A method of synthesizing audio/video for application on an audio/video synthesis system, the audio/video synthesis system is deployed on a cloud server, the method comprising: receiving video synthesis instructions sent by a broadcast client, synthesizing a first video stream based on multiple video input streams, and synthesizing a second video stream based on the multiple video input streams and the first video stream; in response to the video synthesis instructions, determining one or more target video input streams from the multiple video input streams and integrating the video pictures of the one or more target video input streams into one video picture, wherein a video stream corresponding to the integrated video picture which includes the video pictures of the one or more target video input streams is used as the first video stream; and integrating the video picture of the first video stream and the video pictures of the multiple video input streams into one video picture, wherein a video stream corresponding to the integrated video picture which includes the video picture of the first video stream and the video pictures of the multiple video input streams is used as the second video stream; receiving audio synthesis instructions from the broadcast client and respectively synthesizing a first audio stream and a second audio stream based on multiple audio input streams; respectively encoding the first video stream, the second video stream, the first audio stream and the second audio stream in multiple different encoding versions to correspondingly obtain a first video encoding stream set, a second video encoding stream set, a first audio encoding stream set and a second audio encoding stream set; respectively selecting a first video encoding stream and a first audio encoding stream from the first video encoding stream set and the first audio encoding stream set, and integrating the first video encoding stream and the first audio encoding stream into a first output stream, and providing the first output stream to a user client; and respectively selecting a second video encoding stream and a second audio encoding stream from the second video encoding stream set and the second audio encoding stream set, and integrating the second video encoding stream and the second audio encoding stream into a second output stream, and providing the second output stream to the broadcast client. receiving video synthesis instructions sent by a broadcast client, synthesizing a first video stream based on multiple video input streams, and synthesizing a second video stream based on the multiple video input streams and the first video stream; in response to the video synthesis instructions, determining one or more target video input streams from the multiple video input streams and integrating the video pictures of the one or more target video input streams into one video picture, wherein a video stream corresponding to the integrated video picture which includes the video pictures of the one or more target video input streams is used as the first video stream; and integrating the video picture of the first video stream and the video pictures of the multiple video input streams into one video picture, wherein a video stream corresponding to the integrated video picture which includes the video picture of the first video stream and the video pictures of the multiple video input streams is used as the second video stream; receiving audio synthesis instructions from the broadcast client and respectively synthesizing a first audio stream and a second audio stream based on multiple audio input streams; respectively encoding the first video stream, the second video stream, the first audio stream and the second audio stream in multiple different encoding versions to correspondingly obtain a first video encoding stream set, a second video encoding stream set, a first audio encoding stream set and a second audio encoding stream set; respectively selecting a first video encoding stream and a first audio encoding stream from the first video encoding stream set and the first audio encoding stream set, and integrating the first video encoding stream and the first audio encoding stream into a first output stream, and providing the first output stream to a user client; and respectively selecting a second video encoding stream and a second audio encoding stream from the second video encoding stream set and the second audio encoding stream set, and integrating the second video encoding stream and the second audio encoding stream into a second output stream, and providing the second output stream to the broadcast client.