gstreamer/sys/wasapi/gstwasapisrc.c

658 lines
20 KiB
C
Raw Normal View History

/*
* Copyright (C) 2008 Ole André Vadla Ravnås <ole.andre.ravnas@tandberg.com>
* Copyright (C) 2018 Centricular Ltd.
* Author: Nirbheek Chauhan <nirbheek@centricular.com>
*
* 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.
*/
/**
* SECTION:element-wasapisrc
* @title: wasapisrc
*
* Provides audio capture from the Windows Audio Session API available with
* Vista and newer.
*
* ## Example pipelines
* |[
* gst-launch-1.0 -v wasapisrc ! fakesink
* ]| Capture from the default audio device and render to fakesink.
*
* |[
* gst-launch-1.0 -v wasapisrc low-latency=true ! fakesink
* ]| Capture from the default audio device with the minimum possible latency and render to fakesink.
*
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "gstwasapisrc.h"
#include <avrt.h>
GST_DEBUG_CATEGORY_STATIC (gst_wasapi_src_debug);
#define GST_CAT_DEFAULT gst_wasapi_src_debug
static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS (GST_WASAPI_STATIC_CAPS));
#define DEFAULT_ROLE GST_WASAPI_DEVICE_ROLE_CONSOLE
#define DEFAULT_EXCLUSIVE FALSE
#define DEFAULT_LOW_LATENCY FALSE
#define DEFAULT_AUDIOCLIENT3 FALSE
enum
{
PROP_0,
PROP_ROLE,
PROP_DEVICE,
PROP_EXCLUSIVE,
PROP_LOW_LATENCY,
PROP_AUDIOCLIENT3
};
static void gst_wasapi_src_dispose (GObject * object);
static void gst_wasapi_src_finalize (GObject * object);
static void gst_wasapi_src_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_wasapi_src_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static GstCaps *gst_wasapi_src_get_caps (GstBaseSrc * bsrc, GstCaps * filter);
2013-03-28 15:52:26 +00:00
static gboolean gst_wasapi_src_open (GstAudioSrc * asrc);
static gboolean gst_wasapi_src_close (GstAudioSrc * asrc);
static gboolean gst_wasapi_src_prepare (GstAudioSrc * asrc,
GstAudioRingBufferSpec * spec);
2013-03-28 15:52:26 +00:00
static gboolean gst_wasapi_src_unprepare (GstAudioSrc * asrc);
static guint gst_wasapi_src_read (GstAudioSrc * asrc, gpointer data,
guint length, GstClockTime * timestamp);
2013-03-28 15:52:26 +00:00
static guint gst_wasapi_src_delay (GstAudioSrc * asrc);
static void gst_wasapi_src_reset (GstAudioSrc * asrc);
static GstClockTime gst_wasapi_src_get_time (GstClock * clock,
gpointer user_data);
#define gst_wasapi_src_parent_class parent_class
2013-03-28 15:52:26 +00:00
G_DEFINE_TYPE (GstWasapiSrc, gst_wasapi_src, GST_TYPE_AUDIO_SRC);
static void
gst_wasapi_src_class_init (GstWasapiSrcClass * klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);
GstBaseSrcClass *gstbasesrc_class = GST_BASE_SRC_CLASS (klass);
2013-03-28 15:52:26 +00:00
GstAudioSrcClass *gstaudiosrc_class = GST_AUDIO_SRC_CLASS (klass);
gobject_class->dispose = gst_wasapi_src_dispose;
gobject_class->finalize = gst_wasapi_src_finalize;
gobject_class->set_property = gst_wasapi_src_set_property;
gobject_class->get_property = gst_wasapi_src_get_property;
g_object_class_install_property (gobject_class,
PROP_ROLE,
g_param_spec_enum ("role", "Role",
"Role of the device: communications, multimedia, etc",
GST_WASAPI_DEVICE_TYPE_ROLE, DEFAULT_ROLE, G_PARAM_READWRITE |
G_PARAM_STATIC_STRINGS | GST_PARAM_MUTABLE_READY));
g_object_class_install_property (gobject_class,
PROP_DEVICE,
g_param_spec_string ("device", "Device",
"WASAPI playback device as a GUID string",
NULL, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class,
