GstClockTime +gst_audio_stream_align_get_discont_wait (GstAudioStreamAlign * align) +{ + g_return_val_if_fail (align != NULL, 0); + + return align->discont_wait; +} + +/** + * gst_audio_stream_align_mark_discont: + * @align: a #GstAudioStreamAlign + * + * Marks the next buffer as discontinuous and resets timestamp tracking. + * + * Since: 1.14 + */ +void +gst_audio_stream_align_mark_discont (GstAudioStreamAlign * align) +{ + g_return_if_fail (align != NULL); + + align->next_offset = -1; + align->discont_time = GST_CLOCK_TIME_NONE; +} + +/** + * gst_audio_stream_align_process: + * @align: a #GstAudioStreamAlign + * @discont: if this data is considered to be discontinuous + * @timestamp: a #GstClockTime of the start of the data + * @n_samples: number of samples to process + * @out_timestamp: (out): output timestamp of the data + * @out_duration: (out): output duration of the data + * @out_sample_position: (out): output sample position of the start of the data + * + * Processes data with @timestamp and @n_samples, and returns the output + * timestamp, duration and sample position together with a boolean to signal + * whether a discontinuity was detected or not. All non-discontinuous data + * will have perfect timestamps and durations. + * + * A discontinuity is detected once the difference between the actual + * timestamp and the timestamp calculated from the sample count since the last + * discontinuity differs by more than the alignment threshold for a duration + * longer than discont wait. + * + * Returns: %TRUE if a discontinuity was detected, %FALSE otherwise. + * + * Since: 1.14 + */ +gboolean +gst_audio_stream_align_process (GstAudioStreamAlign * align, + gboolean discont, GstClockTime timestamp, guint n_samples, + GstClockTime * out_timestamp, GstClockTime * out_duration, + guint64 * out_sample_position) +{ + GstClockTime start_time, end_time, duration; + guint64 start_offset, end_offset; + + g_return_val_if_fail (align != NULL, FALSE); + + start_time = timestamp; + start_offset = gst_util_uint64_scale (start_time, align->rate, GST_SECOND); + + end_offset = start_offset + n_samples; + end_time = gst_util_uint64_scale_int (end_offset, GST_SECOND, align->rate); + + duration = end_time - start_time; + + if (align->next_offset == (guint64) - 1 || discont) { + discont = TRUE; + } else { + guint64 diff, max_sample_diff; + + /* Check discont */ + if (start_offset <= align->next_offset) + diff = align->next_offset - start_offset; + else + diff = start_offset - align->next_offset; + + max_sample_diff = + gst_util_uint64_scale_int (align->alignment_threshold, + align->rate, GST_SECOND); + + /* Discont! */ + if (G_UNLIKELY (diff >= max_sample_diff)) { + if (align->discont_wait > 0) { + if (align->discont_time == GST_CLOCK_TIME_NONE) { + align->discont_time = start_time; + } else if ((start_time >= align->discont_time + && start_time - align->discont_time >= align->discont_wait) + || (start_time < align->discont_time + && align->discont_time - start_time >= align->discont_wait)) { + discont = TRUE; + align->discont_time = GST_CLOCK_TIME_NONE; + } + } else { + discont = TRUE; + } + } else if (G_UNLIKELY (align->discont_time != GST_CLOCK_TIME_NONE)) { + /* we have had a discont, but are now back on track! */ + align->discont_time = GST_CLOCK_TIME_NONE; + } + } + + if (discont) { + /* Have discont, need resync and use the capture timestamps */ + if (align->next_offset != (guint64) - 1) + GST_INFO ("Have discont. Expected %" + G_GUINT64_FORMAT ", got %" G_GUINT64_FORMAT, + align->next_offset, start_offset); + align->next_offset = end_offset; + + /* Got a discont and adjusted, reset the discont_time marker */ + align->discont_time = GST_CLOCK_TIME_NONE; + } else { + + /* No discont, just keep counting */ + timestamp = + gst_util_uint64_scale (align->next_offset, GST_SECOND, align->rate); + + start_offset = align->next_offset; + align->next_offset += n_samples; + + duration = + gst_util_uint64_scale (align->next_offset, GST_SECOND, + align->rate) - timestamp; + } + + if (out_timestamp) + *out_timestamp = timestamp; + if (out_duration) + *out_duration = duration; + if (out_sample_position) + *out_sample_position = start_offset; + + return discont; +} diff --git a/gst-libs/gst/audio/gstaudiostreamalign.h