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package webrtc
import (
"strings"
)
// RTPCodecType determines the type of a codec
type RTPCodecType int
const (
// RTPCodecTypeAudio indicates this is an audio codec
RTPCodecTypeAudio RTPCodecType = iota + 1
// RTPCodecTypeVideo indicates this is a video codec
RTPCodecTypeVideo
)
func (t RTPCodecType) String() string {
switch t {
case RTPCodecTypeAudio:
return "audio"
case RTPCodecTypeVideo:
return "video" //nolint: goconst
default:
return ErrUnknownType.Error()
}
}
// NewRTPCodecType creates a RTPCodecType from a string
func NewRTPCodecType(r string) RTPCodecType {
switch {
case strings.EqualFold(r, RTPCodecTypeAudio.String()):
return RTPCodecTypeAudio
case strings.EqualFold(r, RTPCodecTypeVideo.String()):
return RTPCodecTypeVideo
default:
return RTPCodecType(0)
}
}
// RTPCodecCapability provides information about codec capabilities.
//
// https://w3c.github.io/webrtc-pc/#dictionary-rtcrtpcodeccapability-members
type RTPCodecCapability struct {
MimeType string
ClockRate uint32
Channels uint16
SDPFmtpLine string
RTCPFeedback []RTCPFeedback
}
// RTPHeaderExtensionCapability is used to define a RFC5285 RTP header extension supported by the codec.
//
// https://w3c.github.io/webrtc-pc/#dom-rtcrtpcapabilities-headerextensions
type RTPHeaderExtensionCapability struct {
URI string
}
// RTPHeaderExtensionParameter represents a negotiated RFC5285 RTP header extension.
//
// https://w3c.github.io/webrtc-pc/#dictionary-rtcrtpheaderextensionparameters-members
type RTPHeaderExtensionParameter struct {
URI string
ID int
}
// RTPCodecParameters is a sequence containing the media codecs that an RtpSender
// will choose from, as well as entries for RTX, RED and FEC mechanisms. This also
// includes the PayloadType that has been negotiated
//
// https://w3c.github.io/webrtc-pc/#rtcrtpcodecparameters
type RTPCodecParameters struct {
RTPCodecCapability
PayloadType PayloadType
statsID string
}
// RTPParameters is a list of negotiated codecs and header extensions
//
// https://w3c.github.io/webrtc-pc/#dictionary-rtcrtpparameters-members
type RTPParameters struct {
HeaderExtensions []RTPHeaderExtensionParameter
Codecs []RTPCodecParameters
}
type codecMatchType int
const (
codecMatchNone codecMatchType = 0
codecMatchPartial codecMatchType = 1
codecMatchExact codecMatchType = 2
)
// Do a fuzzy find for a codec in the list of codecs
// Used for lookup up a codec in an existing list to find a match
// Returns codecMatchExact, codecMatchPartial, or codecMatchNone
func codecParametersFuzzySearch(needle RTPCodecParameters, haystack []RTPCodecParameters) (RTPCodecParameters, codecMatchType) {
// First attempt to match on MimeType + SDPFmtpLine
// Exact matches means fmtp line cannot be empty
for _, c := range haystack {
if strings.EqualFold(c.RTPCodecCapability.MimeType, needle.RTPCodecCapability.MimeType) &&
c.RTPCodecCapability.SDPFmtpLine == needle.RTPCodecCapability.SDPFmtpLine {
return c, codecMatchExact
}
}
// Fallback to just MimeType if either haystack or needle does not have fmtpline set
for _, c := range haystack {
if strings.EqualFold(c.RTPCodecCapability.MimeType, needle.RTPCodecCapability.MimeType) &&
(c.RTPCodecCapability.SDPFmtpLine == "" || needle.RTPCodecCapability.SDPFmtpLine == "") {
return c, codecMatchPartial
}
}
return RTPCodecParameters{}, codecMatchNone
}
|