PROP_EXCLUSIVE,
g_param_spec_boolean ("exclusive", "Exclusive mode",
"Open the device in exclusive mode",
DEFAULT_EXCLUSIVE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class,
PROP_LOW_LATENCY,
g_param_spec_boolean ("low-latency", "Low latency",
"Optimize all settings for lowest latency. Always safe to enable.",
DEFAULT_LOW_LATENCY, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class,
PROP_AUDIOCLIENT3,
g_param_spec_boolean ("use-audioclient3", "Use the AudioClient3 API",
"Whether to use the Windows 10 AudioClient3 API when available",
DEFAULT_AUDIOCLIENT3, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
gst_element_class_add_static_pad_template (gstelement_class, &src_template);
gst_element_class_set_static_metadata (gstelement_class, "WasapiSrc",
"Source/Audio",
"Stream audio from an audio capture device through WASAPI",
"Nirbheek Chauhan <nirbheek@centricular.com>, "
"Ole André Vadla Ravnås <ole.andre.ravnas@tandberg.com>");
2013-03-28 15:52:26 +00:00
gstbasesrc_class->get_caps = GST_DEBUG_FUNCPTR (gst_wasapi_src_get_caps);
2013-03-28 15:52:26 +00:00
gstaudiosrc_class->open = GST_DEBUG_FUNCPTR (gst_wasapi_src_open);
gstaudiosrc_class->close = GST_DEBUG_FUNCPTR (gst_wasapi_src_close);
gstaudiosrc_class->read = GST_DEBUG_FUNCPTR (gst_wasapi_src_read);
gstaudiosrc_class->prepare = GST_DEBUG_FUNCPTR (gst_wasapi_src_prepare);
gstaudiosrc_class->unprepare = GST_DEBUG_FUNCPTR (gst_wasapi_src_unprepare);
2013-03-28 15:52:26 +00:00
gstaudiosrc_class->delay = GST_DEBUG_FUNCPTR (gst_wasapi_src_delay);
gstaudiosrc_class->reset = GST_DEBUG_FUNCPTR (gst_wasapi_src_reset);
GST_DEBUG_CATEGORY_INIT (gst_wasapi_src_debug, "wasapisrc",
0, "Windows audio session API source");
}
static void
gst_wasapi_src_init (GstWasapiSrc * self)
{
2013-03-28 15:52:26 +00:00
/* override with a custom clock */
if (GST_AUDIO_BASE_SRC (self)->clock)
gst_object_unref (GST_AUDIO_BASE_SRC (self)->clock);
2013-03-28 15:52:26 +00:00
GST_AUDIO_BASE_SRC (self)->clock = gst_audio_clock_new ("GstWasapiSrcClock",
gst_wasapi_src_get_time, gst_object_ref (self),
(GDestroyNotify) gst_object_unref);
self->role = DEFAULT_ROLE;
self->sharemode = AUDCLNT_SHAREMODE_SHARED;
self->low_latency = DEFAULT_LOW_LATENCY;
self->try_audioclient3 = DEFAULT_AUDIOCLIENT3;
2013-03-28 15:52:26 +00:00
self->event_handle = CreateEvent (NULL, FALSE, FALSE, NULL);
CoInitialize (NULL);
}
static void
gst_wasapi_src_dispose (GObject * object)
{
GstWasapiSrc *self = GST_WASAPI_SRC (object);
2013-03-28 15:52:26 +00:00
if (self->event_handle != NULL) {
CloseHandle (self->event_handle);
self->event_handle = NULL;
}
if (self->client_clock != NULL) {
IUnknown_Release (self->client_clock);
self->client_clock = NULL;
}
if (self->client != NULL) {
IUnknown_Release (self->client);
self->client = NULL;
}
if (self->capture_client != NULL) {
IUnknown_Release (self->capture_client);
self->capture_client = NULL;
}
G_OBJECT_CLASS (parent_class)->dispose (object);
}
static void
gst_wasapi_src_finalize (GObject * object)
{
GstWasapiSrc *self = GST_WASAPI_SRC (object);
g_clear_pointer (&self->mix_format, CoTaskMemFree);
CoUninitialize ();
g_clear_pointer (&self->cached_caps, gst_caps_unref);
g_clear_pointer (&self->positions, g_free);
g_clear_pointer (&self->device_strid, g_free);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_wasapi_src_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstWasapiSrc *self = GST_WASAPI_SRC (object);
