def _create_main_pipeline(self, device, size, fps, sync):
self.pipeline = Gst.Pipeline()
self.source = Gst.ElementFactory.make('v4l2src', 'source')
self.source.set_property('device', device)
self.source.set_property('do-timestamp', 'true')
# run 'v4l2-ctl --list-ctrls' for full list of controls
struct, _ = Gst.structure_from_string('name,\
white_balance_temperature_auto=(bool){0},\
backlight_compensation=(int){0},\
exposure_auto=0,\
focus_auto=(bool){0}')
self.source.set_property('extra-controls', struct)
caps = Gst.caps_from_string(
'video/x-raw,format=(string){BGR},width=%d,height=%d,framerate=%d/1'
% (size[1], size[0], fps))
self.sink = Gst.ElementFactory.make('appsink', 'sink')
self.sink.set_property('emit-signals', True)
self.sink.set_property('sync', sync)
self.sink.set_property('drop', True)
self.sink.set_property('max-buffers', 1)
self.sink.set_property('caps', caps)
self.sink.emit('pull-preroll')
self.pipeline.add(self.source)
self.pipeline.add(self.sink)
Gst.Element.link(self.source, self.sink)
def buffer_probe(pad, buffer, unused_user_data):
# this comes from another thread
caps = pad.query_caps(None).to_string()
kaps = Gst.structure_from_string(caps)
in_rate = 44100 # kaps[0].get_value('rate')
# now do necessary filtercaps
self.rate = in_rate
if self.bitrate > -1:
maxsamplerate = get_max_sample_rate(self.bitrate, self.channels)
if in_rate > maxsamplerate:
self.rate = get_preferred_sample_rate(maxsamplerate)
self.debug(
"rate %d > max rate %d (for %d kbit/sec), "
"selecting rate %d instead" % (in_rate, maxsamplerate, self.bitrate, self.rate)
)
caps_str = "audio/x-raw, rate=%d, channels=%d" % (self.rate, self.channels)
cf.set_property("caps", Gst.caps_from_string(caps_str))
pad.remove_probe(handle)
return True
def get_pipeline_string(self, properties):
capsString = properties.get('format', 'video/x-raw')
if capsString == 'video/x-raw':
capsString = '%s,format=(string)I420' % capsString
# Filtered caps
struct = Gst.structure_from_string(capsString)[0]
for k in 'width', 'height':
if k in properties:
struct.set_value(k, properties[k])
if 'framerate' in properties:
framerate = properties['framerate']
struct.set_value('framerate', Gst.Fraction(framerate[0]/framerate[1]))
# always set par
struct.set_value('pixel-aspect-ratio', Gst.Fraction(1/1))
if 'pixel-aspect-ratio' in properties:
par = properties['pixel-aspect-ratio']
struct.set_value('pixel-aspect-ratio', Gst.Fraction(par[0]/par[1]))
# If RGB, set something ffmpegcolorspace can convert.
if capsString == 'video/x-raw-rgb':
struct.set_value('red_mask', 0xff00)
caps = Gst.Caps.from_string(struct.to_string())
is_live = 'is-live=true'
overlay = ""
overlayTimestamps = properties.get('overlay-timestamps', False)
if overlayTimestamps:
overlay = " timeoverlay ! "
return "videotestsrc %s name=source ! " % is_live + overlay + \
"identity name=identity silent=TRUE ! %s" % caps
