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20 hours ago •
mltframework
mltframework
Pressing and holding Enter-key in playlist on a single mp4 test video seems to generate memory leak
I've tested holding the Enter key (for at least 30-60 seconds) on a single file in the playlist. It seems like its leaking some memory (RES is now on 3,1g). Maybe this can lead to problems when navigating the playlist during editing.
Shotcut-version : 18.11.18.02 (disabled GPU effects) Fedora: 29
top -p $(pgrep shotcut)
`Threads: 33 total, 0 running, 33 sleeping, 0 stopped, 0 zombie
%Cpu(s): 4,4 us, 1,9 sy, 0,0 ni, 91,9 id, 1,3 wa, 0,4 hi, 0,2 si, 0,0 st
GiB Mem : 5,7 total, 0,5 free, 4,2 used, 1,1 buff/cache
GiB Swap: 5,6 total, 2,7 free, 2,9 used. 0,6 avail Mem
USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P PPID nTH PID COMMAND
henning 5 -15 6565,7m 3,1g 43,5m S 0,8 53,6 0:06.52 2 5908 33 28652 SDLAudioP2
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 5:12.28 1 5908 33 28545 shotcut
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.00 3 5908 33 28546 shotcut
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:01.48 2 5908 33 28547 QXcbEventReader
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.00 0 5908 33 28552 gmain
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.00 0 5908 33 28554 gdbus
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.00 2 5908 33 28555 dconf worker
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.05 1 5908 33 28556 QDBusConnection
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.00 2 5908 33 28558 shotcut:disk$0
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.09 3 5908 33 28559 Qt bearer threa
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.04 3 5908 33 28560 Database
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.08 3 5908 33 28561 QQmlThread
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.00 3 5908 33 28562 shotcut
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.00 3 5908 33 28565 QNetworkAccessM
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:02.30 1 5908 33 28640 FrameRenderer
henning 39 19 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.00 0 5908 33 28641 PulseHotplug
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.89 0 5908 33 28642 shotcut
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 1:03.04 2 5908 33 28643 Mlt::RenderThre
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:10.64 2 5908 33 28644 Mlt::RenderThre
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:10.51 0 5908 33 28645 Mlt::RenderThre
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:10.84 1 5908 33 28646 Mlt::RenderThre
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:10.44 1 5908 33 28647 Mlt::RenderThre
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.22 0 5908 33 28654 shotcut
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.04 0 5908 33 25939 shotcut
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.06 2 5908 33 25940 shotcut
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.02 0 5908 33 25941 shotcut
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.02 0 5908 33 25942 shotcut
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.02 0 5908 33 25943 shotcut
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.04 2 5908 33 25944 Mlt::RenderThre
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.05 3 5908 33 25945 Mlt::RenderThre
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.04 3 5908 33 25946 Mlt::RenderThre
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.01 3 5908 33 25947 Mlt::RenderThre
henning 20 0 6565,7m 3,1g 43,5m S 0,0 53,6 0:00.02 3 5908 33 25948 Mlt::RenderThre `
`
henning@satellite Shotcut]$ tail ~/.local/share/Meltytech/Shotcut/shotcut-log.txt
[Debug ] <MLT> [producer avformat-novalidate] "/home/henning/Nedlastinger/test.mp4" checking VFR: pkt.duration 512
