add optoin to use melt(MLT) to extract frames from H264

README

@@ -29,7 +29,7 @@ To run pan.do/ra you need to install and setup:
             python-geoip python-html5lib python-lxml \
             python-gst0.10 gstreamer0.10-plugins-good gstreamer0.10-plugins-bad \
             postgresql postgresql-contrib rabbitmq-server \
-            ffmpeg2theora libav-tools libavcodec-extra-53 \
+            ffmpeg2theora libav-tools libavcodec-extra-53 melt \
             python-ox oxframe imagemagick poppler-utils mkvtoolnix gpac
 
 

pandora/archive/extract.py

@@ -325,7 +325,7 @@ def run_command(cmd, timeout=10):
     return p.returncode
 
 
-def frame(video, frame, position, height=128, redo=False):
+def frame(video, frame, position, height=128, redo=False, info=None):
     '''
         params:
             video     input
@@ -339,21 +339,50 @@ def frame(video, frame, position, height=128, redo=False):
         if redo or not exists(frame):
             ox.makedirs(folder)
             if video.endswith('.mp4'):
-                cmd = [
-                    AVCONV, '-y',
-                    '-ss', str(position),
-                    '-i', video,
-                    '-an', '-vframes', '1',
-                    '-vf', 'scale=-1:%s' % height
-                ]
-                if not frame.endswith('.png'):
-                    cmd += ['-f', 'mjpeg']
-                cmd += [frame]
+                if settings.USE_MELT:
+                    cmd = melt_frame_cmd(video, frame, position, height, info)
+                else:
+                    cmd = melt_frame_cmd(video, frame, position, height)
             else:
                 cmd = ['oxframe', '-i', video, '-o', frame,
                     '-p', str(position), '-y', str(height)]
             run_command(cmd)
 
+def avconv_frame_cmd(video, frame, position, height=128):
+    cmd = [
+        AVCONV, '-y',
+        '-ss', str(position),
+        '-i', video,
+        '-an', '-vframes', '1',
+        '-vf', 'scale=-1:%s' % height
+    ]
+    if not frame.endswith('.png'):
+        cmd += ['-f', 'mjpeg']
+    cmd += [frame]
+    return cmd
+
+def melt_frame_cmd(video, frame, position, height=128, info=None):
+    if not info:
+        info = ox.avinfo(video)
+    fps = float(AspectRatio(info['video'][0]['framerate']))
+    format = frame.split('.')[-1]
+    vcodec = 'mjpeg' if format == 'jpg' else 'png'
+    cmd = [
+        'melt',
+        '-silent',
+        video,
+        'in=%d' % position, 'out=%d' % position,
+        '-consumer' 'avformat:%s' % frame,
+        'vcodec=%s' % vcodec
+    ]
+    if height:
+        dar = AspectRatio(info['video'][0]['display_aspect_ratio'])
+        width = int(dar * height)
+        width += width % 2
+        position = int(position * fps)
+        cmd += ['-s', '%sx%s' % (width, height)]
+    return cmd
+
 def frame_direct(video, target, position):
     fdir = os.path.dirname(target)
     if fdir and not os.path.exists(fdir):

pandora/item/models.py

@@ -1084,7 +1084,7 @@ class Item(models.Model):
                 path = os.path.join(settings.MEDIA_ROOT, stream.path(),
                                     'frames', "%dp"%height, "%s.jpg"%position)
                 if not os.path.exists(path) and stream.media:
-                    extract.frame(stream.media.path, path, position, height)
+                    extract.frame(stream.media.path, path, position, height, info=stream.info)
                 if not os.path.exists(path):
                     return None
                 return path

pandora/settings.py

@@ -152,6 +152,7 @@ LOGGING = {
 AUTH_PROFILE_MODULE = 'user.UserProfile'
 AUTH_CHECK_USERNAME = True
 AVCONV_VERSION = 0
+USE_MELT=False
 
 #=========================================================================
 #Pan.do/ra related settings settings

vm/firstboot.sh

@@ -52,6 +52,7 @@ apt-get install -y \
     $LIBAVCODEC_EXTRA \
     libav-tools \
     ffmpeg2theora \
+    melt \
     mkvtoolnix \
     gpac \
     imagemagick \