CSS provides live stream mix feature, which can synchronously mix multiple streams of input sources into a new stream based on the configured stream mix layout for interactive live streaming. In addition, on-cloud stream mix has been connected to TencentCloud API 3.0. For more information, please see CreateCommonMixStream. This document uses examples to describe how to implement live stream mix in different scenarios.

Notes

• Standard transcoding fees will be incurred for the stream mix feature.
• To use the mixing and cropping feature, the value of cropping parameter cannot exceed the value of input stream parameter.

Supported Features

• Up to 16 concurrent streams can be mixed.
• Up to 5 types of input sources (audio and video, pure audio, pure video, image, and canvas) can be mixed.
• Mixed streams can be output as a new stream.
• Cropping and watermarking are supported.
• Template configuration is supported.
• Recording based on stream mix is supported.
• Automatic stream mix is supported.
• Stream mix types and positions can be switched in real time.
• Stream mix can be started/canceled seamlessly.

Common Layout Templates

Common templates include 10, 30, 40, 310, 390, 410, 510, and 610. When using them, you do not need to enter the position and length/width parameters of the input stream, and the original image will be scaled proportionally. You only need to pass in the template ID.

Figures of common layout templates:

Template 10	Template 30
Template 40	Template 310
Template 390	Template 410
Template 510	Template 610

Creating a Stream Mix

Parameter Description

For more information, please see CreateCommonMixStream.

Scenario 1. Apply for stream mix - use template 20

This example shows you how to use a preset stream mix template to mix streams.

Sample input code

https://live.tencentcloudapi.com/?Action=CreateCommonMixStream
&MixStreamSessionId=test_room
&MixStreamTemplateId=20
&OutputParams.OutputStreamName=test_stream1
&InputStreamList.0.InputStreamName=test_stream1
&InputStreamList.0.LayoutParams.ImageLayer=1
&InputStreamList.1.InputStreamName=test_stream2
&InputStreamList.1.LayoutParams.ImageLayer=2
&<Common request parameters>

Sample output code

{
  "Response": {
    "RequestId": "e8fa8015-0892-40d5-95c4-12a4bc06ed31"
  }
}

Stream mix effect for mic connection

Scenario 2. Apply for stream mix - use template 390

This example shows you how to use a preset stream mix template to mix streams.

Sample input code

https://live.tencentcloudapi.com/?Action=CreateCommonMixStream
&MixStreamSessionId=test_room
&MixStreamTemplateId=390
&OutputParams.OutputStreamName=test_stream2
&InputStreamList.0.InputStreamName=test_stream1
&InputStreamList.0.LayoutParams.ImageLayer=1
&InputStreamList.0.LayoutParams.InputType=3
&InputStreamList.0.LayoutParams.ImageWidth=1920  (canvas width)
&InputStreamList.0.LayoutParams.ImageHeight=1080 (canvas height)
&InputStreamList.0.LayoutParams.Color=0x000000
&InputStreamList.1.InputStreamName=test_stream2
&InputStreamList.1.LayoutParams.ImageLayer=2
&InputStreamList.2.InputStreamName=test_stream3
&InputStreamList.2.LayoutParams.ImageLayer=3
&<Common request parameters>

Sample output code

{
  "Response": {
    "RequestId": "9d8d5837-2273-4936-8661-781aeab9bc9c"
  }
}

Stream mix effect for host competition

Scenario 3. Custom stream mix

Use the custom layout, where the position parameters LocationX and LocationY represent the absolute pixel distance between the top-left corner of the small image and that of the background image.

Sample input code

https://live.tencentcloudapi.com/?Action=CreateCommonMixStream
&MixStreamSessionId=test_room
&OutputParams.OutputStreamName=test_stream2
&InputStreamList.0.InputStreamName=test_stream1
&InputStreamList.0.LayoutParams.ImageLayer=1
&InputStreamList.0.LayoutParams.InputType=3
&InputStreamList.0.LayoutParams.ImageWidth = 1920
&InputStreamList.0.LayoutParams.ImageHeight= 1080
&InputStreamList.0.LayoutParams.Color=0x000000
&InputStreamList.1.InputStreamName=test_stream2
&InputStreamList.1.LayoutParams.ImageLayer=2
&InputStreamList.1.LayoutParams.ImageWidth = 640
&InputStreamList.1.LayoutParams.ImageHeight= 360
&InputStreamList.1.LayoutParams.LocationX= 50
&InputStreamList.1.LayoutParams.LocationY= 720
&InputStreamList.2.InputStreamName=test_stream3
&InputStreamList.2.LayoutParams.ImageLayer=3
&InputStreamList.2.LayoutParams.ImageWidth = 640
&InputStreamList.2.LayoutParams.ImageHeight= 360
&InputStreamList.2.LayoutParams.LocationX= 740
&InputStreamList.2.LayoutParams.LocationY= 720
&<Common request parameters>

Sample output code

{
  "Response": {
    "RequestId": "8c443359-ba07-4b81-add8-a6ff54f9bf54"
  }
}

Custom stream mix effect

Canceling a Stream Mix

Parameter description

For more information, please see CancelCommonMixStream.

Examples

Cancel a stream mix based on SessionId.

Sample input code

https://live.tencentcloudapi.com/?Action=CancelCommonMixStream
&MixStreamSessionId=test_room

Sample output code

{
  "Response": {
    "RequestId": "3c140219-cfe9-470e-b241-907877d6fb03"
  }
}

Note：

• The stream mix you apply for cannot be cancelled within 5 seconds.
• After the cancellation, you can apply for a stream mix with the same SessionId at least 30 seconds later.

Error Codes

For on-cloud stream mix API 3.0, most common error codes have been transformed into the style of API 3.0 error code. However, some error codes remain unchanged, which will be provided in the format of err_code [ $code ],msg [ $message ] in Message and prompted as an InvalidParameter error. The causes of specific codes are as detailed below:

FAQs

• Why does the stream mix after push return the error code 505?
• What happens if the applied stream mix is not canceled?
• Why does the assistant host image of the stream mix sometimes appear at the unexpected position?

Note：

For more questions about on-cloud stream mix, see On-cloud Stream Mix FAQs