v4l-utils source now includes a tool called v4l2-tracer. This tools let you wrap a V4L2 application and trace its interaction with V4L2 drivers. The trace can also be replayed, which is common way to reproduce codec issues without the need for the original software that triggers the issue. This is a feature request of course, this tracer requires json-c library. The tools also has a man page.
"Tool to trace, record and replay userspace applications that implement the v4l2 memory-to-memory stateless video decoder interface." As we're currently 'playing' with v4l2request stateless video decoder, which IIUC uses m2m, this sounds potentially useful. So a +1 from me on this feature request. Cheers, Diederik
Hello, Bug #1093152 in libv4l reported by you has been fixed in the Git repository and is awaiting an upload. You can see the commit message below and you can check the diff of the fix at: https://salsa.debian.org/debian/libv4l/-/commit/ff08c3715bf30da1ead4abc2c189d4a721b11f8c ------------------------------------------------------------------------ enable build of v4l2-tracer (Closes: #1093152) Closes: #9 ------------------------------------------------------------------------ (this message was generated automatically) -- Greetings https://bugs.debian.org/1093152
We believe that the bug you reported is fixed in the latest version of v4l-utils, 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 1093152@bugs.debian.org, and the maintainer will reopen the bug report if appropriate. Debian distribution maintenance software pp. Gregor Jasny <gjasny@googlemail.com> (supplier of updated v4l-utils 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 ftpmaster@ftp-master.debian.org) Format: 1.8 Date: Sun, 05 Oct 2025 12:24:35 +0200 Source: v4l-utils Architecture: source Version: 1.32.0-1 Distribution: unstable Urgency: medium Maintainer: Gregor Jasny <gjasny@googlemail.com> Changed-By: Gregor Jasny <gjasny@googlemail.com> Closes: 1093152 1095303 Changes: v4l-utils (1.32.0-1) unstable; urgency=medium . [ Gregor Jasny ] * Import latest 1.32.0 upstream release . [ Diederik de Haas ] * Add missing v4l-utils tools descriptions (Closes: #1095303) . [ Jianfeng Liu ] * Enable build of v4l2-tracer (Closes: #1093152) . [ Sean Young ] * Move ir-ctl from v4l-utils to ir-keytable package Checksums-Sha1: 814622314ef7721cfff768fbc9b310ff636af5d7 3257 v4l-utils_1.32.0-1.dsc e654de9c1bf01eb221326eea04f3c0643a73656d 1384024 v4l-utils_1.32.0.orig.tar.xz 2ca499ea893134874f8c0982a6148f069615a392 833 v4l-utils_1.32.0.orig.tar.xz.asc 8cb5b59604a600f38b29fb1d33a7a8b3298ae9b4 23340 v4l-utils_1.32.0-1.debian.tar.xz b4e4c5061687670b40e9f4af37c3183a30c322a3 18068 v4l-utils_1.32.0-1_arm64.buildinfo Checksums-Sha256: e631731081368366491a1cba116c0ee79e18ca75b44062d505bf538355a209c0 3257 v4l-utils_1.32.0-1.dsc 6828828a17775526eb93fb258a9294d1d1073d633c344dd71ecd4e7a1ffb7dfc 1384024 v4l-utils_1.32.0.orig.tar.xz 56fbd3f61b8ee4719ee597b578eb7ab5c396ef2fa16a6ce303f7c5a51a115e40 833 v4l-utils_1.32.0.orig.tar.xz.asc 38412238d241b023e18ad2bf3e7e0645fcdf850e0685e3688fd6507b9121ce2f 23340 v4l-utils_1.32.0-1.debian.tar.xz 53d06f279c7e45137d69a6caf8eccb0aaf01a44b2e77146b3ef88270296ab6a3 18068 v4l-utils_1.32.0-1_arm64.buildinfo Files: 46902d57a60ab21a02a05bdeab89bfbb 3257 video optional v4l-utils_1.32.0-1.dsc c484b0320a757bd08a785cad7b32147a 1384024 video optional v4l-utils_1.32.0.orig.tar.xz 5a7f97469ffea5563d5651d4cd138722 833 video optional v4l-utils_1.32.0.orig.tar.xz.asc 377186de77d3e86dc66c59ee84facd99 23340 video optional v4l-utils_1.32.0-1.debian.tar.xz 354a3a9c18288cd20ddb0705705d2dee 18068 video optional v4l-utils_1.32.0-1_arm64.buildinfo -----BEGIN PGP SIGNATURE----- iQJKBAEBCgA0FiEEBdAWnCbkFZNBgSnfGZpk+t+1AP8FAmjiUNYWHGdqYXNueUBn b29nbGVtYWlsLmNvbQAKCRAZmmT637UA/0e8D/sH4cPwRiqLrkNGGIxU9Gn2X+5I c59qWc6YKikGTPl8QhCnUZHe6K5QIN+DWDuLTfqmpzLRNnEpdpiX7G+StkrM8hod wxYscDFFRaYXB1mc8Seh8SmNHD/Wa1Dm+GmUtwXT2QZ13wA/m6Es9ik0a89pS4Bi LZXMOercuOIRmzhkygpiV3W8qLtmyiCvorM/haDJ5UABGcfikljLdFA/vITTDD8J 2iBFB2W2BhEqNpDBsOaXdMJESEn0tCY1cMsNrpw10/hokkxUD+3MMWboFeqKR9hl 0pOd/aRdTo6ba6Flev1nXzCyl2gdIQKpeD3SZoBxmLKUcWnFzcrFDuSLP1m8c7n+ Ek3Qs0Hz/e9FYvbk244CfRxmS6pBrOC8hMWeo7aTCcRs06PV3D17j0W64GUKxTsH nk8/Ij82D5DNY1e8OrjZA2F/jY5bFle8o//rQhMKAkpqjPTGVm6M7voBC5bB6iKG mr9p0FqBc88PRj/Vu0cDBvJGXXEvl1a1Qg17bkiiLBA6S6bHJjxQdEDxXJqrM05s NfKqYB04wMq+59xoMsbf/LdBZ0WyULq1IzOV5k9CiRoL5XjTT/Sbjb9vaTxOtFA7 oW2jRXjuv2iVjyEtSCIyjcKGkddZuQw/npmMkSnlWjJ5r75OhpaHI1rXQK/LuXFu JVo3jfeDTbsGxFTgiQ== =RRC6 -----END PGP SIGNATURE-----