how to reduce gstreamer streaming latency

[swl]

Hi,

I am experiencing slow decoding and low streaming quality when trying to stream out video from i.mx6 quad core. I am wondering if I matched the pipeline wrongly.

The following the is pipeline i used

(receiver on desktop connected via ethernet to i.mx6)

1.gst-launch udpsrc caps=" application/x-rtp,media=(string)video,clock-rate=(int)90000,encoding-name=(string)H264,payload=(int)96,ssrc=(uint)2674837201,clock-base=(uint)2959668548,seqnum-base=(uint)14300" port=5000 ! rtph264depay ! decodebin2 ! d3dvideosink

(sender from i.mx6)

//sending using test pattern

1.) gst-launch videotestsrc ! x264enc ! rtph264pay ! udpsink host=192.168.0.100 port=5000 -v

//sending using filesrc with a sample video file

2.) gst-launch filesrc location=Trailer.mp4 ! decodebin2 ! x264enc ! rtph264pay ! udpsink host=192.168.0.100 port=5000

3.) gst-launch filesrc location=Trailer.mp4 ! decodebin2 ! vpuenc codec=6 ! queue ! rtph264pay ! udpsink host=192.168.0.100 port=5000

I attached the log from the receiver end

(1.)log_videotestsrc.txt

(2.)log_filesrc.txt

(3.)log_filesrc_vpuenc.txt

The following is one of the common message i see at the receiver end:

WARNING: from element /GstPipeline:pipeline0/GstD3DVideoSink:d3dvideosink0: A lot of buffers are being dropped.

Additional debug info:

gstbasesink.c(2873): gst_base_sink_is_too_late (): /GstPipeline:pipeline0/GstD3DVideoSink:d3dvideosink0:

There may be a timestamping problem, or this computer is too slow.

At Receiver end:

1.) the test pattern is not stable throughout, it seems to be dropping packets

2.) the sample video take a long time to start decode and did not manage to complete. ( stop right after few seconds of display w/distortion)

3.) the sample video managed to decode with distortion and delay.

I am wondering what would be a better pipeline to use to reduce the latency.

I recently also start using libmfw_gst_tvsrc.so to grab the tvin source, I would like to find out how can the raw video be scaled as I did not see the caps options for tvsrc, I tried gst-launch tvsrc ! video/x-raw-yuv, width=720, height=480 ! mfw_ipucsc ! video/x-raw-yuv, width=360, height=240 ! vpuenc codec=6 ! queue ! rtph264pay ! udpsink host=192.168.0.100 port=5000 but did not work.

Thanks and Regards,

Eric

Original Attachment has been moved to: log_videotestsrc.txt.zip

Original Attachment has been moved to: log_filesrc.txt.zip

Original Attachment has been moved to: log_filesrc_vpuenc.txt.zip

[RobbieJiang]

Try tvsrc with 720x576.

[swl]

Hi Robbie,

The camera I am using is NTSC not PAL but thanks for the suggestion anyway. :smileyhappy:

[RobbieJiang]

Hi swl,

My experience is that tvsrc can only  work with a resolution equal to the standard size of NTSC/PAL.

You can check the standard size of NTSC/PAL in mxc_v4l2_capture.c.

[shengqiangai]

Can you give me a sample that  how to use tvsrc  (gstreamer element ) to streaming a video on the network

[RobbieJiang]

Plz refer my post at:

https://community.freescale.com/message/495202#495202

[shengqiangai]

How could you get the mfw_deinterlacer element, i don't have it?

And if i use the follow cmd:

gst-launch -v tvsrc device=/dev/video0 ! 'video/x-raw-yuv,format=(fourcc)UYVY,width=720,height=576,framerate=15/1' ! mfw_ipucsc ! 'video/x-raw-yuv,format=(fourcc)I420, width=320,height=240,framerate=15/1'! vpuenc codec=avc gopsize=2 ! video/x-h264,width=320,height=240 ! rtph264pay ! udpsink host=192.168.1.108 port=5000

I get the follow err info:

WARNING: erroneous pipeline: could not link mfwgsttvsrc0 to mfwgstipucsc0

[swl]

Hi Robbie,

Thanks again for the hint, but I was wondering if it is possible to do scaling of the raw video with tvsrc in an attempt to reduce the resolution before encoding the video.

Regards,

[jamesbone]

Hi  swl,

The only place where you can do the scaling is in the  IPU,  so in order to do the change scaling before the scaling you need to start a task something like

this:

gst-launch v4l2src ! video/x-raw-yuv,width=320,height=240 ! mfw_isink disp-width=240 disp-height=120 axis-left=1200 axis-top=500 rotation=3