switch (prop_id) {
case PROP_ROLE:
self->role = gst_wasapi_device_role_to_erole (g_value_get_enum (value));
break;
case PROP_DEVICE:
{
const gchar *device = g_value_get_string (value);
g_free (self->device_strid);
self->device_strid =
device ? g_utf8_to_utf16 (device, -1, NULL, NULL, NULL) : NULL;
break;
}
case PROP_EXCLUSIVE:
self->sharemode = g_value_get_boolean (value)
? AUDCLNT_SHAREMODE_EXCLUSIVE : AUDCLNT_SHAREMODE_SHARED;
break;
case PROP_LOW_LATENCY:
self->low_latency = g_value_get_boolean (value);
break;
case PROP_AUDIOCLIENT3:
self->try_audioclient3 = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_wasapi_src_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstWasapiSrc *self = GST_WASAPI_SRC (object);
switch (prop_id) {
case PROP_ROLE:
g_value_set_enum (value, gst_wasapi_erole_to_device_role (self->role));
break;
case PROP_DEVICE:
g_value_take_string (value, self->device_strid ?
g_utf16_to_utf8 (self->device_strid, -1, NULL, NULL, NULL) : NULL);
break;
case PROP_EXCLUSIVE:
g_value_set_boolean (value,
self->sharemode == AUDCLNT_SHAREMODE_EXCLUSIVE);
break;
case PROP_LOW_LATENCY:
g_value_set_boolean (value, self->low_latency);
break;
case PROP_AUDIOCLIENT3:
g_value_set_boolean (value, self->try_audioclient3);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static gboolean
gst_wasapi_src_can_audioclient3 (GstWasapiSrc * self)
{
if (self->sharemode == AUDCLNT_SHAREMODE_SHARED &&
self->try_audioclient3 && gst_wasapi_util_have_audioclient3 ())
return TRUE;
return FALSE;
}
2013-03-28 15:52:26 +00:00
static GstCaps *
gst_wasapi_src_get_caps (GstBaseSrc * bsrc, GstCaps * filter)
{
GstWasapiSrc *self = GST_WASAPI_SRC (bsrc);
WAVEFORMATEX *format = NULL;
GstCaps *caps = NULL;
GST_DEBUG_OBJECT (self, "entering get caps");
if (self->cached_caps) {
caps = gst_caps_ref (self->cached_caps);
} else {
GstCaps *template_caps;
gboolean ret;
template_caps = gst_pad_get_pad_template_caps (bsrc->srcpad);
if (!self->client)
gst_wasapi_src_open (GST_AUDIO_SRC (bsrc));
ret = gst_wasapi_util_get_device_format (GST_ELEMENT (self),
self->sharemode, self->device, self->client, &format);
if (!ret) {
GST_ELEMENT_ERROR (self, STREAM, FORMAT, (NULL),
("failed to detect format"));
goto out;
}
gst_wasapi_util_parse_waveformatex ((WAVEFORMATEXTENSIBLE *) format,
template_caps, &caps, &self->positions);
if (caps == NULL) {
GST_ELEMENT_ERROR (self, STREAM, FORMAT, (NULL), ("unknown format"));
goto out;
}
{
gchar *pos_str = gst_audio_channel_positions_to_string (self->positions,
format->nChannels);
GST_INFO_OBJECT (self, "positions are: %s", pos_str);
g_free (pos_str);
}
self->mix_format = format;
gst_caps_replace (&self->cached_caps, caps);
gst_caps_unref (template_caps);
}
if (filter) {
GstCaps *filtered =
gst_caps_intersect_full (filter, caps, GST_CAPS_INTERSECT_FIRST);
gst_caps_unref (caps);
caps = filtered;
}
GST_DEBUG_OBJECT (self, "returning caps %" GST_PTR_FORMAT, caps);
out:
return caps;
2013-03-28 15:52:26 +00:00
}
static gboolean
gst_wasapi_src_open (GstAudioSrc * asrc)
{
GstWasapiSrc *self = GST_WASAPI_SRC (asrc);
gboolean res = FALSE;
IAudioClient *client = NULL;
IMMDevice *device = NULL;
if (self->client)
return TRUE;
/* FIXME: Switching the default device does not switch the stream to it,
* even if the old device was unplugged. We need to handle this somehow.
