Add stream helper utilities and IVF frame iterator (#1082)

* Add stream helper utilities and IVF frame iterator

* fix lint

* some cosmetics

* fix lint

* changes

* improve test

* improve types and test

* add todo for better bitrate calculation

tests/test_stream_helper.py

@@ -0,0 +1,69 @@
+import os
+import subprocess
+
+from facefusion import ffmpeg_builder
+from facefusion.apis.stream_helper import calculate_bitrate, calculate_buffer_size, forward_stream_frame, get_websocket_stream_mode, read_pipe_buffer
+from facefusion.vision import pack_resolution
+
+
+def make_scope(protocol : str) -> dict[str, object]:
+	return\
+	{
+		'type': 'websocket',
+		'headers': [ (b'sec-websocket-protocol', protocol.encode()) ]
+	}
+
+
+def test_calculate_bitrate() -> None:
+	assert calculate_bitrate((320, 240)) == 674
+	assert calculate_bitrate((640, 480)) == 1347
+	assert calculate_bitrate((1280, 720)) == 2333
+	assert calculate_bitrate((1920, 1080)) == 3500
+	assert calculate_bitrate((3840, 2160)) == 7000
+
+
+def test_calculate_buffer_size() -> None:
+	assert calculate_buffer_size((320, 240)) == 1348
+	assert calculate_buffer_size((640, 480)) == 2694
+	assert calculate_buffer_size((1280, 720)) == 4666
+	assert calculate_buffer_size((1920, 1080)) == 7000
+	assert calculate_buffer_size((3840, 2160)) == 14000
+
+
+def test_get_websocket_stream_mode() -> None:
+	assert get_websocket_stream_mode(make_scope('image')) == 'image'
+	assert get_websocket_stream_mode(make_scope('video')) == 'video'
+
+
+def test_read_pipe_buffer() -> None:
+	read_fd, write_fd = os.pipe()
+	os.write(write_fd, b'abcdefgh')
+	os.close(write_fd)
+
+	assert read_pipe_buffer(read_fd, 4) == b'abcd'
+	assert read_pipe_buffer(read_fd, 4) == b'efgh'
+	assert read_pipe_buffer(read_fd, 1) is None
+
+	os.close(read_fd)
+
+
+def test_forward_frames() -> None:
+	resolution = (320, 240)
+	frame_size = resolution[0] * resolution[1] * 3
+	commands = ffmpeg_builder.run(ffmpeg_builder.chain(
+		ffmpeg_builder.capture_video(),
+		ffmpeg_builder.set_media_resolution(pack_resolution(resolution)),
+		ffmpeg_builder.set_input_fps(30),
+		ffmpeg_builder.set_input('-'),
+		ffmpeg_builder.set_video_encoder('libvpx'),
+		ffmpeg_builder.set_encoder_deadline('realtime'),
+		ffmpeg_builder.set_stream_quality(400),
+		ffmpeg_builder.set_muxer('ivf'),
+		ffmpeg_builder.set_output('-')
+	))
+	encoder = subprocess.Popen(commands, stdin = subprocess.PIPE, stdout = subprocess.PIPE, stderr = subprocess.PIPE)
+	encoder.stdin.write(bytes(frame_size))
+	encoder.stdin.close()
+
+	for stream_buffer in forward_stream_frame(encoder):
+		assert 0 < len(stream_buffer) < frame_size