Run time switch video decode type(h264, jpeg) gstreamer pipeline sometime crash

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
#1

I first use gst_element_set_state NULL , then unlink eliment, make new element, link them, gst_element_set_state play.
my pipeline is appsrc->queue->h264parse/jpegparse->nvv4l2decoder.
I want to change h264 or jpeg type in runtime, but some wrong occurs sometimes, such as:

ERROR from element vdec-jpegparse: Can’t set caps to the src pad
Error details: gstjpegparse.c(836): gst_jpeg_parse_handle_frame (): /GstPipeline:media-pipeline/GstBin:vdec_subbin0/GstJpegParse:vdec-jpegparse:
Can’t set caps to the src pad

ERROR from element vdec-appsrc: Internal data stream error.
Error details: gstbasesrc.c(3055): gst_base_src_loop (): /GstPipeline:media-pipeline/GstBin:vdec_subbin3/GstAppSrc:vdec-appsrc:
streaming stopped, reason error (-5)
ERROR from element vdec-queue: Internal data stream error.
Error details: gstqueue.c(988): gst_queue_handle_sink_event (): /GstPipeline:media-pipeline/GstBin:vdec_subbin3/GstQueue:vdec-queue:
streaming stopped, reason error (-5)

#3

Hi,
We would suggest re-initialize the pipeline. Changing state to NULL and switching between H264/JPEG is not verified and may not work properly. If you would like to do further check on the case, you may download the source code of nvv4l2decoder(gst-nvvideo4linux2_src.tbz2) and rebuild with debug prints. The source code is in
https://developer.nvidia.com/embedded/l4t/r32_release_v5.1/r32_release_v5.1/sources/t186/public_sources.tbz2

#4

run time switch between h264/h265/mjpeg is request for our product application. this is convenient for user in nvr application scene. so can nvidia support this request?

recently frequently switch h264/h265/mjpeg occur segmetation fault, such as

[Thread debugging using libthread_db enabled]
Using host libthread_db library “/lib/aarch64-linux-gnu/libthread_db.so.1”.
Core was generated by `./build/apps/anfang_app/anfang_app’.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 malloc_consolidate (av=av@entry=0x7f14000020) at malloc.c:4469
4469 malloc.c: No such file or directory.
[Current thread is 1 (Thread 0x7e2cfc9830 (LWP 12179))]
(gdb) bt
#0 0x0000007f89598ac0 in malloc_consolidate (av=av@entry=0x7f14000020) at malloc.c:4469
#1 0x0000007f8959ba70 in _int_malloc (av=av@entry=0x7f14000020, bytes=bytes@entry=32816) at malloc.c:3713
#2 0x0000007f8959d3a4 in __GI___libc_malloc (bytes=32816) at malloc.c:3075
#3 0x0000007f895c3314 in __alloc_dir (fd=164, close_fd=true, flags=, statp=0x7e2cfc74b8) at …/sysdeps/posix/opendir.c:216
#4 0x0000007f895c3410 in opendir_tail (fd=164) at …/sysdeps/posix/opendir.c:136
#5 0x0000007f895debe4 in glob_in_dir (pattern=pattern@entry=0x7f50412d4d “.so", directory=directory@entry=0x7e2cfc7880 “/usr/lib/aarch64-linux-gnu/libv4l/plugins/nv”, flags=flags@entry=0, errfunc=errfunc@entry=0x0, pglob=pglob@entry=0x7e2cfc7e58, alloca_used=541920622352, alloca_used@entry=45) at …/posix/glob.c:1313
#6 0x0000007f89632390 in __glob_lstat_compat (pattern=0x7f50412d20 "/usr/lib/aarch64-linux-gnu/libv4l/plugins/nv/.so”, flags=0, errfunc=0x0, pglob=0x7e2cfc7e58)
at …/posix/glob.c:1097
#7 0x0000007f504119e8 in () at /usr/lib/aarch64-linux-gnu/tegra/libv4l2.so.0
#8 0x0000007f5040d6c0 in v4l2_fd_open () at /usr/lib/aarch64-linux-gnu/tegra/libv4l2.so.0
#9 0x0000007f5055e840 in () at /usr/lib/aarch64-linux-gnu/gstreamer-1.0/libgstnvvideo4linux2.so
#10 0x0000007f5054d494 in () at /usr/lib/aarch64-linux-gnu/gstreamer-1.0/libgstnvvideo4linux2.so
#11 0x0000007f50557178 in () at /usr/lib/aarch64-linux-gnu/gstreamer-1.0/libgstnvvideo4linux2.so
#12 0x0000007f8afa969c in () at /usr/lib/aarch64-linux-gnu/libgstvideo-1.0.so.0
#13 0x0000007f8ae94f48 in () at /usr/lib/aarch64-linux-gnu/libgstreamer-1.0.so.0
(gdb)

#5

Hi,
Currently we don’t have plan to support this usecase in default releases. Since it is open source, you can do customization and implement the usecase.

#6

base on gstreamer operator, can give some constructive suggests，crediblely finish the operater of decode type switch ? thanks