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RTC Engine
Overview
  • Web
    • Run Sample Demo
    • SDK Quickstart
    • Basic Features
      • Screen Sharing
      • Live Streaming
      • Media Device
      • Audio Volume
      • Set Encoding Profile
      • Detect Network Quality
      • Detect Capabilities
    • Advance Features
      • Enable AI Denoiser
      • Enable Audio Mixer
      • Enable Watermark
      • Enable Beauty and Effects
      • Data Messages
      • Custom Capturing and Rendering
    • API List
    • Released Notes
    • Supported Platforms
    • Web FAQs
      • Optimize Multi-Person Video Calls
      • Handle Autoplay Restriction
      • Handle Firewall Restriction
      • Others
  • Android
    • Integration
      • 1.API Examples
      • 2.Importing the SDK
      • 3.Entering a Room
      • 4.Subscribing to Audio/Video Streams
      • 5.Publish Audio/Video Streams
      • 6.Exiting a Room
      • 7.Sensing Network Quality
      • 8.Enabling Screen Sharing
      • 9.Setting Video Quality
      • 10.Rotating Videos
    • Testing Newwork Quality
    • Custom Capturing and Rendering
    • Custom Audio Capturing and Playback
    • Client APIs
      • Overview
      • TRTCCloud
      • TRTCStatistics
      • TRTCCloudListener
      • TXAudioEffectManager
      • TXBeautyManager
      • TXDeviceManager
      • Type Definition
      • Deprecated Interface
      • Error Codes
    • Solution
      • Real-Time Chorus (TUIKaraoke)
        • Quick Integration
        • Implementation Steps
        • Song Synchronization
        • Lyric Synchronization
        • Vocal Synchronization
        • Mixing Stream Solution
        • TRTCKaraoke APIs
        • FAQs
    • Release Notes
  • iOS
    • Integration
      • 1.API Examples
      • 2.Importing the SDK
      • 3.Entering a Room
      • 4.Subscribing to Audio/Video Streams
      • 5.Publish Audio/Video Streams
      • 6.Exiting a Room
      • 7.Sensing Network Quality
      • 8.Enabling Screen Sharing
      • 9.Setting Video Quality
      • 10.Rotating Videos
    • Testing Network Quality
    • Custom Capturing and Rendering
    • Custom Audio Capturing and Playback
    • Client APIs
      • Overview
      • TRTCCloud
      • TRTCCloudDelegate
      • TRTCStatistics
      • TXAudioEffectManager
      • TXBeautyManager
      • TXDeviceManager
      • Type Definition
      • Deprecated Interface
      • ErrorCode
    • Solution
      • Quick Integration
      • Implementation Steps
      • Song Synchronization
      • Lyric Synchronization
      • Vocal Synchronization
      • Mixing Stream Solution
      • TRTCKaraoke APIs
      • FAQs
    • Release Notes
  • macOS
    • Integration
      • 1.API Examples
      • 2.Importing the SDK
      • 3.Entering a Room
      • 4.Subscribing to Audio/Video Streams
      • 5.Publish Audio/Video Streams
      • 6.Exiting a Room
      • 7.Sensing Network Quality
      • 8.Enabling Screen Sharing
      • 9.Sharing Computer Audio
      • 10.Setting Video Quality
      • 11.Rotating Videos
    • Testing Hardware Devices
    • Testing Network Quality
    • Custom Capturing and Rendering
    • Custom Audio Capturing and Playback
    • Client APIs
      • Overview
      • TRTCCloud
      • TRTCCloudDelegate
      • TRTCStatistics
      • TXAudioEffectManager
      • TXBeautyManager
      • TXDeviceManager
      • Type Definition
      • Deprecated Interface
      • ErrorCode
      • Release Notes
    • Release Notes
  • Windows
    • Integration
      • 1.API Examples
      • 2.Importing the SDK
      • 3.Entering a Room
      • 4.Subscribing to Audio/Video Streams
      • 5.Publish Audio/Video Streams
      • 6.Exiting a Room
      • 7.Sensing Network Quality
      • 8.Enabling Screen Sharing
      • 9.Setting Video Quality
      • 10.Rotating Videos
    • Testing Hardware Devices
    • Testing Network Quality
    • Custom Capturing and Rendering
    • Custom Audio Capturing and Playback
    • Client APIs
      • Overview
      • ITRTCCloud
      • ITRTCStatistics
      • TRTCCloudCallback
      • ITXAudioEffectManager
      • ITXDeviceManager
      • Type Definition
      • Deprecated Interface
      • Error Codes
    • Release Notes
  • Electron
    • Integration
      • 1.API Examples
      • 2.Importing the SDK
      • 3.Entering a Room
      • 4.Subscribing to Audio/Video Streams
      • 5.Publish Audio/Video Streams
      • 6.Exiting a Room
      • 7.Sensing Network Quality
      • 8.Enabling Screen Sharing
      • 9.Sharing Computer Audio
      • 10.Setting Video Quality
      • 11.Rotating Videos
    • Client APIs
      • Overview
      • Error Codes
  • Flutter
    • Integration
      • 1.API Examples
      • 2.Importing the SDK
      • 3.Entering a Room
      • 4.Subscribing to Audio/Video Streams
      • 5.Publish Audio/Video Streams
      • 6.Exiting a Room
      • 7.Sensing Network Quality
      • 8.Enabling Screen Sharing
      • 9.Sharing Computer Audio
      • 10.Setting Video Quality
      • 11.Rotating Videos
    • Client APIs
      • Overview
      • Error Codes
  • Unity
    • Integration
      • 1.API Examples
      • 2Importing the SDK
    • Client APIs
      • Overview
      • Error Codes
  • Qt
    • Integration
      • 1.Importing the SDK
  • Overview
    • Overview
  • Concepts
  • Features
  • Performance Statistics
  • Pricing
    • RTC-Engine Packages
    • Billing of On-Cloud Recording
    • Billing of MixTranscoding and Relay to CDN
    • Billing Explanation for Subscription Package Duration
    • Billing of Monitoring Dashboard
    • Free Minutes
    • Pay-As-You-Go
  • Tencent RTC Quickplay: Experience Ultimate Real-Time Audio and Video Interaction!
  • FAQs
    • FAQs for Beginners
    • Migration Guide
      • Twilio Video to Tencent RTC
      • Billing
      • Features
      • UserSig
      • Firewall Restrictions
      • How to Downsize Installation Package
      • TRTCCalling for Web
      • Audio and Video Quality
      • Others
RTC Engine

