Quickblox - How to save a QBRTCCameraCapture to a file

In the process of developing applications with Quickblox, a common requirement related to video communication is to save video call data to files for later playback or archiving. Quickblox provides various tools and interfaces to support video stream processing, but directly saving QBRTCCameraCapture to a file requires additional processing. Below, I will detail the possible methods to achieve this functionality.

Method Overview

1. Capture Video Frames: Use QBRTCCameraCapture to capture video frames. This is a tool provided by Quickblox for capturing video data from the device's camera.
2. Video Frame Processing: Convert captured video frames into formats suitable for file storage. Common formats include YUV, NV12, or direct conversion to H.264 encoding (if compression is needed).
3. Encoding and Saving: Use an appropriate encoder to encode video frames and write the encoded data to the file system.

Specific Implementation Steps

Step 1: Initialize QBRTCCameraCapture

First, initialize QBRTCCameraCapture. This involves setting the capture resolution and frame rate.

swift
let videoFormat = QBRTCVideoFormat()
videoFormat.frameRate = 30
videoFormat.pixelFormat = QBRTCPixelFormatFormat420f
videoFormat.width = 640
videoFormat.height = 480

let cameraCapture = QBRTCCameraCapture(videoFormat: videoFormat, position: .front)
cameraCapture.startSession()

Step 2: Capture and Process Video Frames

In QBRTCCameraCapture, set a delegate to capture video frames. Whenever a new frame is captured, it is passed through this delegate method.

swift
extension YourClass: QBRTCVideoCaptureDelegate {
    func capture(_ capture: QBRTCCameraCapture, didCaptureVideoFrame videoFrame: QBRTCVideoFrame) {
        // Process the video frame data here
    }
}

Step 3: Encode Video Frames

Next, use a video encoder to encode the frames. AVAssetWriter can be used for H.264 encoding.

swift
let writer = try AVAssetWriter(outputURL: fileUrl, fileType: .mp4)
let videoSettings = [
    AVVideoCodecKey: AVVideoCodecType.h264,
    AVVideoWidthKey: 640,
    AVVideoHeightKey: 480
]
let writerInput = AVAssetWriterInput(mediaType: .video, outputSettings: videoSettings)
writer.add(writerInput)

writer.startWriting()
writer.startSession(atSourceTime: CMTime.zero)

// Write frame data
writerInput.append(sampleBuffer)

Step 4: Complete Encoding and Save the File

When the video call ends, terminate the file writing session.

swift
writerInput.markAsFinished()
writer.finishWriting {
    // File saved
}

Example

In practical applications, you may also need to handle audio data or adjust video quality under unstable network conditions. Additionally, error handling and performance optimization are important considerations during development.

This is a basic workflow for using Quickblox to save QBRTCCameraCapture to a file. I hope this is helpful for your project. If you have any questions, I'm happy to discuss further.