diff --git a/panasonic.py b/panasonic.py
index 6e235a4..98dd74e 100755
--- a/panasonic.py
+++ b/panasonic.py
@@ -150,11 +150,11 @@ def dumpFilms(films):
         logger.info('%d - %s enregistré le %s sur %s. Durée: %s. %s' % (fid, film['title'], film['date'], film['channel'], film['duration'], film['url']))
         fid = fid + 1
 
-def getInitialTSFromBuffer(content):
+def getInitialTSFromBuffer(content, delta=0.1):
     logger = logging.getLogger(__name__)
 
     logger.debug('Determining initial timestamp from content')
-    with Popen(['ffprobe','/dev/stdin','-loglevel', 'quiet', '-read_intervals', '0%+0.1', '-show_entries', 'frame=frame_no,best_effort_timestamp_time', '-of','json'], stdout=PIPE, stdin=PIPE) as ffprobe:
+    with Popen(['ffprobe','/dev/stdin','-loglevel', 'quiet', '-read_intervals', ('0%%+%f' % delta), '-show_entries', 'frame=frame_no,best_effort_timestamp_time', '-of','json'], stdout=PIPE, stdin=PIPE) as ffprobe:
         out, _ = ffprobe.communicate(input=content)
         frames = json.load(BytesIO(out))
         logger.debug('Frames: %s' % frames)
@@ -257,8 +257,16 @@ def downloadMovie(url, outputFileName):
     total = timedelta(seconds=total)
     logger.debug('Header: %s' % r.headers)
 
-    initialTS = getInitialTSFromBuffer(r.content)
+    initialTS = None
+    nbRetries = 0
+    maxRetries = 10
+    while initialTS == None and nbRetries < maxRetries: 
+        initialTS = getInitialTSFromBuffer(r.content, delta=0.1*nbRetries)
+        nbRetries = nbRetries+1
     logger.debug('Initial timestamp: %s' % initialTS)
+    if initialTS == None:
+        logger.error('Impossible to retrieve initial timestamp')
+        exit(-1)
     lastTS = getLastTSFromBuffer(r.content)
     logger.debug('Last timestamp: %s' % lastTS)
     delta = lastTS-initialTS