Your message dated Tue, 20 Oct 2026 19:50:10 +0000
with message-id <[email protected]>
and subject line Bug#1151366: fixed in svt-av1 4.2.0+dfsg-2
has caused the Debian Bug report #1151366,
regarding libsvtav1enc4 triggers segmentation fault
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
(NB: If you are a system administrator and have no idea what this
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--
1151366: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1151366
Debian Bug Tracking System
Contact [email protected] with problems
--- Begin Message ---
Package: libsvtav1enc4
Version: 4.2.0+dfsg-1
Severity: important
Dear Maintainer,
The latest version of the svt-av1 encoder library triggers a
segmentation fault in ffmpeg and SvtAv1EncApp. This is the problematic
version:
libsvtav1enc4_4.2.0+dfsg-1_amd64.deb
The segmentation fault occurs when I use ffmpeg with the option "-c:v
libsvtav1" but also occurs when I use SvtAv1EncApp directly. So I
believe this is not just an ffmpeg bug.
With the assistance of Cat-GPT-6, I produced a gdb trace of the
segmentation fault as it occurs with ffmpeg. The error output is
appended to the end of this bug report.
$ gdb -q -batch -ex 'set pagination off' -ex run -ex 'bt 8' --args
ffmpeg -hide_banner -loglevel error -nostdin -y -i test.mp4 -c:v
libsvtav1 /tmp/svt42-test.webm > /tmp/svt42-gdb.txt 2>&1; tail -n 25
/tmp/svt42-gdb.txt
The segmenatation fault doesn't happen when I run ffmpeg with the
previous version of libsvtav1enc4, namely:
libsvtav1enc4_4.1.0+dfsg-1_amd64.deb
-- System Information:
Debian Release: forky/sid
APT prefers testing
APT policy: (900, 'testing'), (90, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386, arm64
Kernel: Linux 7.1.7+deb14-amd64 (SMP w/4 CPU threads; PREEMPT)
Kernel taint flags: TAINT_CPU_OUT_OF_SPEC
Locale: LANG=en_SG.UTF-8, LC_CTYPE=en_SG.UTF-8 (charmap=UTF-8), LANGUAGE
not set
Shell: /bin/sh linked to /usr/bin/dash
Init: sysvinit (via /sbin/init)
LSM: AppArmor: enabled
Versions of packages libsvtav1enc4 depends on:
ii libc6 2.43-7
-- BEGIN GDB OUTPUT
[Thread debugging using libthread_db enabled]
Using host libthread_db library
"/usr/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffea2a96c0 (LWP 14049) (id 2)]
[New Thread 0x7fffe9aa86c0 (LWP 14050) (id 3)]
[New Thread 0x7fffe92a76c0 (LWP 14051) (id 4)]
[New Thread 0x7fffe8aa66c0 (LWP 14052) (id 5)]
[New Thread 0x7fffe82a56c0 (LWP 14053) (id 6)]
[New Thread 0x7fffe7aa46c0 (LWP 14054) (id 7)]
[New Thread 0x7fffe72a36c0 (LWP 14055) (id 8)]
[New Thread 0x7fffe6aa26c0 (LWP 14056) (id 9)]
[New Thread 0x7fffe62a16c0 (LWP 14057) (id 10)]
[New Thread 0x7fffe54a36c0 (LWP 14058) (id 11)]
[New Thread 0x7fffe4aa36c0 (LWP 14059) (id 12)]
[New Thread 0x7fffc7fff6c0 (LWP 14060) (id 13)]
[New Thread 0x7fffc77fe6c0 (LWP 14061) (id 14)]
Svt[info]: -------------------------------------------
Svt[info]: SVT [version]: SVT-AV1 Encoder Lib v4.2.0
Svt[info]: SVT [build] : GCC 16.2.0 64 bit
Svt[info]: -------------------------------------------
Svt[info]: Level of Parallelism: 3
