Menu
All browsers currently implement HTML5 <video> frame-seeking API as time divisions. e.g. In a video of 10fps, Frame #10 is time=1.0 seconds. Thus, if you want to be able to frame-seek accurately, i.e. advance one frame forward, you need to go to time=1.1 seconds. This frame-to-time calculation is done by knowing the video's frame rate (fps).
However, I don't know how the browsers calculate the frame rate.
They either read the video file's container information for some fps property, or calculate it on their own.
By using FFmpeg, you can get that by FFmpeg -i video.avi which returns Stream #0.0: Video: libvpx, yuv420p, 512x288, PAR 1:1 DAR 16:9, 25 fps, 25 tbr, 1k tbn, 25 tbc , and you can see the fps there.
The question is: Is this accurate? If not, is there an accurate way of calculating this? I just want to mimic the browsers so I can frame-seek accurately.
853
To calculate frames per second, you just take the number of rendered frames and divide it by the seconds passed.
The requestVideoFrameCallback() method allows web authors to register a callback that runs in the rendering steps when a new video frame is sent to the compositor.
In the quality menu, high frame rate will be listed next to the resolution. For example, a 1080p resolution video at 120 frames per second (FPS) will be listed as 1080p60. Note: Uploading and watching videos at 120 FPS is not supported at this time.
The framerate of a video isn't calculated, it's stored as part of the video's metadata. There's just a field in the video's header that says how many frames per second (or possibly the amount of time each frame is shown). It's the same way the browser knows the video's resolution.
116
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
