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AC Replay Size Estimator 1.0

Estimate the replay size so you can better choose the Quality setting

  1. luchian

    When it comes to replay saving, Assetto Corsa is a little specific - not only in the way it's doing it (nowadays in a continuous file, with all sessions combined) but also regarding the huge amount of memory it needs. To somehow help in this regard, Stefano added the functionality of setting the replay quality on different levels - from very low to ultra. But what does that mean ?

    Thanks to the info shared by AC forum user Stereo, we now have some close estimates. To make the task easier, I have created a small excel file to help with the calculations.

    How it looks:

    The INFO ZONE, is there just to give you an idea about basic data in AC. The figures might not be 100% accurate (as far as I know there is no official information about it) but they are pretty close so serve our purpose.

    The difference between replay quality levels seems to be the frequency essential parameters are recorded. For each car. By essential parameters we mean car position and angle of rotation (wheels, suspensions, etc.), lap times, telemetry info (speed, steering/brake position, etc.), gear, and other info (like headlights on, for example).

    The frequency the above information is recorded, varies from 64 (for ultra) to 8 (for very low) times/second.

    The OUTPUT ZONE, will give you estimates about memory usage. Either an estimated size in Mb (based on your input), either an estimate of maximum recording time (again, based on your input) supposing in Options you put the slider on max (1000 Mb).

    The file is protected (pwd: 2016) just to avoid accidental edit. By default, you can only input data in.. wait for it.. YOUR INPUT HERE, as follows :
    => number of cars (including yours). If in MP, you need to enter the total number of cars in server config, not only those in use at a specific time.
    => number of movable objects on track - if you don't know 15 might be a fair assumption (at least for official tracks - as I recall Simone was saying)
    => target time to record (in minutes) - use this if you already know an estimate length of your session (like in a league race) and wish to estimate the memory it will take - hence, helping you decide if you should go for low, med, high, ultra.
    => server refresh rate - optional parameter. It is not used directly in the calculations, but it's relevant to know. Example: it would make no sense setting the replay quality to high (32 Hz), if the server refresh rate is 16 or lower. It would try to record more information than actually available, so it would have no benefit and would occupy memory for nothing. NOTE: in server config, the line responsible for this is called CLIENT_SEND_INTERVAL_HZ= X.

    Final thoughts:
    - final estimates are not 100% accurate. However, by the tests I have done they seem to fall within +/- 10%, so still very useful. Anyways, take a bit of margin :).
    - having compared replays with low to ultra settings, visually there isn't much of a difference. Because AC would use the values recorded in replay as "key frames", and interpolate the rest. And it does that very well in my opinion. Now of course, if you are plan doing some destruction derby, you might want to crank that to ultra and capture as much detail as possible. But for casual, normal racing, med is very good already.
    - should you notice any errors, or learn something new, please don't hesitate to post here.
    - hope you find this useful, enjoy :).