* For example, perhaps we should automatically switch to the new device if
* the default device is changed and a device isn't explicitly selected. */
if (!gst_wasapi_util_get_device_client (GST_ELEMENT (self), TRUE,
self->role, self->device_strid, &device, &client)) {
if (!self->device_strid)
GST_ELEMENT_ERROR (self, RESOURCE, OPEN_READ, (NULL),
("Failed to get default device"));
else
GST_ELEMENT_ERROR (self, RESOURCE, OPEN_READ, (NULL),
("Failed to open device %S", self->device_strid));
2013-03-28 15:52:26 +00:00
goto beach;
}
2013-03-28 15:52:26 +00:00
self->client = client;
self->device = device;
2013-03-28 15:52:26 +00:00
res = TRUE;
2013-03-28 15:52:26 +00:00
beach:
2013-03-28 15:52:26 +00:00
return res;
}
2013-03-28 15:52:26 +00:00
static gboolean
gst_wasapi_src_close (GstAudioSrc * asrc)
{
GstWasapiSrc *self = GST_WASAPI_SRC (asrc);
if (self->device != NULL) {
IUnknown_Release (self->device);
self->device = NULL;
}
2013-03-28 15:52:26 +00:00
if (self->client != NULL) {
IUnknown_Release (self->client);
self->client = NULL;
}
2013-03-28 15:52:26 +00:00
return TRUE;
}
static gboolean
2013-03-28 15:52:26 +00:00
gst_wasapi_src_prepare (GstAudioSrc * asrc, GstAudioRingBufferSpec * spec)
{
2013-03-28 15:52:26 +00:00
GstWasapiSrc *self = GST_WASAPI_SRC (asrc);
gboolean res = FALSE;
REFERENCE_TIME latency_rt;
guint bpf, rate, devicep_frames, buffer_frames;
HRESULT hr;
if (gst_wasapi_src_can_audioclient3 (self)) {
if (!gst_wasapi_util_initialize_audioclient3 (GST_ELEMENT (self), spec,
(IAudioClient3 *) self->client, self->mix_format, self->low_latency,
&devicep_frames))
goto beach;
} else {
if (!gst_wasapi_util_initialize_audioclient (GST_ELEMENT (self), spec,
self->client, self->mix_format, self->sharemode, self->low_latency,
&devicep_frames))
goto beach;
}
bpf = GST_AUDIO_INFO_BPF (&spec->info);
rate = GST_AUDIO_INFO_RATE (&spec->info);
2013-03-28 15:52:26 +00:00
/* Total size in frames of the allocated buffer that we will read from */
hr = IAudioClient_GetBufferSize (self->client, &buffer_frames);
HR_FAILED_GOTO (hr, IAudioClient::GetBufferSize, beach);
GST_INFO_OBJECT (self, "buffer size is %i frames, device period is %i "
"frames, bpf is %i bytes, rate is %i Hz", buffer_frames,
devicep_frames, bpf, rate);
/* Actual latency-time/buffer-time will be different now */
spec->segsize = devicep_frames * bpf;
/* We need a minimum of 2 segments to ensure glitch-free playback */
spec->segtotal = MAX (self->buffer_frame_count * bpf / spec->segsize, 2);
GST_INFO_OBJECT (self, "segsize is %i, segtotal is %i", spec->segsize,
spec->segtotal);
/* Get WASAPI latency for logging */
2013-03-28 15:52:26 +00:00
hr = IAudioClient_GetStreamLatency (self->client, &latency_rt);
HR_FAILED_GOTO (hr, IAudioClient::GetStreamLatency, beach);
GST_INFO_OBJECT (self, "wasapi stream latency: %" G_GINT64_FORMAT " (%"
