Created method common.video.frames

Author: turian

video.py

@@ -3,28 +3,68 @@
 Grab frames from a video file.
 """
 
+import os
+import os.path
+import re
+import shutil
 import sys
 import tempfile
-from PIL import Image
+#from PIL import Image
 
-from common.misc import runcmd
+import common.misc
+from common.stats import stats
 
+#def grab_frame(filename, framenumber, FPS=29.97):
+#    """
+#    Grab a certain from an video file, and return it as a PIL Image
+#    TODO: Don't hardcode FPS.
+#    TODO: Use a better library for this.
+#    """
+#    tmp = tempfile.NamedTemporaryFile(suffix=".png")
+#    framesec = 1. * framenumber / FPS
+#    cmd = "ffmpeg -i %s -y -vcodec png -vframes 1 -an -ss %f -f rawvideo %s" % (filename, framesec, tmp.name)
+#    print >> sys.stderr, cmd
+#    runcmd(cmd)
+#    im = Image.open(tmp.name)
+#    tmp.close()
+#    return im
 
-def grab_frame(filename, framenumber, FPS=29.97):
+def frames(filename, maxframes=None):
     """
-    Grab a certain from an video file, and return it as a PIL Image
-    TODO: Don't hardcode FPS.
+    Iterate over the frames in a video file.
+    Yields (frame number, PNG filename, total frames).
+    maxframes: Maximum number of frames to return.
     TODO: Use a better library for this.
     """
-    tmp = tempfile.NamedTemporaryFile(suffix=".png")
-    framesec = 1. * framenumber / FPS
-    cmd = "ffmpeg -i %s -y -vcodec png -vframes 1 -an -ss %f -f rawvideo %s" % (filename, framesec, tmp.name)
-    print >> sys.stderr, cmd
-    runcmd(cmd)
-    im = Image.open(tmp.name)
-    tmp.close()
-    return im
+    dir = tempfile.mkdtemp()
+    inre = re.compile("in.*.jpg")
+    try:
+        # Decompose video into images
+        # I learned this command from here: http://electron.mit.edu/~gsteele/ffmpeg/
+        if maxframes is None:
+            cmd = "ffmpeg -sameq -y -r 30 -i %s %s" % (filename, os.path.join(dir, 'in%05d.jpg'))
+        else:
+            cmd = "ffmpeg -sameq -y -vframes %d -r 30 -i %s %s" % (maxframes, filename, os.path.join(dir, 'in%05d.jpg'))
+        print >> sys.stderr, "Decomposing video to images:", cmd, "\n"
+        common.misc.runcmd(cmd)
+        print >> sys.stderr, stats()
+        
+        # Find all files to process
+        infiles = []
+        for f in os.listdir(dir):
+            if inre.match(f):
+                infiles.append(f)
+        infiles.sort()
+
+        for i, f in enumerate(infiles):
+            yield i, os.path.join(dir, f), len(infiles)
+
+
+    finally:
+        print >> sys.stderr, "Removing dir %s" % dir
+        shutil.rmtree(dir)
 
 if __name__ == "__main__":
     assert len(sys.argv) == 2
     grab_image(sys.argv[1], 0)
+