Get a time estimate while waiting for your video

[veltman]

Current status updates tell you what stage the rendering is at and % progress, but it would be nice to get a full waiting time estimate, especially if you're in a queue with jobs in front of you. This would entail some formula for estimated completion time, which would require knowing the duration before a job has started, so we'd probably have to send a duration estimate from the browser. Then we could multiply the duration and framerate by some conservative per-frame estimate.

[Laurian]

ffmpeg has a -progress URL option, where progress info is HTTP POST-ed (chunked), that could feed into express and relayed further to the user

[veltman]

The FFmpeg processing time is only a small fraction of the total time, the main issue is drawing the frames. The steps to an estimate would basically be:

1. Include a selectedDuration value in each job when it's submitted.
2. Keep a moving average of how long each step takes per second of length.
3. Use those per-second benchmarks to estimate how long each step a job of X seconds will take.
4. To compute the ETA of a job, add up the estimated time of the remaining steps for in-progress jobs (if queued), plus the estimated time of the remaining steps for the job itself.

Steps 2 and 3 could be skipped in favor of a rough estimate based on system stats detected by os.cpus() and os.totalmem().

[Laurian]

Yup, I'm digging into FFmpeg progress for other projects, the HTTP chunked POST it can make is messy to listen to, looking now at https://github.com/eugeneware/ffmpeg-progress-stream