Controlling movie quality parameters

[VictorSeven]

First of all, thanks for sharing this package, it's awesome!

I am trying to produce movies that include stochastic noise. Fluctuations in the field do produce a lot of changes that due to video compression result in very poor quality videos.

Therefore I would like to increase the dpi and bitrate of the video in order to make the images more clear. In the docs I can see that the base Movie class do have options to control these, but apparently, I cannot feed bitrate as a parameter to other functions, such as movie. Maybe this can be accessed from plot_args but I don't know how to do it.

Documentation is not very clear about how to do this. Some things I have tried:

1. Using a MemoryStorage as written in docs, section 3. Result: produces an mp4 file and plays, but I cannot adjust the bitrate.

    storage = MemoryStorage()
    tracker = PlotTracker(interval=1.0, movie=mymovie, plot_args={"vmin":0, "vmax": 0.5, "figsize":(10,5)})
    sol = eq.solve(state, t_range=10.0, dt=1e-2, tracker=["progress", storage.tracker(1)])
    mymovie = movies.movie(storage, "pelicula.mp4", dpi=300, plot_args={"vmin":0, "vmax": 0.5})

2. Try to feed a Movie to a PlotTracker. Result: writes a file, but it cannot be read (I guess because of lack of MemoryStorage)

    mymovie = movies.Movie("pelicula.mp4", dpi=300, bitrate=100)
    tracker = PlotTracker(interval=1.0, movie=mymovie, plot_args={"vmin":0, "vmax": 0.5, "figsize":(10,5)})
    sol = eq.solve(state, t_range=10.0, dt=1e-2, tracker=tracker)

I guess there is an easy way to control movie parameters, but at least for me, it is not clear how to do this. I would appreciate some extra indications on how to increase bitrate and framerate. Thank you very much in advance!

[david-zwicker]

I agree that setting the details is a bit more complicated and might not be very well exposed in the current API. Your two approaches are very sensible and are close to working, as I will discuss in detail below.

1. You're right that the simple call to movies.movie does not allow you to set the bitrate (and plot_args). PR Allow setting more arguments in movie #203 fixes this, so in the future you should be able to use

storage = MemoryStorage()
sol = eq.solve(state, t_range=10.0, dt=1e-2, tracker=["progress", storage.tracker(1)])
mymovie = movies.movie(storage, "pelicula.mp4", plot_args={"vmin": 0, "vmax": 0.5},
                       movie_args={"dpi": 300, "bitrate": 2000})

2. The second approach is also feasible, but has one pitfall where the object mymovie needs to be closed after writing to it using the PlotTracker. You could do this by calling mymovie.save() after the last line. However, a better approach might be to use the following construct

with movies.Movie("pelicula.mp4", dpi=300, bitrate=100) as mymovie:
    tracker = PlotTracker(interval=1.0, movie=mymovie, plot_args={"vmin": 0, "vmax": 0.5, "figsize": (10, 5)})
    sol = eq.solve(state, t_range=10.0, dt=1e-2, tracker=tracker)

P.S: I converted the issue to a discussion, so it is better accessible in the future

[VictorSeven]

Thank you very much for your answer and the super-fast PR! I think the new arguments will be very useful. For now, however, I am using the second solution -which works perfectly too.