H264 NAL Unit Not Found Error

Nicolas Dufresne nicolas at ndufresne.ca
Tue Nov 6 13:02:19 UTC 2018

Le mardi 06 novembre 2018 à 00:38 -0600, unalozten a écrit :
> frame.pcap
> <http://gstreamer-devel.966125.n4.nabble.com/file/t378626/frame.pcap>  

The pcap does not include any pps/sps, as a side effect, the
depayloader drops the stream as it can't create caps for it. Can you
provide an sprop of a pcap with sps/pps packet ?

> Hello,
> We've using gstreamer to play and record h264 live video stream, but
> recently we've encountered a problem during one of the tests.
> The problem is that h264parse element sent an error message says that “H264
> NAL Unit not found”. When we investigated the problem, we saw that in one of
> the frames, consecutive bytes of 00s followed by 01 was taken as a new
> frame.

You mean a new NALU. This would be strictly forbidden by the H264 spec,
and pretty hard to workaround. Though, I'd like to check the bitstream
myself before jumping to conclusions.

> However, in h264 protocol, it’s stated that in order to distinguish
> consecutive 00s in the data from the start of the frame, third byte of 00s
> should be changed with 03, we’re aware that this is a problem with encoding
> the raw video.
> However we were wondering if there is a way to go around this problem on the
> gstreamer side.
> You can find the related wireshark capture of the erroneous frame in the
> attachment.
> Thank you in advance for your reply.
> Sincerely,
> Unal
> --
> Sent from: http://gstreamer-devel.966125.n4.nabble.com/
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