b/gst-libs/gst/audio/gstaudiostreamalign.h new file mode 100644 index 0000000..541c06d --- /dev/null +++ b/gst-libs/gst/audio/gstaudiostreamalign.h @@ -0,0 +1,74 @@ +/* GStreamer + * Copyright (C) 2017 Sebastian Dröge + * + * gstaudiostreamalign.h: + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the + * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, + * Boston, MA 02110-1301, USA. + */ + +#ifndef __GST_AUDIO_STREAM_ALIGN_H__ +#define __GST_AUDIO_STREAM_ALIGN_H__ + +#include + +#define GST_TYPE_AUDIO_INFO_STREAM_ALIGN (gst_audio_stream_align_get_type ()) + +typedef struct _GstAudioStreamAlign GstAudioStreamAlign; + +GST_EXPORT +GType gst_audio_stream_align_get_type (void); + +GST_EXPORT +GstAudioStreamAlign * gst_audio_stream_align_new (gint rate, + GstClockTime alignment_threshold, + GstClockTime discont_wait); +GST_EXPORT +GstAudioStreamAlign * gst_audio_stream_align_copy (const GstAudioStreamAlign * align); +GST_EXPORT +void gst_audio_stream_align_free (GstAudioStreamAlign * align); + +GST_EXPORT +void gst_audio_stream_align_set_rate (GstAudioStreamAlign * align, + gint rate); +GST_EXPORT +gint gst_audio_stream_align_get_rate (GstAudioStreamAlign * align); + +GST_EXPORT +void gst_audio_stream_align_set_alignment_threshold (GstAudioStreamAlign * align, + GstClockTime alignment_threshold); +GST_EXPORT +GstClockTime gst_audio_stream_align_get_alignment_threshold (GstAudioStreamAlign * align); + +GST_EXPORT +void gst_audio_stream_align_set_discont_wait (GstAudioStreamAlign * align, + GstClockTime discont_wait); +GST_EXPORT +GstClockTime gst_audio_stream_align_get_discont_wait (GstAudioStreamAlign * align); + + +GST_EXPORT +void gst_audio_stream_align_mark_discont (GstAudioStreamAlign * align); + +GST_EXPORT +gboolean gst_audio_stream_align_process (GstAudioStreamAlign * align, + gboolean discont, + GstClockTime timestamp, + guint n_samples, + GstClockTime *out_timestamp, + GstClockTime *out_duration, + guint64 *out_sample_position); + +#endif /* __GST_AUDIO_STREAM_ALIGN_H__ */ diff --git a/gst-libs/gst/audio/meson.build b/gst-libs/gst/audio/meson.build index f225294..1f14a27 100644 --- a/gst-libs/gst/audio/meson.build +++ b/gst-libs/gst/audio/meson.build @@ -21,6 +21,7 @@ audio_src= [ 'gstaudiosrc.c', 'gstaudioutilsprivate.c', 'streamvolume.c', + 'gstaudiostreamalign.c', ] audio_mkenum_headers = [ @@ -36,6 +37,7 @@ audio_mkenum_headers = [ 'gstaudiobasesrc.h', 'gstaudiocdsrc.h', 'gstaudiobasesink.h', + 'gstaudiostreamalign.h', ] # FIXME: check headers diff --git a/tests/check/libs/audio.c b/tests/check/libs/audio.c index 3cbc9e9..996b888 100644 --- a/tests/check/libs/audio.c +++ b/tests/check/libs/audio.c @@ -705,6 +705,184 @@ GST_START_TEST (test_fill_silence) GST_END_TEST; +GST_START_TEST (test_stream_align) +{ + GstAudioStreamAlign *align; + guint i; + GstClockTime timestamp; + GstClockTime out_timestamp, out_duration; + gboolean discont; + + align = gst_audio_stream_align_new (1000); + + for (i = 0; i < 500; i++) { + timestamp = 10 * GST_MSECOND * i; + discont = i == 0; + + discont = + gst_audio_stream_align_process (align, discont, timestamp, 10, + &out_timestamp, &out_duration, NULL); + + fail_unless_equals_uint64 (out_timestamp, 10 * GST_MSECOND * i); + fail_unless_equals_uint64 (out_duration, 10 * GST_MSECOND); + if (i == 0) + fail_unless (discont); + else + fail_unless (!discont); + } + + /* Drift forwards by 1ms per 10ms buffer for the first 40 buffers. + * - after 40 buffers we're above alignment threshold + * - after 40 + 100 buffers we're at discont wait + */ + for (i = 0; i < 500; i++) { + timestamp = 10 * GST_MSECOND * i; + discont = i == 0; + if (i > 0) + timestamp += 1 * GST_MSECOND * MIN (i, 40); + + discont = + gst_audio_stream_align_process (align, discont, timestamp, 10, + &out_timestamp, &out_duration, NULL); + + if (i < 140) { + fail_unless_equals_uint64 (out_timestamp, 10 * GST_MSECOND * i); + fail_unless_equals_uint64 (out_duration, 10 * GST_MSECOND); + if (i == 0) + fail_unless (discont); + else + fail_unless (!discont); + } else { + if (i == 140) + fail_unless (discont); + else + fail_unless (!discont); + fail_unless_equals_uint64 (out_timestamp, + 10 * GST_MSECOND * i + 40 * GST_MSECOND); + fail_unless_equals_uint64 (out_duration, 