video-streaming-poc/common.py

from abc import ABC, abstractmethod

import numpy as np
from uuid import UUID

# The basic structure of the packet is as follows:
#  FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF ... FFFF
# | uuid              |    |    |                                           |
# |                   |    |    | image data: contains the 16x16 image slice bitpacked from a NumPy array
# |                   |    | y: the y position of this packet in the original image
# |                   | x: the x position of this packet in the original image
# | uuid: matches the packet to the requesting client
# Other packet types may change this structure. Need to standardize this somehow.

class Packet(ABC):
    """Generic structure for a video streaming packet. Contains a slice of the full image, which will be reconstructed
    by the server."""
    size: int
    def __init__(self, uuid: UUID, x: int, y: int, array: np.ndarray):
        self.uuid = uuid
        self.x = x
        self.y = y
        self.array = array

    @abstractmethod
    def to_bytestr(self) -> bytes:
        """Convert a packet object into a bytestring."""
        pass

    @abstractmethod
    def apply(self, image: np.ndarray) -> np.ndarray:
        """Apply this packet to an image."""
        pass

class StdPacket(Packet):
    """A standard packet with no interlacing. Sends a 16x16 chunk of an image."""
    size = 16 + 4 + 4 + 768
    def __init__(self, uuid: UUID, x: int, y: int, array: np.ndarray):
        super().__init__(uuid, x, y, array)
        
    def to_bytestr(self) -> bytes:
        bytestr = b""
        bytestr += self.uuid.bytes
        bytestr += self.x.to_bytes(length=4, signed = False)
        bytestr += self.y.to_bytes(length=4, signed = False)
        bytestr += self.array.tobytes()
        return bytestr

    def apply(self, image: np.ndarray) -> np.ndarray:
        x = self.x
        y = self.y
        arr = self.array
        image[y:y + 16, x:x + 16] = arr
        return image

def from_bytes_std(b: bytes) -> StdPacket:
    """Convert a byte string obtained via UDP into a packet object."""
    uuid = UUID(bytes = b[0:16])
    x = int.from_bytes(b[16:20], signed = False)
    y = int.from_bytes(b[20:24], signed = False)
    array = np.frombuffer(b[24:], np.uint8).reshape(16, 16, 3)

    return StdPacket(uuid, x, y, array)


class InterlacedPacket(Packet):
    """A packet with horizontal interlacing. Sends half of a 16x32 chunk of an image, every other row"""
    size = 16 + 4 + 4 + 4 + 768
    def __init__(self, uuid: UUID, x: int, y: int, even: bool, array: np.ndarray):
        super().__init__(uuid, x, y, array)
        self.even = even

    def to_bytestr(self) -> bytes:
        bytestr = b""
        bytestr += self.uuid.bytes
        bytestr += self.x.to_bytes(length=4, signed=False)
        bytestr += self.y.to_bytes(length=4, signed=False)
        bytestr += self.even.to_bytes(length=4)
        bytestr += self.array.tobytes()
        return bytestr

    def apply(self, image: np.ndarray) -> np.ndarray:
        x = self.x
        y = self.y
        arr = self.array
        image[y + self.even:y + 32:2, x:x + 16] = arr
        return image


def from_bytes_int(b: bytes) -> InterlacedPacket:
    """Convert a byte string obtained via UDP into a packet object."""
    uuid = UUID(bytes=b[0:16])
    x = int.from_bytes(b[16:20], signed=False)
    y = int.from_bytes(b[20:24], signed=False)
    even = bool.from_bytes(b[24:28])
    array = np.frombuffer(b[28:], np.uint8).reshape(16, 16, 3)

    return InterlacedPacket(uuid, x, y, even, array)

class DoublyInterlacedPacket(Packet):
    """A packet with horizontal interlacing. Sends one quarter of a 32x32 chunk of an image. This will alternate rows
    and columns based on the value of even_x and even_y."""
    size = 16 + 4 + 4 + 4 + 768
    def __init__(self, uuid: UUID, x: int, y: int, even_x: bool, even_y: bool, array: np.ndarray):
        super().__init__(uuid, x, y, array)
        self.even_x = even_x
        self.even_y = even_y

    def to_bytestr(self) -> bytes:
        bytestr = b""
        bytestr += self.uuid.bytes
        bytestr += self.x.to_bytes(length=4, signed=False)
        bytestr += self.y.to_bytes(length=4, signed=False)
        bytestr += self.even_x.to_bytes(length=2)
        bytestr += self.even_y.to_bytes(length=2)
        bytestr += self.array.tobytes()
        return bytestr

    def apply(self, image: np.ndarray) -> np.ndarray:
        x = self.x
        y = self.y
        arr = self.array
        image[y + self.even_y:y + 32:2, x + self.even_x:x + 32:2] = arr
        return image


def from_bytes_dint(b: bytes) -> DoublyInterlacedPacket:
    """Convert a byte string obtained via UDP into a packet object."""
    uuid = UUID(bytes=b[0:16])
    x = int.from_bytes(b[16:20], signed=False)
    y = int.from_bytes(b[20:24], signed=False)
    even_x = bool.from_bytes(b[24:26])
    even_y = bool.from_bytes(b[26:28])
    array = np.frombuffer(b[28:], np.uint8).reshape(16, 16, 3)

    return DoublyInterlacedPacket(uuid, x, y, even_x, even_y, array)

class TiledImagePacket(Packet):
    """Distributed selection from image."""
    size = 16 + 4 + 4 + 768

    def __init__(self, uuid: UUID, x: int, y: int, width: int, height: int, array: np.ndarray):
        super().__init__(uuid, x, y, array)
        self.width = width
        self.height = height
        self.xslice = width // 16
        self.yslice = height // 16

    def to_bytestr(self) -> bytes:
        bytestr = b""
        bytestr += self.uuid.bytes
        bytestr += self.x.to_bytes(length=4, signed=False)
        bytestr += self.y.to_bytes(length=4, signed=False)
        bytestr += self.array.tobytes()
        return bytestr

    def apply(self, image: np.ndarray) -> np.ndarray:
        x = self.x
        y = self.y
        arr = self.array
        image[y:self.height:self.yslice, x:self.width:self.xslice] = arr
        return image

def from_bytes_tiled(b: bytes) -> TiledImagePacket:
    """Convert a byte string obtained via UDP into a packet object."""
    uuid = UUID(bytes = b[0:16])
    x = int.from_bytes(b[16:20], signed = False)
    y = int.from_bytes(b[20:24], signed = False)
    array = np.frombuffer(b[24:], np.uint8).reshape(16, 16, 3)

    return TiledImagePacket(uuid, x, y, 640, 480, array)