The text/BRIAN DIPERT
Original link/blog.addpipe.com/typical-vid…
We were recently asked about video bitrate versus file size: Is there a typical file size for low, medium, and high quality, such as a 1-minute video response?
My immediate answer is that it depends on many factors, but then I realized THAT I should try to mine the data. In our large data set, we should look for some typical bit rates, especially when dealing with large volumes of data.
We have looked at two mechanisms for capturing video from users and the bit rates they generate:
1.MediaStream Recording API: used by our (inline) desktop Recording client
2.HTML Media Capture: used by our local mobile recording client
MediaStream Recording API
Since this API allows you to request resolutions from your webcam, we looked at 3 typical resolutions that should be supported by most USB/ integrated webcams:
320×240 640×480 1280×720 We pulled the first 10,000th video recorded at that resolution in 2021 from our database and filtered it further through browsers (Chrome and Firefox).
For 320×240 video:
The 5691 videos recorded using Chrome had an average bit rate of 183 KB /s. The average bit rate for more than 374 videos recorded using Firefox was 2 Mb/s. I suspect the difference in bitrate is mainly because Firefox (only) uses VP8 to compress video data, while Chrome uses H.264.
Also, we don’t have user agent information for all the videos, which is why the total number of videos doesn’t add up to 10,000.
For 640×480 resolution video:
More than 7,501 videos recorded using Chrome had an average bit rate of 589 KB /s. The average bit rate for more than 181 videos recorded using Firefox was 2.64 Mb/s.
For 1280×720 video:
More than 6956 videos recorded using Chrome had an average bit rate of 1.97 Mb/s. The average bit rate for more than 1265 videos recorded using Firefox was 2.69 Mb/s. With HD recording, there is room for differences in camera quality and lighting Settings (noisy images in low-light environments are difficult to encode efficiently)
You’ll see two parallel chrome lines near the 2Mbits/s mark. The top is Chrome for Windows, and the bottom is Chrome for macOS. I could be wrong, but I suspect they use a different H.264 encoder. If not, there is a FaceTime camera on every macOS device.
Below is Chrome data by operating system.
HTML Media Capture
This API allows you to capture audio and video depending on the application and functionality of the operating system. It works with Android and iOS/iPadOS (but not just for audio recording).
You cannot control or specify resolution using HTML Media Capture, but we know from past experience that:
On iOS and iPadOS, you can get 480×360 (and its vertical variation) when you record live or 1280×720 (and its vertical variation) when you select a record from the library. On Android, you can get any record of your device’s configuration (unlike forced compression on iOS/iPad OS).
iOS & iPadOS
So you can see:
1. 894kbits/s(and 480×360 resolution) when capturing live video
2.69 Mbits/s(and 1280×720) when selecting a pre-recorded video in the library
3. The average is 1.8 Mbits/s
We also looked at the number of videos obtained from iOS/iPadOS via HTML Media Capture that differed in resolution from 480×360, 1280×720, and their vertical variants. Out of 10,000 videos, only 548 have different resolutions.
Android
Using HTML Media Capture on Android, you can get anything configured on your device. So we’re seeing quite a bit of 4K video. Since you can’t ask for a specific resolution, we only calculated an average resolution of 12.9 Mbits/s for all 10K videos.
This is the same data, but sorted by bit rate to better see the grouping around the 20 Mbits/s mark.
These numbers are very relevant to the data from the browser. After processing the files and transcoding some of the data, the numbers may be different. For example, we converted VP8 video data from Firefox to H.264 and Opus audio data to AAC.