import json, re, subprocess, urllib2
def get_fps_given_nframes(url, nframes):
try:
out = subprocess.check_output(['ffprobe', '-i', url, '-show_frames', '-read_intervals', '%+#' + str(nframes), '-select_streams', 'v'], stderr=subprocess.STDOUT)
except subprocess.CalledProcessError:
return None
frametimes = [float(match.group(1)) for match in re.finditer(r'pts_time=([\d\.]+)', out)]
# frametimes contain the beginning timestamps of each frame
# len(frametimes) - 1 is the numerator below due to fencepost:
fps = (len(frametimes) - 1) / (max(frametimes) - min(frametimes))
return fps
def print_fps_stats(root_url):
r = json.loads(urllib2.urlopen(root_url + '/r.json').read())
nframes = int(r['frames']) + int(r['leader'])
advertised_fps = float(r['fps'])
print '%s:' % root_url
for video in ['/0/0/0.mp4', '/0/0/0.webm']:
url = root_url + video
actual_fps = get_fps_given_nframes(url, nframes)
if actual_fps != None:
print (' %s: %d frames, advertised %.4f, actual %.4f, adv/act = %.2f%%' %
(video, nframes, advertised_fps, actual_fps, advertised_fps / actual_fps * 100.0))
else:
print ' %s: not found' % video
FPS are right on the money for both mp4 and webm
print_fps_stats('https://earthengine.google.org/timelapse/data/20130507/1068x600')
print_fps_stats('http://commondatastorage.googleapis.com/earthengine-timelapse/seasonal-20140202/1068x600')
https://earthengine.google.org/timelapse/data/20130507/1068x600: /0/0/0.mp4: 29 frames, advertised 10.0000, actual 10.0000, adv/act = 100.00% /0/0/0.webm: 29 frames, advertised 10.0000, actual 10.0000, adv/act = 100.00% http://commondatastorage.googleapis.com/earthengine-timelapse/seasonal-20140202/1068x600: /0/0/0.mp4: 634 frames, advertised 12.0000, actual 12.0000, adv/act = 100.00% /0/0/0.webm: 634 frames, advertised 12.0000, actual 12.0002, adv/act = 100.00%
Almost all the FPS are 100% accurate for both mp4 and webm. The one exception is Blue Marble, which is 99.98%, but since it's only 12 frames long, such a tiny error only results in a .0024 frame error by the end. (Perhaps it's a lack of precision in reading the frame time, in which case the % error would naturally go down in the longer videos).
An aside: some of the appended black trailers for .mp4 appear to be have a different FPS from the main video, so print_fps_stats compensates by only looking at the frames before the trailer.
print_fps_stats('http://g7.gigapan.org/timemachines/brassica-15m-g10-bf0-l/brassica-15m-g10-bf0-l-1088x624')
print_fps_stats('http://g7.gigapan.org/timemachines/e5-crf28-g10-bf0-l/e5-crf28-g10-bf0-l90-25fps-1088x624')
print_fps_stats('http://g7.gigapan.org/timemachines/blue-marble-v2/blue-marble-v2-crf28-6fps-1088x624')
print_fps_stats('http://g7.gigapan.org/timemachines/pittsburgh-v12/crf26-12fps-l70-1088x624')
http://g7.gigapan.org/timemachines/brassica-15m-g10-bf0-l/brassica-15m-g10-bf0-l-1088x624: /0/0/0.mp4: 3130 frames, advertised 25.0000, actual 25.0000, adv/act = 100.00% /0/0/0.webm: 3130 frames, advertised 25.0000, actual 25.0000, adv/act = 100.00% http://g7.gigapan.org/timemachines/e5-crf28-g10-bf0-l/e5-crf28-g10-bf0-l90-25fps-1088x624: /0/0/0.mp4: 1457 frames, advertised 25.0000, actual 25.0000, adv/act = 100.00% /0/0/0.webm: 1457 frames, advertised 25.0000, actual 25.0000, adv/act = 100.00% http://g7.gigapan.org/timemachines/blue-marble-v2/blue-marble-v2-crf28-6fps-1088x624: /0/0/0.mp4: 12 frames, advertised 6.0000, actual 6.0000, adv/act = 100.00% /0/0/0.webm: 12 frames, advertised 6.0000, actual 6.0011, adv/act = 99.98% http://g7.gigapan.org/timemachines/pittsburgh-v12/crf26-12fps-l70-1088x624: /0/0/0.mp4: 15271 frames, advertised 12.0000, actual 12.0000, adv/act = 100.00% /0/0/0.webm: 15271 frames, advertised 12.0000, actual 12.0000, adv/act = 100.00%
Looks like the transition from spot-on to 100.08% happens on March 10, which appears to be the same day the URL pattern for the root directory changes. 100.08% * 1440 frames ~= 1489.2, so the error is definitely enough to give us errors seeking.
