Such an easy question

[James]

> Utter frustration:
> 
> I have a script
> 
> #! /bin/bash
> 
> GST_DEBUG_DUMP_DOT_DIR=/home/jam/DOT gst-launch-1.0 $@ v4l2src device=/dev/video2 ! \
> 	video/x-h264,width=1920,height=1080,framerate=30/1 ! \
> 	h264parse ! \
> 	tee name=t \
> 	t. ! queue ! avdec_h264 ! xvimagesink sync=false \
> 	t. ! queue ! avdec_h264 ! xvimagesink sync=true \
> 	t. !  queue max-size-buffers=0 max-size-bytes=0 max-size-time=1000000000 ! \
> 	mux. pulsesrc device=0 ! \
> 	queue ! \
> 	audioconvert ! \
> 	audioresample ! audio/x-raw, rate=16000 ! \
> 	queue ! \
> 	avenc_aac ! \
> 	queue ! \
> 	mux. mp4mux name=mux ! \
> 	filesink location=try9.mp4
> 
> and a C version that behaves pretty much identically.
> 
> Running the script on its own I have never seen it fail.
> My app is a QT5 gui. Running my app AND the script OR the compiled version by QProcess sometimes fails with the dreaded pulsesrc underflow, downstream consuming too slowly message.
> If it fails, it always fails until reboot.
> 
> htop shows cpu usage of 10..30% 5..6G ram as cache and 0 swap being used.
> gnome-system-monitor shows no spikes in cpu usage.
> In desperation I swapped my 2 core i3 for a 4 core i7. Behaviour was the same.
> 
> At other times it works for hours, many times in a row.
> 
> What measurements might I make that may lead me to the problem.
> 
> Needless to say if I leave the tee multiplex (and hence pulsesrc) out of the pipline then it never fails.
> I've tried mp4mux, qtmux and (by accident) mpegtsmux without any change being visible. I tried matuska but that fails everytime.
> 
> This gets more outlandish:
> App->record: error after 25sec
> App->quit
> Script->record: all ok
> App->start
> Script stop
> App->record: all ok
> Repeatable, tried lots of times !!!
> Note
> App->record: error
> App->idle
> Script->record: error every time.
> cpu usage never goes over 40%

On the chance someone recognises detail I post. This is playing a *bad* file:

VLC error list

[00007fd5accd5840] main decoder error: Could not convert timestamp 2456057878 for FFmpeg
[00007fd5accd5840] main decoder error: Timestamp conversion failed (delay 1000000, buffering 100000, bound 9000000)
[00007fd5accd5840] main decoder error: Could not convert timestamp 2456093211 for FFmpeg

MPlayer error list

libavformat file format detected.
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fa17f53b7a0]Protocol name not provided, cannot determine if input is local or a network protocol, buffers and access patterns cannot be configured optimally without knowing the protocol
[lavf] stream 0: video (h264), -vid 0
==========================================================================
AO: [pulse] 16000Hz 2ch floatle (4 bytes per sample)
Starting playback...
Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.

Possibly bad interleaving detected.
Use -ni option if this causes playback issues and avoid or fix the program that created the file.
A: 153.6 V: 163.6 A-V: -9.965 ct: -0.587   0/  0 53%  1%  0.2% 0 0

Still trying to find out what happens when the system is in *bad* mode vs *good* mode
James
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/gstreamer-devel/attachments/20210816/09cc12f3/attachment.htm>