Null pointer reference in GPAC at src/filter_core/filter_pid.c:5394

[AntsKnows]

Thanks for reporting your issue. Please make sure these boxes are checked before submitting your issue - thank you!

• I looked for a similar issue and couldn't find any.
• I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/
• I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line ...)

Step to reproduce:

1.get latest commit code (GPAC version 1.1.0-DEV-rev1170-g592ba2689-master)
2.compile with --enable-sanitizer
3.run  ./gpac nhmlr:reframe=1:gpac:index=1.0:gpac:src=

Im not sure if it's a correct usage of "nhmlr filter" , or by which way could i parse nhml file?

Env:
Ubunut 20.04 , clang 12.0.1

ASAN report

==2311904==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7fa16d0fb321 bp 0x7fff730acdb0 sp 0x7fff730acc20 T0)
==2311904==The signal is caused by a READ memory access.
==2311904==Hint: address points to the zero page.
    #0 0x7fa16d0fb321 in gf_filter_pid_get_packet /home/lly/pro/gpac_public/src/filter_core/filter_pid.c:5394:6
    #1 0x7fa16d22468a in nhmldmx_process /home/lly/pro/gpac_public/src/filters/dmx_nhml.c:1320:8
    #2 0x7fa16d15a431 in gf_filter_process_task /home/lly/pro/gpac_public/src/filter_core/filter.c:2441:7
    #3 0x7fa16d13d2a7 in gf_fs_thread_proc /home/lly/pro/gpac_public/src/filter_core/filter_session.c:1640:3
    #4 0x7fa16d13c850 in gf_fs_run /home/lly/pro/gpac_public/src/filter_core/filter_session.c:1877:2
    #5 0x4d12ed in gpac_main /home/lly/pro/gpac_public/applications/gpac/main.c:2254:7
    #6 0x7fa16c0210b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
    #7 0x41fe0d in _start (/home/lly/pro/gpac_public/bin/gcc/gpac+0x41fe0d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /home/lly/pro/gpac_public/src/filter_core/filter_pid.c:5394:6 in gf_filter_pid_get_packet

[jeanlf]

Thanks for the report, we had a bug triggering filter process on non source filters when "src" was set.
The proper way to use the filter for your case is simply
gpac -i file.nhml:reframe=1 ...

[AntsKnows]

Thanks for the report, we had a bug triggering filter process on non source filters when "src" was set.
The proper way to use the filter for your case is simply
gpac -i file.nhml:reframe=1 ...

Hello @jeanlf,
I've tried your suggestion, but failed with a message

"No filter chain found for PID test.nhml in filter fin to any loaded filters - NOT CONNECTED"
"Argument ":reframe" was set but not used by any filter"

And i tried
gpac -i test.nhml nhmlr:reframe=1:gpac:index=1.0 -o /dev/null
got:

"No filter chain found for PID test_export.nhml in filter nhmlr to any loaded filters - NOT CONNECTED"

My purpose is touching the code in function nhmldmx_send_sample() at src/filters/dmx_nhml.c:929, could u please help me the right command line?

[jeanlf]

if you try:
gpac -i test.nhml:reframe=1:index=1.0 inspect:deep
you should see the content of your nhml file

Using either of the following

gpac -i test.nhml:reframe=1:index=1.0 -o /dev/null
gpac -i test.nhml nhmlr:reframe=1:gpac:index=1.0 -o /dev/null

simply forward fin (raw file) to /dev/null because no extension/format is provided on the output, hence the message. You can check this adding -graph to your command line.

If you use:

gpac -i test.nhml:reframe=1:index=1.0 -o /dev/null:ext=mp4
gpac -i test.nhml nhmlr:reframe=1:gpac:index=1.0 -o /dev/null:ext=mp4

then a mp4 muxer will be loaded.

Otherwise you will need to force fout to only use inputs from nhmlr using link directives (here, '@'):

gpac -i test.nhml nhmlr:reframe=1 @ -o /dev/null:ext=mp4

[AntsKnows]

Truly appreciate it, i've tried commands above.It does work!