Commit ec1e20ff authored by Sebastian Dröge's avatar Sebastian Dröge
Browse files

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
parent 0e8a510e
......@@ -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
<SUBSECTION Standard>
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
<SUBSECTION Private>
_GST_AUDIO_FORMAT_NE
</SECTION>
......
......@@ -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
......
......@@ -31,6 +31,7 @@
#include <gst/audio/audio-quantize.h>
#include <gst/audio/audio-converter.h>
#include <gst/audio/audio-resampler.h>
#include <gst/audio/gstaudiostreamalign.h>
G_BEGIN_DECLS
......
/* GStreamer
* Copyright (C) 2017 Sebastian Dröge <sebastian@centricular.com>
*
* 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;
}
/* GStreamer
* Copyright (C) 2017 Sebastian Dröge <sebastian@centricular.com>
*
* 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 <gst/gst.h>
#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__ */
......@@ -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
......
......@@ -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);