[Debug ] <MLT> [producer avformat-novalidate] "/home/henning/Nedlastinger/test.mp4" checking VFR: pkt.duration 512
[Debug ] <MLT> [producer avformat-novalidate] "/home/henning/Nedlastinger/test.mp4" checking VFR: pkt.duration 512
[Debug ] <MLT> [producer avformat-novalidate] "/home/henning/Nedlastinger/test.mp4" checking VFR: pkt.duration 512
[Debug ] <MLT> [producer avformat-novalidate] "/home/henning/Nedlastinger/test.mp4" checking VFR: pkt.duration 512
[Debug ] <MLT> [producer avformat-novalidate] "/home/henning/Nedlastinger/test.mp4" checking VFR: pkt.duration 512
[Debug ] <MLT> [producer avformat-novalidate] "/home/henning/Nedlastinger/test.mp4" checking VFR: pkt.duration 512
[Debug ] <MLT> [producer avformat-novalidate] "/home/henning/Nedlastinger/test.mp4" checking VFR: pkt.duration 512
[Debug ] <MLT> [producer avformat-novalidate] "/home/henning/Nedlastinger/test.mp4" checking VFR: pkt.duration 512
[Debug ] <MLT> [producer avformat-novalidate] "/home/henning/Nedlastinger/test.mp4" checking VFR: pkt.duration 512
`
[henning@satellite ~]$ lsof -p $(pgrep shotcut) | tail
shotcut 28545 henning 112r REG 253,2 1471917 1967667 /home/henning/Nedlastinger/test.mp4
shotcut 28545 henning 113r REG 253,2 1471917 1967667 /home/henning/Nedlastinger/test.mp4
shotcut 28545 henning 114r REG 253,2 1471917 1967667 /home/henning/Nedlastinger/test.mp4
shotcut 28545 henning 115r REG 253,2 1471917 1967667 /home/henning/Nedlastinger/test.mp4
shotcut 28545 henning 116r REG 253,2 1471917 1967667 /home/henning/Nedlastinger/test.mp4
shotcut 28545 henning 117r REG 253,2 1471917 1967667 /home/henning/Nedlastinger/test.mp4
shotcut 28545 henning 118r REG 253,2 1471917 1967667 /home/henning/Nedlastinger/test.mp4
shotcut 28545 henning 119r REG 253,2 1471917 1967667 /home/henning/Nedlastinger/test.mp4
shotcut 28545 henning 263r REG 253,2 1471917 1967667 /home/henning/Nedlastinger/test.mp4
shotcut 28545 henning 264r REG 253,2 1471917 1967667 /home/henning/Nedlastinger/test.mp4
Shotcut-version : 18.11.18.02 (disabled GPU effects) Fedora: 29
This is not a build created and supported by us. I do not know the version of MLT used in this, and that might be a factor as I did not reproduce this on macOS. I will try on Linux next using one of our builds.
I only experienced something extremely minor on Linux using my build with MLT 6.12.0, RES: 271366 -> 310308 when holding Enter for 2 minutes.
I've also tested with flatpak build now. Current top info: RES 2,5g and VIRT 7739,2m
Tracing memory access when pressing Enter on test-file in playlist:
I see mmap of 8392704 bytes at 0x7f7026fe0000 and then later madvise DONTNEED of 8368128 bytes. I cannot see any release of the mmap for 0x7f7027fe2000 memory.
5 shotcut cloned threads (25784-25788) and 1 'Thread (pooled)' 25789
`[pid 4413] munmap(0x7f7027fe2000, 8392704) = 0
strace: Process 25784 attached
strace: Process 25785 attached
strace: Process 25786 attached
strace: Process 25787 attached
[pid 4413] mmap(NULL, 8392704, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_STACK, -1, 0) = 0x7f7027fe2000
[pid 4413] mprotect(0x7f7027fe2000, 4096, PROT_NONE) = 0
strace: Process 25788 attached
[pid 4413] mmap(NULL, 8392704, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_STACK, -1, 0) = 0x7f7026fe0000
[pid 4413] mprotect(0x7f7026fe0000, 4096, PROT_NONE) = 0
strace: Process 25789 attached
[pid 4413] munmap(0x7f704c092000, 16384) = 0
[pid 4413] munmap(0x7f703a827000, 12288) = 0
[pid 4413] munmap(0x7f7044008000, 16384) = 0
[pid 4413] munmap(0x7f704c092000, 16384) = 0
[pid 25789] madvise(0x7f7026fe0000, 8368128, MADV_DONTNEED) = 0
[pid 25789] +++ exited with 0 +++
[pid 4413] munmap(0x7f7054001000, 16384) = 0
`
Tracing file access: It seems like duplicate stats are run, two open calls for mp4 file ?
