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1# This Source Code Form is subject to the terms of the Mozilla Public
2# License, v. 2.0. If a copy of the MPL was not distributed with this
3# file, You can obtain one at https://mozilla.org/MPL/2.0/.
4#
5# This file incorporates work covered by the following copyright and
6# permission notice:
7#
8# Copyright (c) Jeremy Lainé.
9# All rights reserved.
10#
11# Redistribution and use in source and binary forms, with or without
12# modification, are permitted provided that the following conditions are met:
13#
14# * Redistributions of source code must retain the above copyright notice,
15# this list of conditions and the following disclaimer.
16# * Redistributions in binary form must reproduce the above copyright notice,
17# this list of conditions and the following disclaimer in the documentation
18# and/or other materials provided with the distribution.
19# * Neither the name of aiortc nor the names of its contributors may
20# be used to endorse or promote products derived from this software without
21# specific prior written permission.
22#
23# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
24# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
25# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
26# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
27# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
29# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
30# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
32# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34import fractions
35import uuid
36from abc import ABCMeta, abstractmethod
37from typing import Any
39from pyee.asyncio import AsyncIOEventEmitter
41VIDEO_CLOCK_RATE = 90000
42VIDEO_TIME_BASE = fractions.Fraction(1, VIDEO_CLOCK_RATE)
45def convert_timebase(
46 pts: int, from_base: fractions.Fraction, to_base: fractions.Fraction
47) -> int:
48 if from_base != to_base:
49 pts = int(pts * from_base / to_base)
50 return pts
53class MediaStreamError(Exception):
54 pass
57class MediaStreamTrack(AsyncIOEventEmitter, metaclass=ABCMeta):
58 """
59 A single media track within a stream.
60 """
62 kind = "unknown"
64 def __init__(self) -> None:
65 super().__init__()
66 self.__ended = False
67 self._id = str(uuid.uuid4())
69 @property
70 def id(self) -> str:
71 """
72 An automatically generated globally unique ID.
73 """
74 return self._id
76 @property
77 def readyState(self) -> str:
78 return "ended" if self.__ended else "live"
80 @abstractmethod
81 async def recv(self) -> Any:
82 """Receive the next media sample. Selkies' tracks serve a pre-encoded
83 `EncodedPacket` from pixelflux/pcmflux."""
85 def stop(self) -> None:
86 if not self.__ended:
87 self.__ended = True
88 self.emit("ended")
90 # no more events will be emitted, so remove all event listeners
91 # to facilitate garbage collection.
92 self.remove_all_listeners()
95class AudioStreamTrack(MediaStreamTrack):
96 """Base audio track. Selkies' `AudioMedia` overrides `recv` to serve
97 pre-encoded packets from pcmflux; the base itself produces nothing."""
99 kind = "audio"
101 async def recv(self) -> Any:
102 raise NotImplementedError("recv() must be implemented by a subclass")
105class VideoStreamTrack(MediaStreamTrack):
106 """Base video track. Selkies' `VideoMedia` overrides `recv` to serve
107 pre-encoded packets from pixelflux; the base itself produces nothing."""
109 kind = "video"
111 async def recv(self) -> Any:
112 raise NotImplementedError("recv() must be implemented by a subclass")