Mixed-stream recording

We currently support the following cloud recording modes:

Single-stream recording: All the audio, video streams, and whiteboard recordings in a room are recorded in separate files.
Mixed-stream recording: The audio, video streams, and whiteboard recordings in a room are recorded in a single file.

This document describes how to implement mixed-stream recording by using the cloud recording APIs.

Implementation

To use the mixed-stream recording, call the StartRecord method, and set the RecordMode parameter to 2.

You can select the format of the recorded file as needed by setting the OutputFileFormat parameter to mp4, flv, or hls.

For instance, set the OutputFileFormat parameter to mp4, and the generated recordings are varies based on the content to be recorded:

Content to be recorded	Parameter	Recorded file
Audio only	Set `StreamType` to "1"	The audio streams of all stream IDs are recorded in a single mp4 file.
Video only	Set `StreamType` to "2"	The video streams and whiteboard recordings of all stream IDs are recorded in a single mp4 file.
Audio and video (mixed)	Set `StreamType` to "3"	The audio, video streams, and the whiteboard recordings of all stream IDs are recorded in a single mp4 file.
Record audio and video (separate)	Set `StreamType` to "4"	The audio, video streams, and the whiteboard recordings of all stream IDs are recorded in an mp4 and an aac file. The mp4 file contains the video and whiteboard data, and the aac file contains the audio data.

In the mixed-stream recording, you will need to set the resolution, frame rate, bitrate of the output video with the MixOutputVideoConfig parameter. We recommend you refer to the following table:

Warning

Higher resolution is not always better. We recommend not to set a higher resolution than the original video stream; otherwise, the final recorded file may be blurry.
The resolution here refers to the resolution of the video canvas in mixed-stream recording mode, and its aspect ratio does not need to be consistent with the original video. The aspect ratio of the user video image in the output video depends on the aspect ratio of the video canvas and the mixed-stream layout.
The bitrates in the following table vary according to different scenarios. A larger bitrate is usually required in live streaming scenarios to improve video quality, which is about twice that of the communications scenario.

Resolution (width * height)	Frame rate (fps)	Bitrate for communications (bps)	Bitrate for live streaming (bps)
160 * 120	15	65,000	130,000
120 * 120	15	50,000	100,000
320 * 180	15	140,000	280,000
180 * 180	15	100,000	200,000
240 * 180	15	120,000	240,000
320 * 240	15	200,000	400,000
240 * 240	15	140,000	280,000
424 * 240	15	220,000	440,000
640 * 360	15	400,000	800,000
360 * 360	15	260,000	520,000
640 * 360	30	600,000	1,200,000
360 * 360	30	400,000	800,000
480 * 360	15	320,000	640,000
480 * 360	30	490,000	980,000
640 * 480	15	500,000	1,000,000
480 * 480	15	400,000	800,000
640 * 480	30	750,000	1,500,000
480 * 480	30	600,000	1,200,000
848 * 480	15	610,000	1,220,000
848 * 480	30	930,000	1,860,000
640 * 480	10	400,000	800,000
1280 * 720	15	1,130,000	2,260,000
1280 * 720	30	1,710,000	3,420,000
960 * 720	15	910,000	1,820,000
960 * 720	30	1,380,000	2,760,000
1920 * 1080	15	2,080,000	4,160,000
1920 * 1080	30	3,150,000	6,300,000

Sample request

Content-type: application/json;charset=utf-8

The request example of StartRecord is as follows:

Untitled

{
	"RoomId": "xxxx",
	"RecordInputParams": {
		"RecordMode": 2,
		"StreamType": 3,
		"MaxIdleTime": 60,
		"MixConfig": {
			"MixMode": 2,
			"MixOutputStreamId": "mix",
			"MixOutputVideoConfig": {
                "Width": 1280, 
                "Height": 720, 
                "Fps": 15, 
                "Bitrate": 1130000
        }
		}
	},
	"RecordOutputParams": {
		"OutputFileFormat": "mp4",
		"OutputFolder": "record/"
	},
	"StorageParams": {
		"Vendor": 2,
		"Region": "oss-xxxx",
		"Bucket": "xxxx",
		"AccessKeyId": "xxxx",
		"AccessKeySecret": "xxxx"
	}
}

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