strace -e trace=file -f -p $(pgrep shotcut)
`[pid 4413] getcwd("/home/henning", 4096) = 14
[pid 24013] +++ exited with 0 +++
[pid 24014] +++ exited with 0 +++
[pid 24015] +++ exited with 0 +++
[pid 24016] +++ exited with 0 +++
[pid 24017] +++ exited with 0 +++
[pid 4413] open("/home/henning/Nedlastinger/test.mp4", O_RDONLY) = 26
[pid 4413] open("/home/henning/Nedlastinger/test.mp4", O_RDONLY) = 35
[pid 4413] open("/sys/devices/system/cpu/online", O_RDONLY|O_CLOEXEC) = 26
strace: Process 24060 attached
strace: Process 24061 attached
strace: Process 24062 attached
strace: Process 24063 attached
strace: Process 24064 attached
[pid 24018] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2251, ...}) = 0
[pid 24018] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2251, ...}) = 0
[pid 24018] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2251, ...}) = 0
[pid 4413] stat("/home/henning/.var/app/org.shotcut.Shotcut/data/Meltytech/Shotcut", {st_mode=S_IFDIR|0775, st_size=4096, ...}) = 0
[pid 4413] stat(":/icons/oxygen/32x32/actions/player-volume.png", 0x7ffea1309300) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/home/henning/.var/app/org.shotcut.Shotcut/data/mime", 0x7ffea1308f60) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/app/share/mime", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/usr/share/mime", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/usr/share/runtime/share/mime", 0x7ffea1308f60) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/run/host/share/mime", 0x7ffea1308f60) = -1 ENOENT (No such file or directory)
[pid 4413] access("/app/share/mime/packages/freedesktop.org.xml", F_OK) = -1 ENOENT (No such file or directory)
[pid 4413] access("/usr/share/mime/packages/freedesktop.org.xml", F_OK) = 0
[pid 4413] open("/app/share/mime/packages", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 26
[pid 4413] stat("/usr/share/mime/mime.cache", {st_mode=S_IFREG|0644, st_size=133224, ...}) = 0
[pid 4413] stat("/home/henning/.var/app/org.shotcut.Shotcut/data/mime/image/png.xml", 0x7ffea1308ff0) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/app/share/mime/image/png.xml", 0x7ffea1308ff0) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/usr/share/mime/image/png.xml", {st_mode=S_IFREG|0644, st_size=2683, ...}) = 0
[pid 4413] stat("/usr/share/runtime/share/mime/image/png.xml", 0x7ffea1308ff0) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/run/host/share/mime/image/png.xml", 0x7ffea1308ff0) = -1 ENOENT (No such file or directory)
[pid 4413] open("/usr/share/mime/image/png.xml", O_RDONLY|O_CLOEXEC) = 26
[pid 4413] stat(":/icons/oxygen/32x32/status/audio-volume-muted.png", 0x7ffea1309300) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/home/henning/.var/app/org.shotcut.Shotcut/data/mime/image/png.xml", 0x7ffea1308ff0) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/app/share/mime/image/png.xml", 0x7ffea1308ff0) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/usr/share/mime/image/png.xml", {st_mode=S_IFREG|0644, st_size=2683, ...}) = 0
[pid 4413] stat("/usr/share/runtime/share/mime/image/png.xml", 0x7ffea1308ff0) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/run/host/share/mime/image/png.xml", 0x7ffea1308ff0) = -1 ENOENT (No such file or directory)
[pid 4413] open("/usr/share/mime/image/png.xml", O_RDONLY|O_CLOEXEC) = 26
[pid 4413] access("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", F_OK) = 0
[pid 4413] open("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", O_RDWR|O_CREAT|O_CLOEXEC, 0666) = 26
[pid 4413] open("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf.lock", O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 26
[pid 4413] open("/proc/sys/kernel/random/boot_id", O_RDONLY|O_CLOEXEC) = 37
[pid 4413] open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
[pid 4413] open("/usr/local/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
[pid 4413] readlink("/proc/2/exe", "/app/bin/shotcut", 256) = 16
[pid 4413] access("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", F_OK) = 0
[pid 4413] stat("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", {st_mode=S_IFREG|0664, st_size=5523, ...}) = 0
[pid 4413] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2251, ...}) = 0
[pid 4413] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2251, ...}) = 0
[pid 4413] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2251, ...}) = 0
[pid 4413] access("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", F_OK) = 0
[pid 4413] access("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", W_OK) = 0
