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from typing import Dict, List, Optional, Union
from ..rtcrtpparameters import (
ParametersDict,
RTCRtcpFeedback,
RTCRtpCapabilities,
RTCRtpCodecCapability,
RTCRtpCodecParameters,
RTCRtpHeaderExtensionCapability,
RTCRtpHeaderExtensionParameters,
)
from .base import Decoder, Encoder
from .g711 import PcmaDecoder, PcmaEncoder, PcmuDecoder, PcmuEncoder
from .h264 import H264Decoder, H264Encoder, h264_depayload
from .opus import OpusDecoder, OpusEncoder
from .vpx import Vp8Decoder, Vp8Encoder, vp8_depayload
PCMU_CODEC = RTCRtpCodecParameters(
mimeType="audio/PCMU", clockRate=8000, channels=1, payloadType=0
)
PCMA_CODEC = RTCRtpCodecParameters(
mimeType="audio/PCMA", clockRate=8000, channels=1, payloadType=8
)
CODECS: Dict[str, List[RTCRtpCodecParameters]] = {
"audio": [
RTCRtpCodecParameters(
mimeType="audio/opus", clockRate=48000, channels=2, payloadType=96
),
PCMU_CODEC,
PCMA_CODEC,
],
"video": [],
}
# Note, the id space for these extensions is shared across media types when BUNDLE
# is negotiated. If you add a audio- or video-specific extension, make sure it has
# a unique id.
HEADER_EXTENSIONS: Dict[str, List[RTCRtpHeaderExtensionParameters]] = {
"audio": [
RTCRtpHeaderExtensionParameters(
id=1, uri="urn:ietf:params:rtp-hdrext:sdes:mid"
),
RTCRtpHeaderExtensionParameters(
id=2, uri="urn:ietf:params:rtp-hdrext:ssrc-audio-level"
),
],
"video": [
RTCRtpHeaderExtensionParameters(
id=1, uri="urn:ietf:params:rtp-hdrext:sdes:mid"
),
RTCRtpHeaderExtensionParameters(
id=3, uri="http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time"
),
],
}
def init_codecs() -> None:
dynamic_pt = 97
def add_video_codec(
mimeType: str, parameters: Optional[ParametersDict] = None
) -> None:
nonlocal dynamic_pt
clockRate = 90000
CODECS["video"] += [
RTCRtpCodecParameters(
mimeType=mimeType,
clockRate=clockRate,
payloadType=dynamic_pt,
rtcpFeedback=[
RTCRtcpFeedback(type="nack"),
RTCRtcpFeedback(type="nack", parameter="pli"),
RTCRtcpFeedback(type="goog-remb"),
],
parameters=parameters or {},
),
RTCRtpCodecParameters(
mimeType="video/rtx",
clockRate=clockRate,
payloadType=dynamic_pt + 1,
parameters={"apt": dynamic_pt},
),
]
dynamic_pt += 2
add_video_codec("video/VP8")
for profile_level_id in ("42001f", "42e01f"):
add_video_codec(
"video/H264",
{
"level-asymmetry-allowed": "1",
"packetization-mode": "1",
"profile-level-id": profile_level_id,
},
)
def depayload(codec: RTCRtpCodecParameters, payload: bytes) -> bytes:
if codec.name == "VP8":
return vp8_depayload(payload)
elif codec.name == "H264":
return h264_depayload(payload)
else:
return payload
def get_capabilities(kind: str) -> RTCRtpCapabilities:
if kind not in CODECS:
raise ValueError(f"cannot get capabilities for unknown media {kind}")
codecs = []
rtx_added = False
for params in CODECS[kind]:
if not is_rtx(params):
codecs.append(
RTCRtpCodecCapability(
mimeType=params.mimeType,
clockRate=params.clockRate,
channels=params.channels,
parameters=params.parameters,
)
)
elif not rtx_added:
# There will only be a single entry in codecs[] for retransmission
# via RTX, with sdpFmtpLine not present.
codecs.append(
RTCRtpCodecCapability(
mimeType=params.mimeType, clockRate=params.clockRate
)
)
rtx_added = True
headerExtensions = []
for extension in HEADER_EXTENSIONS[kind]:
headerExtensions.append(RTCRtpHeaderExtensionCapability(uri=extension.uri))
return RTCRtpCapabilities(codecs=codecs, headerExtensions=headerExtensions)
def get_decoder(codec: RTCRtpCodecParameters) -> Decoder:
mimeType = codec.mimeType.lower()
if mimeType == "audio/opus":
return OpusDecoder()
elif mimeType == "audio/pcma":
return PcmaDecoder()
elif mimeType == "audio/pcmu":
return PcmuDecoder()
elif mimeType == "video/h264":
return H264Decoder()
elif mimeType == "video/vp8":
return Vp8Decoder()
else:
raise ValueError(f"No decoder found for MIME type `{mimeType}`")
def get_encoder(codec: RTCRtpCodecParameters) -> Encoder:
mimeType = codec.mimeType.lower()
if mimeType == "audio/opus":
return OpusEncoder()
elif mimeType == "audio/pcma":
return PcmaEncoder()
elif mimeType == "audio/pcmu":
return PcmuEncoder()
elif mimeType == "video/h264":
return H264Encoder()
elif mimeType == "video/vp8":
return Vp8Encoder()
else:
raise ValueError(f"No encoder found for MIME type `{mimeType}`")
def is_rtx(codec: Union[RTCRtpCodecCapability, RTCRtpCodecParameters]) -> bool:
return codec.name.lower() == "rtx"
init_codecs()
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