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-02-17.timemachine/crf26-12fps-l70-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-01.timemachine/crf26-12fps-l70-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-04.timemachine/crf26-12fps-l70-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-07.timemachine/crf26-12fps-l70-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-08.timemachine/crf26-12fps-l70-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-09.timemachine/crf26-12fps-l70-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-10.timemachine/crf26-12fps-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-11.timemachine/crf26-12fps-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-12.timemachine/crf26-12fps-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-15.timemachine/crf26-12fps-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-20.timemachine/crf26-12fps-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-04-01.timemachine/crf26-12fps-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-05-01.timemachine/crf26-12fps-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-06-01.timemachine/crf26-12fps-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-07-01.timemachine/crf26-12fps-1424x800')
print_fps_stats('http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-08-01.timemachine/crf26-12fps-1424x800')
http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-02-17.timemachine/crf26-12fps-l70-1424x800: /0/0/0.mp4: 1510 frames, advertised 12.0000, actual 12.0000, adv/act = 100.00% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-01.timemachine/crf26-12fps-l70-1424x800: /0/0/0.mp4: 1488 frames, advertised 12.0000, actual 12.0000, adv/act = 100.00% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-04.timemachine/crf26-12fps-l70-1424x800: /0/0/0.mp4: 1506 frames, advertised 12.0000, actual 12.0000, adv/act = 100.00% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-07.timemachine/crf26-12fps-l70-1424x800: /0/0/0.mp4: 1510 frames, advertised 12.0000, actual 12.0000, adv/act = 100.00% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-08.timemachine/crf26-12fps-l70-1424x800: /0/0/0.mp4: 1506 frames, advertised 12.0000, actual 12.0000, adv/act = 100.00% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-09.timemachine/crf26-12fps-l70-1424x800: /0/0/0.mp4: 1450 frames, advertised 12.0000, actual 12.0000, adv/act = 100.00% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-10.timemachine/crf26-12fps-1424x800: /0/0/0.mp4: 1388 frames, advertised 12.0000, actual 11.9910, adv/act = 100.08% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-11.timemachine/crf26-12fps-1424x800: /0/0/0.mp4: 1488 frames, advertised 12.0000, actual 11.9909, adv/act = 100.08% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-12.timemachine/crf26-12fps-1424x800: /0/0/0.mp4: 1494 frames, advertised 12.0000, actual 11.9910, adv/act = 100.08% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-15.timemachine/crf26-12fps-1424x800: /0/0/0.mp4: 1498 frames, advertised 12.0000, actual 11.9909, adv/act = 100.08% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-03-20.timemachine/crf26-12fps-1424x800: /0/0/0.mp4: 1508 frames, advertised 12.0000, actual 11.9909, adv/act = 100.08% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-04-01.timemachine/crf26-12fps-1424x800: /0/0/0.mp4: 1468 frames, advertised 12.0000, actual 11.9909, adv/act = 100.08% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-05-01.timemachine/crf26-12fps-1424x800: /0/0/0.mp4: 1508 frames, advertised 12.0000, actual 11.9909, adv/act = 100.08% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-06-01.timemachine/crf26-12fps-1424x800: /0/0/0.mp4: 1508 frames, advertised 12.0000, actual 11.9909, adv/act = 100.08% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-07-01.timemachine/crf26-12fps-1424x800: /0/0/0.mp4: 875 frames, advertised 12.0000, actual 11.9913, adv/act = 100.07% /0/0/0.webm: not found http://timemachine1.gc.cs.cmu.edu/timemachines/breathecam/timemachines/heinz/2014-08-01.timemachine/crf26-12fps-1424x800: /0/0/0.mp4: 1078 frames, advertised 12.0000, actual 11.9911, adv/act = 100.07% /0/0/0.webm: not found
def get_fps_nframes(url):
try:
out = subprocess.check_output(['ffprobe', '-i', url, '-show_frames', '-select_streams', 'v'], stderr=subprocess.STDOUT)
except subprocess.CalledProcessError:
return (None, None)
nframes = len(list(re.finditer(r'\[FRAME\]', out)))
components = re.search(r'Duration: ([\:\.\d]+)', out).group(1).split(':')
if len(components) != 3:
raise("Unrecognized format for duration")
duration = 3600 * float(components[0]) + 60 * float(components[1]) + float(components[2])
print 'duration=%g' % duration
return (nframes / duration, nframes)