When i build picam, i got this error.

[joelihn]

`cc stream.o hooks.o mpegts.o httplivestreaming.o state.o log.o text.o timestamp.o subtitle.o dispmanx.o -o picam -g -Wl,--whole-archive -lilclient -L/opt/vc/lib/ -L/usr/local/lib -lbrcmGLESv2 -lbrcmEGL -lopenmaxil -lbcm_host -lvcos -lvchiq_arm -lpthread -lrt -L/opt/vc/src/hello_pi/libs/ilclient -Wl,--no-whole-archive -rdynamic -lm -lcrypto -lasound `pkg-config --libs freetype2` `pkg-config --libs harfbuzz fontconfig libavformat libavcodec`
/usr/bin/ld: /usr/local/lib/libavformat.a(fifo.o): in function `fifo_init':
/home/pi/Joe/picam/ffmpeg/libavformat/fifo.c:519: undefined reference to `__atomic_store_8'
/usr/bin/ld: /usr/local/lib/libavformat.a(fifo.o): in function `fifo_write_trailer':
/home/pi/Joe/picam/ffmpeg/libavformat/fifo.c:624: undefined reference to `__atomic_fetch_add_8'
/usr/bin/ld: /home/pi/Joe/picam/ffmpeg/libavformat/fifo.c:631: undefined reference to `__atomic_store_8'
/usr/bin/ld: /usr/local/lib/libavformat.a(fifo.o): in function `fifo_thread_write_packet':
/home/pi/Joe/picam/ffmpeg/libavformat/fifo.c:188: undefined reference to `__atomic_fetch_sub_8'
/usr/bin/ld: /usr/local/lib/libavformat.a(fifo.o): in function `fifo_consumer_thread':
/home/pi/Joe/picam/ffmpeg/libavformat/fifo.c:457: undefined reference to `__atomic_load_8'
/usr/bin/ld: /usr/local/lib/libavformat.a(fifo.o): in function `fifo_write_packet':
/home/pi/Joe/picam/ffmpeg/libavformat/fifo.c:597: undefined reference to `__atomic_fetch_add_8'
collect2: error: ld returned 1 exit status
make: *** [Makefile:26：picam] 错误 1
`

[joelihn]

After add -latomic to LDFLAGS, i can build picam.

But when i run the program, it crashed.

Here is the information:

pi@raspberrypi:~/Joe/picam $ gdb --args ./picam -o /run/shm/hls --hlsenc --hlsenckeyuri enc.key   --hlsenckey f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff   --hlsenciv 000102030405060708090a0b0c0d0e0f --alsadev hw:2,0
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Reading symbols from ./picam...done.
(gdb) run
Starting program: /home/pi/Joe/picam/picam -o /run/shm/hls --hlsenc --hlsenckeyuri enc.key --hlsenckey f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff --hlsenciv 000102030405060708090a0b0c0d0e0f --alsadev hw:2,0
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1".
[New Thread 0xb61aa420 (LWP 1128)]
configuring devices
[New Thread 0xb57ff420 (LWP 1129)]
[New Thread 0xb4dff420 (LWP 1130)]
[New Thread 0xb45fe420 (LWP 1131)]
[New Thread 0xb3dfd420 (LWP 1132)]
[New Thread 0xb35fc420 (LWP 1133)]
[New Thread 0xb2dfb420 (LWP 1134)]
capturing started

Thread 8 "ILCS_HOST" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb2dfb420 (LWP 1134)]
0x000cf2e4 in hls_write_packet (hls=0x16deba8, pkt=0xb2dfab90, pkt@entry=0x0, split=<optimized out>) at httplivestreaming.c:351
351         pmt_cc = ts_st->service->pmt.cc;
(gdb) bt
#0  0x000cf2e4 in hls_write_packet (hls=0x16deba8, pkt=0xb2dfab90, pkt@entry=0x0, split=<optimized out>) at httplivestreaming.c:351
#1  0x000cc144 in send_keyframe (consume_time=<optimized out>, data_len=<optimized out>, data=0xdf70f0 <encoded_packets_size> "p\003") at stream.c:2235
#2  video_encode_fill_buffer_done (out=0x170c9f0) at stream.c:3747
#3  encode_and_send_image () at stream.c:4141
#4  cam_fill_buffer_done (data=<optimized out>, comp=<optimized out>) at stream.c:3077
#5  0x000d7104 in ilclient_fill_buffer_done (hComponent=0x16eb820, pAppData=0x16eb770, pBuffer=0x16ec460) at ilclient.c:1736
#6  0xb6f14108 in vcil_out_fill_buffer_done () from /opt/vc/lib/libopenmaxil.so
#7  0xb6f10fd8 in ilcs_command () from /opt/vc/lib/libopenmaxil.so
#8  0xb6f11e40 in ilcs_task () from /opt/vc/lib/libopenmaxil.so
#9  0xb6ececb0 in vcos_thread_entry (arg=0x16e15e8) at /home/dom/projects/staging/userland/interface/vcos/pthreads/vcos_pthreads.c:144
#10 0xb6e92494 in start_thread (arg=0xb2dfb420) at pthread_create.c:486
#11 0xb65cb578 in ?? () at ../sysdeps/unix/sysv/linux/arm/clone.S:73 from /lib/arm-linux-gnueabihf/libc.so.6
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) where
#0  0x000cf2e4 in hls_write_packet (hls=0x16deba8, pkt=0xb2dfab90, pkt@entry=0x0, split=<optimized out>) at httplivestreaming.c:351
#1  0x000cc144 in send_keyframe (consume_time=<optimized out>, data_len=<optimized out>, data=0xdf70f0 <encoded_packets_size> "p\003") at stream.c:2235
#2  video_encode_fill_buffer_done (out=0x170c9f0) at stream.c:3747
#3  encode_and_send_image () at stream.c:4141
#4  cam_fill_buffer_done (data=<optimized out>, comp=<optimized out>) at stream.c:3077
#5  0x000d7104 in ilclient_fill_buffer_done (hComponent=0x16eb820, pAppData=0x16eb770, pBuffer=0x16ec460) at ilclient.c:1736
#6  0xb6f14108 in vcil_out_fill_buffer_done () from /opt/vc/lib/libopenmaxil.so
#7  0xb6f10fd8 in ilcs_command () from /opt/vc/lib/libopenmaxil.so
#8  0xb6f11e40 in ilcs_task () from /opt/vc/lib/libopenmaxil.so
#9  0xb6ececb0 in vcos_thread_entry (arg=0x16e15e8) at /home/dom/projects/staging/userland/interface/vcos/pthreads/vcos_pthreads.c:144
#10 0xb6e92494 in start_thread (arg=0xb2dfb420) at pthread_create.c:486
#11 0xb65cb578 in ?? () at ../sysdeps/unix/sysv/linux/arm/clone.S:73 from /lib/arm-linux-gnueabihf/libc.so.6
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) 

[marler8997]

I just tried to build and got the exact same backtrace. My guess is it's a problem with the ffmpeg version I built? The docs for BUILDING.md don't specify a version and/or commit to build from. Could be a red herring but it seems like the most likely culprit at the moment. I'll try to update you if I learn more.

[marler8997]

This PR should fix the segfault: https://github.com/iizukanao/picam/pull/153

You can get around the requirement for -latomic by using ffmpeg version 4.3. We should update BUILDING.md to reflect what version of ffmpeg to pull.

[marler8997]

And this PR should clarify what version of ffmpeg to build so you don't get the undefined reference errors for missing -latomic: https://github.com/iizukanao/picam/pull/155