9.Setting Video Quality

Introduction

In TRTCCloud, you can adjust the video quality in the following ways:
TRTCAppScene in TRTCCloud.enterRoom: used to select your application scenario.
TRTCCloud.setVideoEncoderParam: used to set the encoding parameter.
TRTCCloud.setNetworkQosParam: used to set the network control policy.
This document describes how to configure these parameters to make the video quality of the TRTC SDK meet your project-specific needs. You can also see the following demos:

Supported Platforms

iOS
Android
macOS
Windows
Web
Electron
Flutter
For detailed directions on how to set video quality for the Web, please see Configuration Guide.

TRTCAppScene

VideoCall This corresponds to the scenario where most of the time there are two or more people on video calls, and the optimization for internal encoders and network protocols focuses on smoothness to reduce call latency and lagging.
LIVE This corresponds to the scenario where most of the time there is only one person speaking or performing and occasionally multiple people interact with one another through video, and the optimization for internal encoders and network protocols focuses on performance and compatibility to deliver better performance and definition.


TRTCVideoEncParam

Application Scenario
videoResolution
videoFps
videoBitrate
Video call (mobile)
640x360
15
550 Kbps
Video conferencing (primary image on macOS or Windows)
1280x720
15
1,200 Kbps
Video conferencing (primary image on mobile device)
640x360
15
900 Kbps
Video conferencing (small image)
320x180
15
250 Kbps
Online education (teacher on macOS or Windows)
960x540
15
850 Kbps
Online education (teacher on iPad)
640x360
15
550 Kbps
Online education (student)
320x180
15
250 Kbps

Detailed description of fields

(TRTCVideoResolution) videoResolution Encoded resolution; for example, 640x360 refers to the width (pixels) x height (pixels) of the encoded video image. In the TRTCVideoResolution enum definition, only landscape resolution (i.e., width >= height) is defined. If you want to use portrait resolution, you need to set resMode to Portrait.
notice
As many hardware codecs only support pixel widths that are divisible by 16, the actual resolution encoded by the SDK is not necessarily exactly the same as configured by the parameter; instead, it will be automatically corrected based on the divisor of 16; for example, the resolution 640x360 may be adapted to 640x368 inside the SDK.
(TRTCVideoResolutionMode) resMode This determines the landscape or portrait resolution. Because only landscape resolution is defined in TRTCVideoResolution, if you want to use portrait resolution such as 360x640, you need to specify resMode as TRTCVideoResolutionModePortrait. Generally, landscape resolution is used on PCs and Macs, while portrait resolution is used on mobile devices.
(int) videoFps Frame rate (FPS), which indicates how many frames are encoded per second. The recommended value is 15 FPS, which can ensure that the video image is smooth enough without reducing the video definition due to too many frames per second.
If you have high requirements for smoothness, you can set the frame rate to 20 or 25 FPS. However, please do not set a value above 25 FPS, because the normal frame rate of movies is only 24 FPS.
(int) videoBitrate Video bitrate, which indicates how many Kbits of encoded binary data is output by the encoder per second. If you set videoBitrate to 800 Kbps, the encoder will generate 800 Kbits of video data per second. If such data is stored as a file, the file size will be 800 Kbits, which is 100 KB or 0.1 MB.
A higher video bitrate is not always better; instead, it must have a proper mapping relationship with resolution as shown in the table below.

