<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 TRANSITIONAL//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=UTF-8"> <META NAME="GENERATOR" CONTENT="GtkHTML/4.6.6"> </HEAD> <BODY> Le lundi 03 mars 2014 à 01:32 -0800, Ugly Face a écrit : <BLOCKQUOTE TYPE=CITE> Sorry to post another post. I do this as I have some progress in my problem. With the help of internet, I find out how to construct codec_data . In my ocasion , just copy 27 bytes from mp4 file begin after "avcC". The 27 bytes include sps (12 bytes) and pps(4 bytes) . I set the caps to appsrc and buffer that will be pushed to appsrc . However , no error occur and no more windows come up . It seems everything works correctly . Again , I find myself can not cope with it any more. </BLOCKQUOTE> It's unclear what has been done exactly. Note that PPS/SPS pair are not fixed length. If you are able to share more details about your project we could potentially give you better directions. If I understood, you have an MP4 files, though for certain reason you cannot use filesrc. If you could clarify this part that would help too. Your life could be made much simplier if you where to let GStreamer demux the mp4 file: appsrc ! qtdemux ! h264parse ! ... Nicolas </BODY> </HTML>