10 * GST_MSECOND); + } + } + + /* Drift backwards by 1ms per 10ms buffer for the first 40 buffers. + * - after 40 buffers we're above alignment threshold + * - after 40 + 100 buffers we're at discont wait + */ + for (i = 0; i < 500; i++) { + timestamp = 10 * GST_MSECOND * i; + discont = i == 0; + if (i > 0) + timestamp -= 1 * GST_MSECOND * MIN (i, 40); + + discont = + gst_audio_stream_align_process (align, discont, timestamp, 10, + &out_timestamp, &out_duration, NULL); + + if (i < 140) { + fail_unless_equals_uint64 (out_timestamp, 10 * GST_MSECOND * i); + fail_unless_equals_uint64 (out_duration, 10 * GST_MSECOND); + if (i == 0) + fail_unless (discont); + else + fail_unless (!discont); + } else { + if (i == 140) + fail_unless (discont); + else + fail_unless (!discont); + + fail_unless_equals_uint64 (out_timestamp, + 10 * GST_MSECOND * i - 40 * GST_MSECOND); + fail_unless_equals_uint64 (out_duration, 10 * GST_MSECOND); + } + } + + /* Shift all buffers but the first by 40ms + * - after 1 buffers we're above alignment threshold + * - after 101 buffers we're at discont wait + */ + for (i = 0; i < 500; i++) { + timestamp = 10 * GST_MSECOND * i; + discont = i == 0; + if (i > 0) + timestamp += 40 * GST_MSECOND; + + discont = + gst_audio_stream_align_process (align, discont, timestamp, 10, + &out_timestamp, &out_duration, NULL); + + if (i < 101) { + fail_unless_equals_uint64 (out_timestamp, 10 * GST_MSECOND * i); + fail_unless_equals_uint64 (out_duration, 10 * GST_MSECOND); + if (i == 0) + fail_unless (discont); + else + fail_unless (!discont); + } else { + if (i == 101) + fail_unless (discont); + else + fail_unless (!discont); + fail_unless_equals_uint64 (out_timestamp, + 10 * GST_MSECOND * i + 40 * GST_MSECOND); + fail_unless_equals_uint64 (out_duration, 10 * GST_MSECOND); + } + } + + /* Shift every second buffer by 40ms: + * - never discont! + */ + for (i = 0; i < 500; i++) { + timestamp = 10 * GST_MSECOND * i; + discont = i == 0; + + if (i % 2 == 0 && i > 0) + timestamp += 40 * GST_MSECOND; + + discont = + gst_audio_stream_align_process (align, discont, timestamp, 10, + &out_timestamp, &out_duration, NULL); + + fail_unless_equals_uint64 (out_timestamp, 10 * GST_MSECOND * i); + fail_unless_equals_uint64 (out_duration, 10 * GST_MSECOND); + if (i == 0) + fail_unless (discont); + else + fail_unless (!discont); + } + + /* Shift every buffer 100 by 2: discont at buffer 200 + */ + for (i = 0; i < 500; i++) { + timestamp = 10 * GST_MSECOND * i; + discont = i == 0; + if (i >= 100) + timestamp += 2 * GST_SECOND; + + discont = + gst_audio_stream_align_process (align, discont, timestamp, 10, + &out_timestamp, &out_duration, NULL); + + if (i < 200) { + fail_unless_equals_uint64 (out_timestamp, 10 * GST_MSECOND * i); + fail_unless_equals_uint64 (out_duration, 10 * GST_MSECOND); + if (i == 0) + fail_unless (discont); + else + fail_unless (!discont); + } else { + fail_unless_equals_uint64 (out_timestamp, + 10 * GST_MSECOND * i + 2 * GST_SECOND); + fail_unless_equals_uint64 (out_duration, 10 * GST_MSECOND); + if (i == 200) + fail_unless (discont); + else + fail_unless (!discont); + } + } +} + +GST_END_TEST; + static Suite * audio_suite (void) { @@ -732,6 +910,7 @@ audio_suite (void) tcase_add_test (tc_chain, test_audio_format_s8); tcase_add_test (tc_chain, test_audio_format_u8); tcase_add_test (tc_chain, test_fill_silence); + tcase_add_test (tc_chain, test_stream_align); return s; } diff --git a/win32/common/libgstaudio.def b/win32/common/libgstaudio.def index 26e3038..9a47e43 100644 --- a/win32/common/libgstaudio.def +++ b/win32/common/libgstaudio.def @@ -209,6 +209,18 @@ EXPORTS gst_audio_ring_buffer_stop gst_audio_sink_get_type gst_audio_src_get_type + gst_audio_stream_align_copy + gst_audio_stream_align_free + gst_audio_stream_align_get_alignment_threshold + gst_audio_stream_align_get_discont_wait + gst_audio_stream_align_get_rate + gst_audio_stream_align_get_type + gst_audio_stream_align_mark_discont + gst_audio_stream_align_new + gst_audio_stream_align_process + gst_audio_stream_align_set_alignment_threshold + gst_audio_stream_align_set_discont_wait + gst_audio_stream_align_set_rate gst_buffer_add_audio_clipping_meta gst_buffer_add_audio_downmix_meta gst_buffer_get_audio_downmix_meta_for_channels