diff --git a/youtube_dl/downloader/hls.py b/youtube_dl/downloader/hls.py
index 8be4f4249..a990e5e0a 100644
--- a/youtube_dl/downloader/hls.py
+++ b/youtube_dl/downloader/hls.py
@@ -30,7 +30,7 @@ class HlsFD(FileDownloader):
 
         args = [
             encodeArgument(opt)
-            for opt in (ffpp.executable, '-y', '-i', url, '-f', 'mp4', '-c', 'copy', '-bsf:a', 'aac_adtstoasc')]
+            for opt in (ffpp.executable, '-y', '-i', url, '-f', 'mp4', '-c', 'copy', '-bsf:a', 'aac_adtstoasc', '-fflags', '+bitexact', '-flags', '+bitexact')]
         args.append(encodeFilename(tmpfilename, True))
 
         retval = subprocess.call(args)
diff --git a/youtube_dl/postprocessor/ffmpeg.py b/youtube_dl/postprocessor/ffmpeg.py
index cc65b34e7..898feed7f 100644
--- a/youtube_dl/postprocessor/ffmpeg.py
+++ b/youtube_dl/postprocessor/ffmpeg.py
@@ -131,6 +131,7 @@ class FFmpegPostProcessor(PostProcessor):
             os.stat(encodeFilename(path)).st_mtime for path in input_paths)
 
         files_cmd = []
+        opts += ['-fflags', '+bitexact', '-flags', '+bitexact']
         for path in input_paths:
             files_cmd.extend([encodeArgument('-i'), encodeFilename(path, True)])
         cmd = ([encodeFilename(self.executable, True), encodeArgument('-y')] +