advice on live capture to disk
John Bazik
john_bazik at brown.edu
Tue Sep 30 08:57:15 PDT 2014
> What version of GStreamer are you using ? What does your pipeline look
> like ? Do you get any warnings (GST_DEBUG=2) ? What are those "weavy
> artifacts" you mention ?
Here's the last one I ran yesterday:
gst-launch-1.0 -e\
decklinksrc mode=17 connection=1 name=raw\
raw.videosrc !\
queue max-size-bytes=104857600 !\
videorate ! video/x-raw,framerate=30/1 !\
videoconvert !\
avenc_huffyuv buffer-size=104857600 !\
queue max-size-bytes=104857600 ! mux.\
matroskamux name=mux !\
filesink buffer-mode=full buffer-size=104857600\
location=/var/tmp/live$$.mkv
Okay, I lied - this one works. I was dropping frames writing via NFS,
so that's my problem (unfortunately, I do need to do that).
I'd prefer to save a smaller file, though, so here's the last x264
pipeline I tried:
gst-launch-1.0 -e\
decklinksrc mode=17 connection=1 name=raw\
raw.videosrc ! queue !\
videorate ! video/x-raw,framerate=30/1 !\
videoconvert !\
x264enc speed-preset=medium ref=4 quantizer=20 !\
queue ! mux.\
raw.audiosrc ! queue ! audioconvert ! audio/x-raw,format=S16LE !\
voaacenc ! queue ! mux.\
qtmux name=mux !\
filesink location=/var/tmp/live$$.mov
My source is 720p, UYVY, 60000/1001fps. Gstreamer version is 1.2.4.
Speed-presets slower than medium drop frames. The warnings come
from decklinksrc. This looks good, but in a large white field (a
whiteboard), I see an irregular mosaic pattern emerge, grey-on-white,
and start to ripple, then it clears and starts over, continuously.
Cycles about every 8 seconds (240 frames).
That one runs at about 350% cpu (six cores). The processor is an AMD
Phenom II, running at 3.3GHz with 8G of memory.
John
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