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'''
Element that generates a sine audio wave with the specified frequency
Requires numpy
Example pipeline:
gst-launch-1.0 py_audiotestsrc ! autoaudiosink
'''
import gi
gi.require_version('Gst', '1.0')
gi.require_version('GstBase', '1.0')
gi.require_version('GstAudio', '1.0')
from gi.repository import Gst, GLib, GObject, GstBase, GstAudio
try:
import numpy as np
except ImportError:
Gst.error('py_audiotestsrc requires numpy')
raise
Gst.init_python()
OCAPS = Gst.Caps.from_string (
'audio/x-raw, format=F32LE, layout=interleaved, rate=44100, channels=2')
SAMPLESPERBUFFER = 1024
DEFAULT_FREQ = 440
DEFAULT_VOLUME = 0.8
DEFAULT_MUTE = False
DEFAULT_IS_LIVE = False
class AudioTestSrc(GstBase.BaseSrc):
__gstmetadata__ = ('CustomSrc','Src', \
'Custom test src element', 'Mathieu Duponchelle')
__gproperties__ = {
"freq": (int,
"Frequency",
"Frequency of test signal",
1,
GLib.MAXINT,
DEFAULT_FREQ,
GObject.ParamFlags.READWRITE
),
"volume": (float,
"Volume",
"Volume of test signal",
0.0,
1.0,
DEFAULT_VOLUME,
GObject.ParamFlags.READWRITE
),
"mute": (bool,
"Mute",
"Mute the test signal",
DEFAULT_MUTE,
GObject.ParamFlags.READWRITE
),
"is-live": (bool,
"Is live",
"Whether to act as a live source",
DEFAULT_IS_LIVE,
GObject.ParamFlags.READWRITE
),
}
__gsttemplates__ = Gst.PadTemplate.new("src",
Gst.PadDirection.SRC,
Gst.PadPresence.ALWAYS,
OCAPS)
def __init__(self):
GstBase.BaseSrc.__init__(self)
self.info = GstAudio.AudioInfo()
self.freq = DEFAULT_FREQ
self.volume = DEFAULT_VOLUME
self.mute = DEFAULT_MUTE
self.set_live(DEFAULT_IS_LIVE)
self.set_format(Gst.Format.TIME)
def do_set_caps(self, caps):
self.info = GstAudio.AudioInfo.new_from_caps(caps)
self.set_blocksize(self.info.bpf * SAMPLESPERBUFFER)
return True
def do_get_property(self, prop):
if prop.name == 'freq':
return self.freq
elif prop.name == 'volume':
return self.volume
elif prop.name == 'mute':
return self.mute
elif prop.name == 'is-live':
return self.is_live
else:
raise AttributeError('unknown property %s' % prop.name)
def do_set_property(self, prop, value):
if prop.name == 'freq':
self.freq = value
elif prop.name == 'volume':
self.volume = value
elif prop.name == 'mute':
self.mute = value
elif prop.name == 'is-live':
self.set_live(value)
else:
raise AttributeError('unknown property %s' % prop.name)
def do_start (self):
self.next_sample = 0
self.next_byte = 0
self.next_time = 0
self.accumulator = 0
self.generate_samples_per_buffer = SAMPLESPERBUFFER
return True
def do_gst_base_src_query(self, query):
if query.type == Gst.QueryType.LATENCY:
latency = Gst.util_uint64_scale_int(self.generate_samples_per_buffer,
Gst.SECOND, self.info.rate)
is_live = self.is_live
query.set_latency(is_live, latency, Gst.CLOCK_TIME_NONE)
res = True
else:
res = GstBase.BaseSrc.do_query(self, query)
return res
def do_get_times(self, buf):
end = 0
start = 0
if self.is_live:
ts = buf.pts
if ts != Gst.CLOCK_TIME_NONE:
duration = buf.duration
if duration != Gst.CLOCK_TIME_NONE:
end = ts + duration
start = ts
else:
start = Gst.CLOCK_TIME_NONE
end = Gst.CLOCK_TIME_NONE
return start, end
def do_fill(self, offset, length, buf):
if length == -1:
samples = SAMPLESPERBUFFER
else:
samples = int(length / self.info.bpf)
self.generate_samples_per_buffer = samples
bytes_ = samples * self.info.bpf
next_sample = self.next_sample + samples
next_byte = self.next_byte + bytes_
next_time = Gst.util_uint64_scale_int(next_sample, Gst.SECOND, self.info.rate)
try:
with buf.map(Gst.MapFlags.WRITE) as info:
array = np.ndarray(shape = self.info.channels * samples, dtype = np.float32, buffer = info.data)
if not self.mute:
r = np.repeat(np.arange(self.accumulator, self.accumulator + samples),
self.info.channels)
np.sin(2 * np.pi * r * self.freq / self.info.rate, out=array)
array *= self.volume
else:
array[:] = 0
except Exception as e:
Gst.error("Mapping error: %s" % e)
return (Gst.FlowReturn.ERROR, None)
buf.offset = self.next_sample
buf.offset_end = next_sample
buf.pts = self.next_time
buf.duration = next_time - self.next_time
self.next_time = next_time
self.next_sample = next_sample
self.next_byte = next_byte
self.accumulator += samples
self.accumulator %= self.info.rate / self.freq
return (Gst.FlowReturn.OK, buf)
__gstelementfactory__ = ("py_audiotestsrc", Gst.Rank.NONE, AudioTestSrc)
|