Resolution-bitrate reference table

Resolution Definition
Aspect Ratio
Recommended Bitrate(VideoCall)
Recommended Bitrate(LIVE)
TRTCVideoResolution_120_120
1:1
80 Kbps
120 Kbps
TRTCVideoResolution_160_160
1:1
100 Kbps
150 Kbps
TRTCVideoResolution_270_270
1:1
200 Kbps
300 Kbps
TRTCVideoResolution_480_480
1:1
350 Kbps
525 Kbps
TRTCVideoResolution_160_120
4:3
100 Kbps
150 Kbps
TRTCVideoResolution_240_180
4:3
150 Kbps
225 Kbps
TRTCVideoResolution_280_210
4:3
200 Kbps
300 Kbps
TRTCVideoResolution_320_240
4:3
250 Kbps
375 Kbps
TRTCVideoResolution_400_300
4:3
300 Kbps
450 Kbps
TRTCVideoResolution_480_360
4:3
400 Kbps
600 Kbps
TRTCVideoResolution_640_480
4:3
600 Kbps
900 Kbps
TRTCVideoResolution_960_720
4:3
1,000 Kbps
1,500 Kbps
TRTCVideoResolution_160_90
16:9
150 Kbps
250 Kbps
TRTCVideoResolution_256_144
16:9
200 Kbps
300 Kbps
TRTCVideoResolution_320_180
16:9
250 Kbps
400 Kbps
TRTCVideoResolution_480_270
16:9
350 Kbps
550 Kbps
TRTCVideoResolution_640_360
16:9
550 Kbps
900 Kbps
TRTCVideoResolution_960_540
16:9
850 Kbps
1,300 Kbps
TRTCVideoResolution_1280_720
16:9
1,200 Kbps
1,800 Kbps
TRTCVideoResolution_1920_1080
16:9
2,000kbps
3,000kbps

TRTCNetworkQosParam

QosPreference

If the network bandwidth is sufficient, both high definition and smoothness can be ensured; however, if the user's network connection is not ideal, should priority be given to definition or smoothness? You can make a choice by specifying the preference parameter in TRTCNetworkQosParam.
Smoothness preferred (TRTCVideoQosPreferenceSmooth) Smoothness is ensured on a weak network, while the video image will have a lot of blurs but can be smooth with no or slight lagging.
Definition preferred (TRTCVideoQosPreferenceClear) Definition is ensured on a weak network, i.e., the image will be as clear as possible but tend to lag.

ControlMode

For the controlMode parameter, select TRTCQosControlModeServer. TRTCQosControlModeClient is used for internal debugging by the Tencent Cloud R&D team and should be ignored.

Common Misunderstandings

1. The higher the resolution, the better?
Higher resolutions require higher bitrates for support. If the resolution is 1280x720, but the bitrate is specified as 200 Kbps, the video image will have a lot of blurs. We recommend that you set it as described in the Resolution-bitrate reference table.
2. The higher the frame rate, the better?
Because the image captured by the camera is a complete mapping to all real objects in the exposure phase, it is not that the higher the frame rate, the smoother the video, which is different from the concept of FPS in games. On the contrary, if the frame rate is too high, the quality of each video frame will be lowered, and the exposure time of the camera will be reduced, worsening the image effect.
3. The higher the bitrate, the better?
4. Higher bitrates also require higher resolutions for a match. For a resolution of 320x240, a 1,000 Kbps bitrate would be wasteful. We recommend that you set it as described in the Resolution-bitrate reference table.
5. High resolution and bitrate can be set when connected to a Wi-Fi network?
It is not that the Wi-Fi network speed is constant. If the device is far from the wireless router or the router channel is occupied, the Wi-Fi network may not be as fast as 4G. In response to this issue, the TRTC SDK provides a speed test feature, which can perform speed test to determine the network quality based on the score before a video call is established.