gstreamer/subprojects/gst-python/examples/plugins/python/mixer.py
Thibault Saunier fab64c0b3a python: Add a Gst.init_python function to be called from plugins
Plugins know that they will be initialized after Gst was initialized
so they can call the initialization function dedicated for the python
bindings

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2675>
2022-07-08 14:37:14 +00:00

104 lines
3 KiB
Python

'''
Simple mixer element, accepts 320 x 240 RGBA at 30 fps
on any number of sinkpads.
Requires PIL (Python Imaging Library)
Example pipeline:
gst-launch-1.0 py_videomixer name=mixer ! videoconvert ! autovideosink \
videotestsrc ! mixer. \
videotestsrc pattern=ball ! mixer. \
videotestsrc pattern=snow ! mixer.
'''
import gi
gi.require_version('Gst', '1.0')
gi.require_version('GstBase', '1.0')
gi.require_version('GObject', '2.0')
from gi.repository import Gst, GObject, GstBase
Gst.init_python()
try:
from PIL import Image
except ImportError:
Gst.error('py_videomixer requires PIL')
raise
# Completely fixed input / output
ICAPS = Gst.Caps(Gst.Structure('video/x-raw',
format='RGBA',
width=320,
height=240,
framerate=Gst.Fraction(30, 1)))
OCAPS = Gst.Caps(Gst.Structure('video/x-raw',
format='RGBA',
width=320,
height=240,
framerate=Gst.Fraction(30, 1)))
class BlendData:
def __init__(self, outimg):
self.outimg = outimg
self.pts = 0
self.eos = True
class Videomixer(GstBase.Aggregator):
__gstmetadata__ = ('Videomixer','Video/Mixer', \
'Python video mixer', 'Mathieu Duponchelle')
__gsttemplates__ = (
Gst.PadTemplate.new_with_gtype("sink_%u",
Gst.PadDirection.SINK,
Gst.PadPresence.REQUEST,
ICAPS,
GstBase.AggregatorPad.__gtype__),
Gst.PadTemplate.new_with_gtype("src",
Gst.PadDirection.SRC,
Gst.PadPresence.ALWAYS,
OCAPS,
GstBase.AggregatorPad.__gtype__)
)
def mix_buffers(self, agg, pad, bdata):
buf = pad.pop_buffer()
_, info = buf.map(Gst.MapFlags.READ)
img = Image.frombuffer('RGBA', (320, 240), info.data, "raw", 'RGBA', 0, 1)
bdata.outimg = Image.blend(bdata.outimg, img, alpha=0.5)
bdata.pts = buf.pts
buf.unmap(info)
bdata.eos = False
return True
def do_aggregate(self, timeout):
outimg = Image.new('RGBA', (320, 240), 0x00000000)
bdata = BlendData(outimg)
self.foreach_sink_pad(self.mix_buffers, bdata)
data = bdata.outimg.tobytes()
outbuf = Gst.Buffer.new_allocate(None, len(data), None)
outbuf.fill(0, data)
outbuf.pts = bdata.pts
self.finish_buffer (outbuf)
# We are EOS when no pad was ready to be aggregated,
# this would obviously not work for live
if bdata.eos:
return Gst.FlowReturn.EOS
return Gst.FlowReturn.OK
GObject.type_register(Videomixer)
__gstelementfactory__ = ("py_videomixer", Gst.Rank.NONE, Videomixer)