mp4mux complains about missing PTS

Sebastian Dröge sebastian at
Tue Apr 18 11:45:22 UTC 2023

On Tue, 2023-04-18 at 13:42 +0200, Florian Echtler via gstreamer-devel
> I'm trying to record multiple H.264 and Opus streams to a MP4 file.
> However, 
> there is apparently some sort of race condition going on, because in
> roughly 8 
> out of 10 attempts, the pipeline fails with the following error and
> an EOS:
> gst-stream-error-quark: Could not multiplex stream. (10): 
> ../gst/isomp4/gstqtmux.c(5402): gst_qt_mux_add_buffer (): 
> /GstPipeline:pipeline0/GstBin:bin_file_sink/GstMP4Mux:mux:
> Buffer has no PTS.
> In the other 20% of cases, the pipeline starts and the resulting MP4
> file 
> contains all the streams, correctly synchronized and playable. I also
> tried with 
> qtmux instead of mp4mux, but got the same results.
> I'm attaching the dot graph for the failure case; the dot graph for a
> successful 
> run looks exactly identical, with the only difference being that the
> filesink 
> doesn't flag EOS.
> Side question: even if everything works, the resulting MP4 file is
> not seekable. 
> Is there a straightforward fix for that?

Can you create an issue with this with a way to reproduce it?
Most likely this is one of the known h264parse/baseparse PTS handling
issues though.

Sebastian Dröge, Centricular Ltd ·
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