G_GINT64_FORMAT " ms)", latency_rt, latency_rt / 10000);
2013-03-28 15:52:26 +00:00
/* Set the event handler which will trigger reads */
2013-03-28 15:52:26 +00:00
hr = IAudioClient_SetEventHandle (self->client, self->event_handle);
HR_FAILED_GOTO (hr, IAudioClient::SetEventHandle, beach);
2013-03-28 15:52:26 +00:00
/* Get the clock and the clock freq */
2013-03-28 15:52:26 +00:00
if (!gst_wasapi_util_get_clock (GST_ELEMENT (self), self->client,
&self->client_clock))
goto beach;
hr = IAudioClock_GetFrequency (self->client_clock, &self->client_clock_freq);
HR_FAILED_GOTO (hr, IAudioClock::GetFrequency, beach);
/* Get capture source client and start it up */
2013-03-28 15:52:26 +00:00
if (!gst_wasapi_util_get_capture_client (GST_ELEMENT (self), self->client,
&self->capture_client)) {
goto beach;
}
2013-03-28 15:52:26 +00:00
hr = IAudioClient_Start (self->client);
HR_FAILED_GOTO (hr, IAudioClock::Start, beach);
gst_audio_ring_buffer_set_channel_positions (GST_AUDIO_BASE_SRC
(self)->ringbuffer, self->positions);
/* Increase the thread priority to reduce glitches */
self->thread_priority_handle = gst_wasapi_util_set_thread_characteristics ();
res = TRUE;
beach:
/* unprepare() is not called if prepare() fails, but we want it to be, so call
* it manually when needed */
if (!res)
gst_wasapi_src_unprepare (asrc);
return res;
}
static gboolean
2013-03-28 15:52:26 +00:00
gst_wasapi_src_unprepare (GstAudioSrc * asrc)
{
2013-03-28 15:52:26 +00:00
GstWasapiSrc *self = GST_WASAPI_SRC (asrc);
if (self->sharemode == AUDCLNT_SHAREMODE_EXCLUSIVE &&
!gst_wasapi_src_can_audioclient3 (self))
CoUninitialize ();
if (self->thread_priority_handle != NULL) {
gst_wasapi_util_revert_thread_characteristics
(self->thread_priority_handle);
self->thread_priority_handle = NULL;
}
if (self->client != NULL) {
IAudioClient_Stop (self->client);
}
if (self->capture_client != NULL) {
IUnknown_Release (self->capture_client);
self->capture_client = NULL;
}
if (self->client_clock != NULL) {
IUnknown_Release (self->client_clock);
self->client_clock = NULL;
}
self->client_clock_freq = 0;
return TRUE;
}
2013-03-28 15:52:26 +00:00
static guint
gst_wasapi_src_read (GstAudioSrc * asrc, gpointer data, guint length,
GstClockTime * timestamp)
{
2013-03-28 15:52:26 +00:00
GstWasapiSrc *self = GST_WASAPI_SRC (asrc);
HRESULT hr;
gint16 *from = NULL;
guint wanted = length;
DWORD flags;
while (wanted > 0) {
guint have_frames, n_frames, want_frames, read_len;
/* Wait for data to become available */
WaitForSingleObject (self->event_handle, INFINITE);
hr = IAudioCaptureClient_GetBuffer (self->capture_client,
(BYTE **) & from, &have_frames, &flags, NULL, NULL);
if (hr != S_OK) {
gchar *msg = gst_wasapi_util_hresult_to_string (hr);
if (hr == AUDCLNT_S_BUFFER_EMPTY)
GST_WARNING_OBJECT (self, "IAudioCaptureClient::GetBuffer failed: %s"
", retrying", msg);
else