Svt[info]: Number of PPCS 42
Svt[info]: [asm level on system : up to sse4_1]
Svt[info]: [asm level selected : up to sse4_1]
Svt[info]: -------------------------------------------
Svt[info]: SVT [config]: main profile tier (auto) level (auto)
Svt[info]: SVT [config]: width / height / fps numerator / fps
denominator : 1920 / 1080 / 43 / 3
Svt[info]: SVT [config]: bit-depth / color format
: 8 / YUV420
Svt[info]: SVT [config]: preset / tune / pred struct : 8 / PSNR /
random access
Svt[info]: SVT [config]: gop size / mini-gop size / key-frame type :
81 / 16 / key frame
Svt[info]: SVT [config]: BRC mode / rate factor
: CRF / 35.00
Svt[info]: SVT [config]: AQ mode / Variance Boost
: 2 / 0
Svt[info]: SVT [config]: sharpness / luminance-based QP bias
: 0 / 0
Svt[info]: SVT [config]: QP scale compress strength
: 0
Svt[info]: -------------------------------------------
[New Thread 0x7fffb81f66c0 (LWP 14062) (id 15)]
[New Thread 0x7fffac1966c0 (LWP 14063) (id 16)]
[New Thread 0x7fffa41556c0 (LWP 14064) (id 17)]
[New Thread 0x7fff9c4796c0 (LWP 14065) (id 18)]
[New Thread 0x7fff9c3786c0 (LWP 14066) (id 19)]
[New Thread 0x7fff9c2776c0 (LWP 14067) (id 20)]
[New Thread 0x7fff9c1766c0 (LWP 14068) (id 21)]
[New Thread 0x7fff7ffff6c0 (LWP 14069) (id 22)]
[New Thread 0x7fff7fefe6c0 (LWP 14070) (id 23)]
[New Thread 0x7fff7fdfd6c0 (LWP 14071) (id 24)]
[New Thread 0x7fff7fcfc6c0 (LWP 14072) (id 25)]
[New Thread 0x7fff7fbfb6c0 (LWP 14073) (id 26)]
[New Thread 0x7fff7fafa6c0 (LWP 14074) (id 27)]
[New Thread 0x7fff7f9f96c0 (LWP 14075) (id 28)]
[New Thread 0x7fff7f8f86c0 (LWP 14076) (id 29)]
[New Thread 0x7fff7f7f76c0 (LWP 14077) (id 30)]
[New Thread 0x7fff7f6f66c0 (LWP 14078) (id 31)]
[New Thread 0x7fff7f5f56c0 (LWP 14079) (id 32)]
[New Thread 0x7fff7f4f46c0 (LWP 14080) (id 33)]
[New Thread 0x7fff7f3f36c0 (LWP 14081) (id 34)]
[New Thread 0x7fff7f2f26c0 (LWP 14082) (id 35)]
[New Thread 0x7fff7f1f16c0 (LWP 14083) (id 36)]
[New Thread 0x7fff7f0f06c0 (LWP 14084) (id 37)]
[New Thread 0x7fff7efef6c0 (LWP 14085) (id 38)]
[New Thread 0x7fff7eeee6c0 (LWP 14086) (id 39)]
[New Thread 0x7fff7eded6c0 (LWP 14087) (id 40)]
[New Thread 0x7fff7ecec6c0 (LWP 14088) (id 41)]
[New Thread 0x7fff7ebeb6c0 (LWP 14090) (id 42)]
[New Thread 0x7fff7eaea6c0 (LWP 14091) (id 43)]
[New Thread 0x7fff7e9e96c0 (LWP 14092) (id 44)]
[New Thread 0x7fff7e8e86c0 (LWP 14093) (id 45)]
[New Thread 0x7fff7e7e76c0 (LWP 14094) (id 46)]
[New Thread 0x7fff7e6e66c0 (LWP 14095) (id 47)]
[New Thread 0x7fff7e5e56c0 (LWP 14096) (id 48)]
[New Thread 0x7fff7e4e46c0 (LWP 14097) (id 49)]
[New Thread 0x7fff7e3e36c0 (LWP 14098) (id 50)]
[New Thread 0x7fff7e2e26c0 (LWP 14099) (id 51)]
[New Thread 0x7fff7e1e16c0 (LWP 14100) (id 52)]
[New Thread 0x7fff7e0e06c0 (LWP 14101) (id 53)]
[New Thread 0x7fff7dfdf6c0 (LWP 14102) (id 54)]
[New Thread 0x7fff7dede6c0 (LWP 14103) (id 55)]
[New Thread 0x7fff7dddd6c0 (LWP 14104) (id 56)]
[New Thread 0x7fff7dcdc6c0 (LWP 14105) (id 57)]
[New Thread 0x7fff7dbdb6c0 (LWP 14106) (id 58)]
[New Thread 0x7fff7dada6c0 (LWP 14107) (id 59)]
