GNOME Bugzilla – Bug 752523
avdec_h264 crashes when using debug-mv=true option
Last modified: 2016-04-08 16:40:41 UTC
FFmpeg/Libav can display motion vectors on top of h264 decoded video. The avdec_h264 element has a property: - 'debug-mv': Whether libav should print motion vectors on top of the image Enabling this option crashes a pipeline. When looking at how it's done in FFmpeg, it happens in the mpegvideo.c file in the function ff_print_debug_info(), which wraps ff_print_debug_info2(), and there the motion vectors are drawn. In the gst-libav version of mpegvideo.c, ff_print_debug_info() doesn't do anything except logging. ff_print_debug_info2() is absent.
When using the latest gst-libav plugins with the switch to ffmpeg, the ff_print_debug_info2() and associated drawing functions are available again. However, still crashes. The problem is 'solved' by commenting out the line 2178: "pict->opaque=NULL;" in that function (in the mpegvideo.c file). I don't know what this has for consequences, and that line is there in the ffmpeg 2.7.2 distribution as well, working without any problems out of the box displaying MV.
Can you start a discussion with upstream FFMPeg please.
Any news here?
I used this during an internship where I ran into this problem. I've made some customizations which did work, but I am not allowed to disclose the code.
You might want to point wherever you did that internship to the terms of the LGPL license then. It's still crashing with the latest version, but this looks like a ffmpeg problem overall.
(In reply to Mathieu Hinderyckx from comment #4) > I used this during an internship where I ran into this problem. I've made > some customizations which did work, but I am not allowed to disclose the > code. Also, note that you (and your university) are not allowed to distribute this work without disclosing the changes.
For what it's worth, still happening in 1.8