Videos do not work when using decklinksrc mode=auto

[rinaldomerlo]

Not really needing a fix so much as wanting to bring it to your attention. I had to use the following source video pipelnie in stbt.conf on one setup where we couldn't get the usual fixed video resolutions to work:

source_pipeline = decklinkvideosrc connection=HDMI mode=auto device-number=0 ! videoconvert

With this setup everything works fine (stbt tv, test scripts, screenshots, etc) but the videos generated with --save-video are only a few bytes long and have no content.

There seems to be some initial difficulty and errors establishing the pipeline while it works out the correct resolution:

stbt-run: Arguments: control: lirc::MY_REMOTE args: ['997', '300', '100'] save_thumbnail: never verbose: 1 source_pipeline: decklinkvideosrc connection=HDMI mode=auto device-number=0 ! videoconvert save_screenshot: on-failure script: channelchange1.py restart_source: False sink_pipeline: xvimagesink sync=false save_video: test.webm stbt-run: Saving video to 'test.webm' stbt-run: sink pipeline: appsrc name=appsrc format=time is-live=true caps=video/x-raw,format=(string)BGR ! tee name=t t. ! queue leaky=downstream ! videoconvert ! vp8enc cpu-used=6 min_quantizer=32 max_quantizer=32 ! webmmux ! filesink location=test.webm t. ! queue leaky=downstream ! videoconvert ! xvimagesink sync=false stbt-run: source pipeline: decklinkvideosrc connection=HDMI mode=auto device-number=0 ! videoconvert ! queue name=_stbt_user_data_queue max-size-buffers=0 max-size-bytes=0 max-size-time=10000000000 ! decodebin ! queue name=_stbt_raw_frames_queue max-size-buffers=2 ! videoconvert ! video/x-raw,format=BGR ! identity ! appsink name=appsink max-buffers=1 drop=false sync=true emit-signals=true caps=video/x-raw,format=BGR stbt-run: LircControl: Connecting to /var/run/lirc/lircd stbt-run: LircControl: Connected to /var/run/lirc/lircd channelchange1.py: warning: gst-resource-error-quark: No signal (9): No signal gstdecklinkvideosrc.cpp(886): gst_decklink_video_src_create (): /GstPipeline:pipeline1/GstDecklinkVideoSrc:decklinkvideosrc0: No input source was detected - video frames invalid

And my guess is by the time it works itself out, the video pipeline has already been branched off.