Python script for blending video frames together. http://toystoryblended.blogspot.com/

blend_video.py

from scipy import misc
import numpy as np
import multiprocessing as mp
import os

# number of frames to combine when producing 1 output frame
FRAME_LIMIT = 300
# input and output directories
INDIR = 'ts1'
OUTDIR = '%s_300avg' % INDIR

infiles = os.listdir(INDIR)
# filters files in input directory to only include those starting with "image" and ending with ".png"
infiles = sorted((x for x in infiles if x.startswith('image') and x.endswith('.png')))
NUM_FRAMES = len(infiles)

frame1 = misc.imread(os.path.join(INDIR, infiles[0]))


def avg_frames(frames):
    """Calculates and returns the average of input list of frames, using pyramid-like weighting"""
    avg_frame = np.zeros(frame1.shape, dtype=float)
    adj_factor = FRAME_LIMIT / 2;
    for idx, filename in enumerate(frames):
        im = misc.imread(os.path.join(INDIR, filename))
        avg_frame += im * (1. - float(abs(adj_factor - idx))/adj_factor) / adj_factor
    return avg_frame

def make_frame(inframes, idx):
    """Saves average of input frames to file"""
    frame = avg_frames(inframes)
    misc.imsave('%s/frame%04d.png' % (OUTDIR, idx), frame)

def get_frames(framenum, infiles):
    """Gets frames within FRAME_LIMIT/2 on either side of the indicated frame number (wraps around beginning/end)"""
    if framenum < FRAME_LIMIT/2:
        frames = infiles[(framenum - FRAME_LIMIT/2):]
        frames.extend(infiles[:framenum + FRAME_LIMIT/2 + 1])
    elif framenum > NUM_FRAMES - FRAME_LIMIT/2:
        frames = infiles[framenum - FRAME_LIMIT/2:]
        frames.extend(infiles[:(framenum + FRAME_LIMIT/2) % NUM_FRAMES + 1])
    else:
        frames = infiles[framenum - FRAME_LIMIT/2:framenum + FRAME_LIMIT/2 + 1]
    return frames

def main():
    """Starts 8 processes which execute frame averaging+saving tasks from a pool"""
    pool = mp.Pool(processes=8)
    for i, f in enumerate(infiles):
        frames = get_frames(i, infiles)
        pool.apply_async(make_frame, args = (frames, i))
    print "done filling pool"

    pool.close()
    pool.join()

if __name__ == '__main__':
    main()