Posts: 24
Joined: Thu Jul 30, 2020 11:43 am

problem about GStreamer on RPi4

Mon May 31, 2021 2:04 pm

some days ago I started to learn GStreamer in order to use hw codec on RPi4, I install the gst v1.14.4 from repo, and now I had below question:

- from gst-inspect tool, I guess these elements are HW decoder : v4l2h264dec/avdec_h264_mmal/omxh264dec, I build below pipeline to test these elements:
filesrc ! qtdemux ! h264parse ! v4l2h264dec/avdec_h264_mmal/omxh264dec ! videoconvert ! autovideosink
I test these elements using the pipeline, found "v4l2h264dec" make playback not smooth,"omxh264dec" make pipeline can not play,only "avdec_h264_mmal" works fine,so whether "avdec_h264_mmal" is the only hw decoder element currently?

- If I change to a file with 1080p60 h264 format,the above pipeline will not work, the playback is very stuck, why ? I remember RPi4's omx decoder can support 1080 60p H264 video;

- Which element is the HW-H265 decoder? from gst-inspect, I guess "avdec_hevc_rpi" may be the one,but when I insert the element to pipeline, the pipeline can not play, so which element is the HW-H265 decoder?

ok,above is my 3 questions, please help me,thanks!

Posts: 8
Joined: Mon May 06, 2019 2:54 pm

Re: problem about GStreamer on RPi4

Thu Jun 17, 2021 8:43 am

May I know what do you mean by 'not smooth' when using v4l2h264dec . I recently did an experiment with IP cameras and it worked for me. However I have down sampled the frame rate to suit my use case. Having said that , I did not find any issue with higher frame rate. You may please check this link to know what I did and the source code. ... -varghese/


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