Pb with fps with mp4mux

David Ing ding at panopto.com
Tue Dec 3 16:45:59 UTC 2019

Your pipeline is basically moving h.264 packets from the udpsrc into the
mp4 file.

Unfortunately, you cannot modify the framerate by dropping some of the
h.264 packets.  You need to actually decode the video to drop frames.

You need to decode the video/x-h264 stream into video/x-raw, then re-encode
with an h.264 encoder.  Some h.264 encoders allow you to set the framerate
but some don't.  If you don't set the framerate on the encoder, you can add
some extra elements before going into the encoder.  Specifically you would
use a videoconvert element followed by a caps filter which specifies the
framerate, and then (a queue and) the h.264 encoder.

On Tue, Dec 3, 2019 at 6:34 AM Guillaume CLODIC <guillaume.clodic at ifremer.fr>

> Hi,
> i have a rtp h264 encoder with an 1080i (yes interlaced) SDI input.
> When i save the stream as a raw ts file with the following command :
>   gst-launch-1.0 -e -v udpsrc port=46234 ! filesink location=file.ts
> i then check the file with ffprobe and it says me that the fps is 25 (ok
> europe standard) and 50 tbc
> when i try to save the file as mp4 with this :
>   gst-launch-1.0 -e -v udpsrc port=46234 ! tsdemux ! video/x-h264 !
> queue ! h264parse ! mp4mux ! filesink location=file.mp4
> with ffprobe fps is 49.38 (or .60 or else) tbc is 50 and the file cannot
> be imported in professionnal movie editors such adobe premiere.
> does anyone as an idea how to obtain a mp4 file with the correct fps (ie
> 25) ?
> Regards,
> Guillaume.
> _______________________________________________
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> gstreamer-devel at lists.freedesktop.org
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