[pid 4413] stat("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", {st_mode=S_IFREG|0664, st_size=5523, ...}) = 0
[pid 4413] lstat("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", {st_mode=S_IFREG|0664, st_size=5523, ...}) = 0
[pid 4413] open("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech", O_RDWR|O_CLOEXEC|O_TMPFILE, 0600) = 37
[pid 4413] stat("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", {st_mode=S_IFREG|0664, st_size=5523, ...}) = 0
[pid 4413] access("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", R_OK) = 0
[pid 4413] access("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", W_OK) = 0
[pid 4413] access("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", X_OK) = -1 EACCES (Permission denied)
[pid 4413] linkat(AT_FDCWD, "/proc/self/fd/37", AT_FDCWD, "/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", AT_SYMLINK_FOLLOW) = -1 EEXIST (File exists)
[pid 4413] linkat(AT_FDCWD, "/proc/self/fd/37", AT_FDCWD, "/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf.bknWSq", AT_SYMLINK_FOLLOW) = 0
[pid 4413] rename("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf.bknWSq", "/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf") = 0
[pid 4413] stat("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf", {st_mode=S_IFREG|0664, st_size=5523, ...}) = 0
[pid 4413] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2251, ...}) = 0
[pid 4413] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2251, ...}) = 0
[pid 4413] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2251, ...}) = 0
[pid 4413] unlink("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech/Shotcut.conf.lock") = 0
[pid 4413] access("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech.conf", F_OK) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech.conf", 0x7ffea1309f90) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/home/henning/.var/app/org.shotcut.Shotcut/config/Meltytech.conf", 0x7ffea1309f50) = -1 ENOENT (No such file or directory)
[pid 4413] access("/app/etc/xdg/Meltytech/Shotcut.conf", F_OK) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/app/etc/xdg/Meltytech/Shotcut.conf", 0x7ffea1309f90) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/app/etc/xdg/Meltytech/Shotcut.conf", 0x7ffea1309f50) = -1 ENOENT (No such file or directory)
[pid 4413] access("/etc/xdg/Meltytech/Shotcut.conf", F_OK) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/etc/xdg/Meltytech/Shotcut.conf", 0x7ffea1309f90) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/etc/xdg/Meltytech/Shotcut.conf", 0x7ffea1309f50) = -1 ENOENT (No such file or directory)
[pid 4413] access("/app/etc/xdg/Meltytech.conf", F_OK) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/app/etc/xdg/Meltytech.conf", 0x7ffea1309f90) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/app/etc/xdg/Meltytech.conf", 0x7ffea1309f50) = -1 ENOENT (No such file or directory)
[pid 4413] access("/etc/xdg/Meltytech.conf", F_OK) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/etc/xdg/Meltytech.conf", 0x7ffea1309f90) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/etc/xdg/Meltytech.conf", 0x7ffea1309f50) = -1 ENOENT (No such file or directory)
[pid 4413] stat("/app", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml/modules", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml/modules/Shotcut", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml/modules/Shotcut/Controls", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml/modules", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml/modules/Shotcut", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml/modules/Shotcut/Controls", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml/modules", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml/modules/Shotcut", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 4413] stat("/app/share/shotcut/qml/modules/Shotcut/Controls", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 24018] +++ exited with 0 +++
`
The flatpak uses the MLT git master from the date of the build. So, the big difference between what you are testing and myself is Qt version. The v18.11.18 flatpak (and probably also your Fedora package) of Shotcut uses Qt 5.11 while mine and the other builds (portable and appimage) are using Qt 5.6.
It seems like duplicate stats are run, two open calls for mp4 file ?
Yes, each audio/video file is opened twice with libavformat in order to maintain a/v synchronization while seeking. Ideally, it should not be needed, but that is the way it is with no plans to change it.