Reading a video file with OpenCV 2.3.1 on I.MX53

[ilo]

Hello,

I've been trying to run a simple OpenCV application which opens, reads and displays an .avi file on an IMX53 qsb

Instead of having a video frame displayed, I keep getting this warning message until the program exits:

** (fen:21270): WARNING **: ffmpegcsp0: size 729600 is not a multiple of unit size 720000

although it is just a warning the cvNamedWindow doesn't even appear.

Has anyone encountered this issue ? I believe it has something to do with the frame buffer but I have no idea how to deal with it.

NB : I use OpenCV 2.3.1 and I followed this tutorial http://technology.dip.jp/~ray/2012/12/898 to compile it for my target.

Thank you 

[andre_silva]

which bsp release are you using ? Also, OpenCV will not use our hardware to decode the videos, so, you are not going to have a good performance with this procedure. I suggest you to use gstreamer instead, the you get the video frames and then use it with opencv.

regards,

Andre

[ilo]

Thanks for your answer. I'm sorry for the long delay before my reply, I wasn't able to work on this project until now.

I'm using Linux lucid 2.6.35.3-1129-g691c08a #7 PREEMPT Wed Nov 16 14:33:06 BRST 2011 armv7l GNU/Linux.

I tried to launch the video with gstreamer to make sure the pipeline works fine before using it inside the openCV application,

gst-launch filesrc location=video.avi ! decodebin2 name=dec ! queue ! ffmpegcolorspace ! autovideosink

and this is what I get:

Setting pipeline to PAUSED ...

MFW_GST_V4LSINK_PLUGIN 2.0.3-1-179-e630aa8d build on Sep 28 2011 15:04:02.

Pipeline is PREROLLING ...

Aiur: 2.0.3-1-179-e630aa8d

Core: AVI_PARSER_03.02.00  build on Jul 11 2011 09:49:53

  mime: video/x-msvideo

  file: lib_avi_parser_arm11_elinux.3.0.so.3.2.1

Content Info:

    URI:

          file://video.avi

    Idx File:

          /home/lucid/.aiur/video.avi.aidx

    Seekable  : Yes

    Size(byte): 36107876

Movie Info:

    Seekable  : Yes

    Live      : No

    Duration  : 0:01:40.000000000

    ReadMode  : File

    Track     : 1

Track 00[Video]: Disabled

    Codec: 0, SubCodec: 0

ERROR: from element /GstPipeline:pipeline0/GstDecodeBin2:dec/GstAiurDemux:aiurdemux0: GStreamer encountered a general stream error.

Additional debug info:

aiurdemux.c(3872): aiurdemux_pull_task (): /GstPipeline:pipeline0/GstDecodeBin2:dec/GstAiurDemux:aiurdemux0:

streaming stopped, reason error, state 2

ERROR: pipeline doesn't want to preroll.

Setting pipeline to NULL ...

Total rendered:0

[--->FINALIZE aiurdemux

[--->FINALIZE v4l_sink

Freeing pipeline ...

I checked on my laptop and the gstreamer pipeline works fine. Am i missing a file or something ?

[andre_silva]

try using this pipeline:

gst-launch filesrc location=file.avi ! decodebin2 !  mfw_v4lsink      ---> for framebuffer

gst-launch filesrc location=file.avi ! decodebin2 ! ffmpegcolorspace ! mfw_v4lsink      ---> for framebuffer

gst-launch filesorc location=file.avi ! decodebin2 ! ffmpegcolorspace ! ximagesink   ---> x window

and also you can do a quick test using playbin:

gst-launch playbin uri=file:///file_path.

regards,

Andre

[ilo]

It looks like neither of them work. I keep getting the same error message.

[andre_silva]

even the playbin pipeline didnt work ?

[ilo]

even the playbin...

I will do as you say and come back if it ever get solved.

Thanks a lot for your time !

[andre_silva]

Cool, just another thing that may help you... OpenCV uses v4l libraries to create its own read/write video functions... Unless you select it to use gstreamer you don´t need gstreamer. I particularly never used OpenCV with gstreamer.

regards,

Andre

[andre_silva]

You will need to check the GST plugins you have installed, try searching for some gstreamer thread in this community. Unfortunately I´m a gstreamer expert =(