How can I calculate the bitrate and check the availability of an RTSP stream in Flutter without actually viewing the video?

In my Flutter project, I’m curious whether it’s feasible to determine the bitrate of a video from an RTSP URL. My idea is to connect to the RTSP URL and monitor the RTP data to figure out the stream’s bitrate. Is this approach viable?

The RTSP URL I have is formatted like this: rtsp://ip.ip.ip.ip:port/video1?key=token. As long as the camera is on, this stream is continuously active. I’d like to know how to check if this URL is accessible and assess its streaming speed without actually viewing the video content. Is there a way to do this in Flutter?

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Yes, your method is fundamentally sound. By connecting to the RTSP URL, you can track the stream’s data flow and calculate its bitrate. However, implementing this functionality in Flutter involves a few steps since Flutter doesn’t inherently support RTSP. You’ll need to utilize native platform channels to employ RTSP libraries that are compatible with iOS and Android.

Start by integrating an RTSP client in your native code, which will connect to the RTSP URL and start receiving the stream. To calculate the bitrate, measure the total data received over a specified time. The formula for this is: bitrate = (total bytes received * 8) / time in seconds.

For Android, libraries such as ‘LibVLC’ or ‘ExoPlayer’ with an RTSP extension can be used for receiving and processing the RTSP stream. You can then send the calculated data back to your Flutter app via platform channels. For iOS, you can achieve similar functionality using libraries like ‘MobileVLCKit’.

Thanks, that helps. Can you give more details on how to perform the bitrate calculation in the native code?

Yes, calculating the bitrate requires you to focus on two things: the volume of data received and the duration of time. In your native code (whether it’s Java/Kotlin for Android or Swift/Objective-C for iOS), you should set up a system to track the bytes received from the stream. At the same time, maintain a timer or timestamps to mark the beginning and end of your measurement period.

As your RTSP client reads the stream, increase a byte counter for every packet received. Upon reaching the end of your timer or at regular intervals, apply the aforementioned formula to calculate the bitrate. This information can then be communicated back to your Flutter application using platform channels.

That’s clear now. What about verifying if the RTSP URL is working?

To check the RTSP URL’s availability, your native code should try to connect to it. If the connection is established successfully and begins to receive data, it signifies that the URL is operational and accessible. You should consider implementing a timeout function to deal with situations where the connection attempt is unsuccessful or excessively delayed, as this could indicate problems with the URL or network.
You can then relay this connection status back to your Flutter app via platform channels, allowing for appropriate responses within your app’s interface or functionality.