PTS timestamp N/A

[joakim]

Hi,
I'm developing a c application with the following pipeline:
rtspsrc->queue->rtph264depay->h264parse->mpegtsmux->hlssink

Everything works as expected except one thing. The pts (presentation time)
value of each frame seems correct most of the time, but I get frames with a
pts value of N/A at even intervals. If I plot the values I get this graph:
<http://gstreamer-devel.966125.n4.nabble.com/file/t378727/video_from_mac.png>
(I know the y-axis is unreadable) The spikes shows when I get a frame with
N/A as pts value.

I'm wondering what could be the cause of this problem?



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[Nicolas Dufresne-5]

Le jeu. 11 avr. 2019 07 h 40, joakim <[hidden email]> a écrit :

Hi,
I'm developing a c application with the following pipeline:
rtspsrc->queue->rtph264depay->h264parse->mpegtsmux->hlssink

Everything works as expected except one thing. The pts (presentation time)
value of each frame seems correct most of the time, but I get frames with a
pts value of N/A at even intervals. If I plot the values I get this graph:
<http://gstreamer-devel.966125.n4.nabble.com/file/t378727/video_from_mac.png>
(I know the y-axis is unreadable) The spikes shows when I get a frame with
N/A as pts value.

I'm wondering what could be the cause of this problem?

Can you clarify were the frame PTS is read from ? Could also be on the player if it's read after the decoder. Be aware that historically, no timestamp means same timestamp as previous frame in GStreamer. But we try and avoid this method as much as possible.

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[joakim]

I'm using ffprobe to read the pts value of the created hls video like this:
ffprobe -show_packets <path-to-video-file> | grep 'pts='
Alright, but why would two frames have the same timestamp?



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[Nicolas Dufresne-5]

Le vendredi 12 avril 2019 à 05:02 -0500, joakim a écrit :
> I'm using ffprobe to read the pts value of the created hls video like this:
> ffprobe -show_packets <path-to-video-file> | grep 'pts='
> Alright, but why would two frames have the same timestamp?

What I said about PTS was GStreamer specific and likely don't apply to
FFMPEG. You are on your own about what these timestamp means in FFMPEG
code. There is likely a bug, but too few information to give you more
advises.

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