GST_ERROR_OBJECT (self, "IAudioCaptureClient::GetBuffer failed: %s",
msg);
g_free (msg);
length = 0;
goto beach;
}
if (flags != 0)
GST_INFO_OBJECT (self, "buffer flags=%#08x", (guint) flags);
/* XXX: How do we handle AUDCLNT_BUFFERFLAGS_SILENT? We're supposed to write
* out silence when that flag is set? See:
* https://msdn.microsoft.com/en-us/library/windows/desktop/dd370800(v=vs.85).aspx */
if (flags & AUDCLNT_BUFFERFLAGS_DATA_DISCONTINUITY)
GST_WARNING_OBJECT (self, "WASAPI reported glitch in buffer");
want_frames = wanted / self->mix_format->nBlockAlign;
/* If GetBuffer is returning more frames than we can handle, all we can do is
* hope that this is temporary and that things will settle down later. */
if (G_UNLIKELY (have_frames > want_frames))
GST_WARNING_OBJECT (self, "captured too many frames: have %i, want %i",
have_frames, want_frames);
/* Only copy data that will fit into the allocated buffer of size @length */
n_frames = MIN (have_frames, want_frames);
read_len = n_frames * self->mix_format->nBlockAlign;
{
guint bpf = self->mix_format->nBlockAlign;
GST_DEBUG_OBJECT (self, "have: %i (%i bytes), can read: %i (%i bytes), "
"will read: %i (%i bytes)", have_frames, have_frames * bpf,
want_frames, wanted, n_frames, read_len);
}
memcpy (data, from, read_len);
wanted -= read_len;
/* Always release all captured buffers if we've captured any at all */
hr = IAudioCaptureClient_ReleaseBuffer (self->capture_client, have_frames);
HR_FAILED_AND (hr, IAudioClock::ReleaseBuffer, goto beach);
}
beach:
2013-03-28 15:52:26 +00:00
return length;
}
static guint
gst_wasapi_src_delay (GstAudioSrc * asrc)
{
GstWasapiSrc *self = GST_WASAPI_SRC (asrc);
guint delay = 0;
HRESULT hr;
hr = IAudioClient_GetCurrentPadding (self->client, &delay);
HR_FAILED_RET (hr, IAudioClock::GetCurrentPadding, 0);
return delay;
2013-03-28 15:52:26 +00:00
}
static void
gst_wasapi_src_reset (GstAudioSrc * asrc)
{
GstWasapiSrc *self = GST_WASAPI_SRC (asrc);
HRESULT hr;
if (!self->client)
return;
2013-03-28 15:52:26 +00:00
hr = IAudioClient_Stop (self->client);
HR_FAILED_RET (hr, IAudioClock::Stop,);
hr = IAudioClient_Reset (self->client);
HR_FAILED_RET (hr, IAudioClock::Reset,);
}
static GstClockTime
gst_wasapi_src_get_time (GstClock * clock, gpointer user_data)
{
GstWasapiSrc *self = GST_WASAPI_SRC (user_data);
HRESULT hr;
guint64 devpos;
GstClockTime result;
if (G_UNLIKELY (self->client_clock == NULL))
return GST_CLOCK_TIME_NONE;
hr = IAudioClock_GetPosition (self->client_clock, &devpos, NULL);
HR_FAILED_RET (hr, IAudioClock::GetPosition, GST_CLOCK_TIME_NONE);
result = gst_util_uint64_scale_int (devpos, GST_SECOND,
self->client_clock_freq);
/*
GST_DEBUG_OBJECT (self, "devpos = %" G_GUINT64_FORMAT
" frequency = %" G_GUINT64_FORMAT
" result = %" G_GUINT64_FORMAT " ms",
devpos, self->client_clock_freq, GST_TIME_AS_MSECONDS (result));
*/
return result;
}