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opencv / opencv

Open Source Computer Vision Library
https://opencv.org
Apache License 2.0
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CV_CAP_GSTREAMER_QUEUE_LENGTH fails #8601

Open eruffaldi opened 7 years ago

eruffaldi commented 7 years ago

I have a scenario in which I am processing an mp4 file in batch mode using VideoCapture via gstreamer. In this case appsink requires the sync=false property so that the execution is at fastest speed without delays.

The problem is that the appsink is configured by cap_gstreamer.cpp as drop with buffer 1. Using the property CV_CAP_GSTREAMER_QUEUE_LENGTH to modify the buffering makes the pipeline crash probably because it is not

Example (OSX with OpenCV 3.2.0) with the following input

filesrc location=x.mp4 ! qtdemux ! h264parse ! vtdec_hw ! videoconvert ! appsink sync=false

Performance motivato: the same FULL HD video playbacks in 100-200 us using gstreamer and in 3-4ms using the hardware decoding provided by OSX VideoToolbox and made accessible by gstreamer via vtdec_hw.

The specific error is with qtdemux.

jjylonen commented 7 years ago

Same problem, but with matroskademux