TVIEncodingParameters Class Reference

Inherits from	NSObject
Declared in	TVIEncodingParameters.h

Overview

TVIEncodingParameters defines audio and video encoding parameters.

Maximum bitrate is specified as Transport Independent Application Specific Maximum (TIAS) bitrate RFC3890 in Kilobits per second (Kbps) excluding IP/UDP/TCP headers. These encoding parameters are applied for each PeerConnection. For peer-to-peer Rooms, there is a separate PeerConnection for each participant, i.e., if you set the maximum video bitrate to 1,000 Kbps and you have two TVIRemoteParticipants in the Room, the SDK sends up to 2,000 Kbps. For group Rooms, there is a single PeerConnection to Twilio’s Media Server.

If you are publishing multiple video tracks (e.g., video and screen share), each track receives up to the maximum bitrate specified, i.e., if you set the maximum video bitrate to 1,000 Kbps and you publish both video and screen Tracks, the SDK sends at most 2,000 Kbps. You may update encoding parameters any time using [TVILocalParticipant setEncodingParameters:].

`– initWithAudioBitrate:videoBitrate:`

Initializes a TVIEncodingParameters object.

- (_Nonnull instancetype)initWithAudioBitrate:(NSUInteger)maxAudioBitrate videoBitrate:(NSUInteger)maxVideoBitrate

Parameters

`maxAudioBitrate`	The maximum audio send bitrate in Kilobits per second (Kbps).
`maxVideoBitrate`	The maximum video send bitrate in Kilobits per second (Kbps).

Return Value

A TVIEncodingParameters instance.

Discussion

Audio and video encoding parameters. Maximum bitrate is specified as Transport Independent Application Specific Maximum (TIAS) bitrate RFC3890 in kilobits per second (kbps) excluding IP/UDP/TCP headers. Maximum bitrate applies to variable bitrate codecs and is limited to 100 Mbps.

Note: These encoding parameters are applied for each peer connection, each track and each simulcast layer.

For group Rooms, there is a single peer connection to Twilio Media Server, but for peer-to-peer Rooms, there is a separate peer connection for each participant. I.e., if you set maximum video bitrate to 1 Mbps and you have two TVIRemoteParticipant in the Room, the effective video send bitrate may be up to 2 Mbps.

If you are publishing multiple video tracks (e.g. camera and screen share), each track receives the maximum bitrate specified. I.e. if you set maximum video bitrate to 1 Mbps and you publish both a camera and a screen share track, the effective video send bitrate may be up to 2 Mbps.

If simulcast is used for video tracks, each simulcast layer receives the maximum bitrate specified. i.e. if your set the maximum bitrate to 1 Mbps and you publish a simulcast video track, the effective video send bitrate may be up to 3 Mbps if there are three simulcast layers.

The codec used also affects the bitrate. Each codec type has a minimum and maximum bitrate, and the bitrate used for a track will always be between those values, even if a higher or lower bitrate is specified here.

Encoding parameters can be updated any time, using TVILocalParticipant::setEncodingParameters

Please note that values reported by statistics API will be higher due to packetization overhead etc.

Declared In

TVIEncodingParameters.h

`maxAudioBitrate`

Maximum audio send bitrate in Kilobits per second.

@property (nonatomic, assign, readonly) NSUInteger maxAudioBitrate

Discussion

Zero indicates the WebRTC default value, which is codec dependent. The maximum bitrate for Opus is 510 Kbps.

Declared In

TVIEncodingParameters.h

`maxVideoBitrate`

Maximum video send bitrate in Kilobits per second.

@property (nonatomic, assign, readonly) NSUInteger maxVideoBitrate

Discussion

Zero indicates the WebRTC default value, which is 2000 Kbps. The bitrate limit is applied individually to each video track and, if simulcast is used, to each simulcast layer.

Declared In

TVIEncodingParameters.h