[New Thread 0x7fff7d9d96c0 (LWP 14108) (id 60)]
[New Thread 0x7fff7d8d86c0 (LWP 14109) (id 61)]
[New Thread 0x7fff7d7d76c0 (LWP 14110) (id 62)]
[New Thread 0x7fff7d6d66c0 (LWP 14111) (id 63)]
[New Thread 0x7fff7d5d56c0 (LWP 14112) (id 64)]
[New Thread 0x7fff7d4d46c0 (LWP 14113) (id 65)]
[New Thread 0x7fff7d3d36c0 (LWP 14114) (id 66)]
[New Thread 0x7fff7d2d26c0 (LWP 14115) (id 67)]
[New Thread 0x7fff7d1d16c0 (LWP 14116) (id 68)]
[New Thread 0x7fff7d0d06c0 (LWP 14117) (id 69)]
[New Thread 0x7fff7cfcf6c0 (LWP 14118) (id 70)]
[New Thread 0x7fff7cece6c0 (LWP 14119) (id 71)]
[New Thread 0x7fff7cdcd6c0 (LWP 14120) (id 72)]
[New Thread 0x7fff7cccc6c0 (LWP 14121) (id 73)]
[New Thread 0x7fff7cbcb6c0 (LWP 14122) (id 74)]
[New Thread 0x7fff7caca6c0 (LWP 14123) (id 75)]
[New Thread 0x7fff7c9c96c0 (LWP 14124) (id 76)]
[Thread 0x7fffe62a16c0 (LWP 14057) (id 10) exited]
Thread 56 "svt-md1" received signal SIGSEGV, Segmentation fault.
[Switching to thread 56 (Thread 0x7fff7dddd6c0 (LWP 14104))]
0x00007fffee42fed5 in svt_aom_sub_pixel_variance16xh_ssse3 () from
/usr/lib/x86_64-linux-gnu/libSvtAv1Enc.so.4
#0 0x00007fffee42fed5 in svt_aom_sub_pixel_variance16xh_ssse3 () from
/usr/lib/x86_64-linux-gnu/libSvtAv1Enc.so.4
#1 0x00007fffee1070fa in ?? () from
/usr/lib/x86_64-linux-gnu/libSvtAv1Enc.so.4
#2 0x00007fffedfe50b0 in ?? () from
/usr/lib/x86_64-linux-gnu/libSvtAv1Enc.so.4
#3 0x00007fffee000ce4 in ?? () from
/usr/lib/x86_64-linux-gnu/libSvtAv1Enc.so.4
#4 0x00007fffedffd2de in ?? () from
/usr/lib/x86_64-linux-gnu/libSvtAv1Enc.so.4
#5 0x00007fffedeb64cb in ?? () from
/usr/lib/x86_64-linux-gnu/libSvtAv1Enc.so.4
#6 0x00007fffedeb9479 in ?? () from
/usr/lib/x86_64-linux-gnu/libSvtAv1Enc.so.4
#7 0x00007fffee05c4ad in ?? () from
/usr/lib/x86_64-linux-gnu/libSvtAv1Enc.so.4
-- END GDB OUTPUT
--- End Message ---
--- Begin Message ---
Source: svt-av1
Source-Version: 4.2.0+dfsg-2
Done: Sebastian Ramacher <[email protected]>
We believe that the bug you reported is fixed in the latest version of
svt-av1, which is due to be installed in the Debian FTP archive.
A summary of the changes between this version and the previous one is
attached.
Thank you for reporting the bug, which will now be closed. If you
have further comments please address them to [email protected],
and the maintainer will reopen the bug report if appropriate.
Debian distribution maintenance software
pp.
Sebastian Ramacher <[email protected]> (supplier of updated svt-av1 package)
(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing [email protected])
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512
Format: 1.8
Date: Tue, 20 Oct 2026 21:29:38 +0200
Source: svt-av1
Architecture: source
Version: 4.2.0+dfsg-2
Distribution: unstable
Urgency: medium
Maintainer: Debian Multimedia Maintainers <[email protected]>
Changed-By: Sebastian Ramacher <[email protected]>
Closes: 1151366
Changes:
svt-av1 (4.2.0+dfsg-2) unstable; urgency=medium
.
* debian/patches: Apply upstream patch to fix unaligned load (Closes:
#1151366)
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