Update x265 to 4.2, enable HEVC alpha encoding
https://bitbucket.org/multicoreware/x265_git/downloads/x265_4.2.tar.gz Patch (git am) attached put file in thirdparty/src, patch sources, autogen.sh then build as usual In theory now for h265.mp4 you can select yuva420/yuva420p10, but I am not sure it works as intended ... decoding says alpha present (if I set loglevel=debug in decode.opts) but other sources including ffprobe from ffmpeg-8.1 detect just yuvj420p ? Tested only on Rosa 2016 x86-64 chroot
On Sat, May 9, 2026 at 3:34 AM Andrew Randrianasulu <randrianasulu@gmail.com> wrote:
https://bitbucket.org/multicoreware/x265_git/downloads/x265_4.2.tar.gz
Patch (git am) attached
put file in thirdparty/src, patch sources, autogen.sh then build as usual
In theory now for h265.mp4 you can select yuva420/yuva420p10, but I am not sure it works as intended ...
decoding says alpha present (if I set loglevel=debug in decode.opts) but other sources including ffprobe from ffmpeg-8.1 detect just yuvj420p ?
More hevc test files at https://lf-tk-sg.ibytedtos.com/obj/tcs-client-sg/resources/video_demo_hevc.h... I loaded one with transparency but it does not work for me? At least in cingg I also created alpha h265 profile setting fourcc to hvc1/0x31637668 for better Apple compatibility https://trac.ffmpeg.org/ticket/7965 I also failed to create standalone fourcc utility converting string to 4byte code, so i just used value reported by ffmpeg/ffprobe
Tested only on Rosa 2016 x86-64 chroot
I have added x265 update to 4.2 to GIT along with the 3 patches (assuming the current x265_4.0.patch4 is no longer needed?). However, I did NOT checkin 0002-Add-simple-hevc-alpha-encode-profile-with-hvc1-tag.patch which sort of works because when I mod it with 0003-Fix-h265_alpha-profile.patch and then load the rendering file created with it, it crashes. It is important to know that the ffmpeg-8.1.patch11 and patch12 were in that build too. I did not checkin 0004-Add-two-patches-for-decoding-hevc-alpha.patch because of the crash and I did not have any time to determine cause of crash. On Fri, May 8, 2026 at 6:34 PM Andrew Randrianasulu <randrianasulu@gmail.com> wrote:
https://bitbucket.org/multicoreware/x265_git/downloads/x265_4.2.tar.gz
Patch (git am) attached
put file in thirdparty/src, patch sources, autogen.sh then build as usual
In theory now for h265.mp4 you can select yuva420/yuva420p10, but I am not sure it works as intended ...
decoding says alpha present (if I set loglevel=debug in decode.opts) but other sources including ffprobe from ffmpeg-8.1 detect just yuvj420p ?
Tested only on Rosa 2016 x86-64 chroot
On Fri, May 15, 2026 at 1:49 AM Phyllis Smith <phylsmith2017@gmail.com> wrote:
I have added x265 update to 4.2 to GIT along with the 3 patches (assuming the current x265_4.0.patch4 is no longer needed?)
Yeah, this code modified by patch 4 in CMakeLists.txt changed upstream and hopefully now handle both old and post 4.0 cmake. I hope Andrea will tell us how it works on Arch? .
However, I did NOT checkin 0002-Add-simple-hevc-alpha-encode-profile-with-hvc1-tag.patch which sort of works because when I mod it with 0003-Fix-h265_alpha-profile.patch and then load the rendering file created with it, it crashes. It is important to know that the ffmpeg-8.1.patch11 and patch12 were in that build too. I did not checkin 0004-Add-two-patches-for-decoding-hevc-alpha.patch because of the crash and I did not have any time to determine cause of crash.
I think I got crash on x86-64 Rosa when I tried to enlarge jpeg asset on second vtrack over x265 alpha encoded hevc file but no crash in external i586 compiled ffplay. From quick gdb'ing around crash was in ffmpeg depths... may be some recent (post may 7) patch to hevc decoding fixed it? https://source.ffmpeg.org/gitweb/ffmpeg.git/commit/3b939ced79655ed084e6bebc4... avcodec/hevc: limit missing-ref fill to coded planes I'll try to check this idea....
On Fri, May 8, 2026 at 6:34 PM Andrew Randrianasulu <randrianasulu@gmail.com> wrote:
https://bitbucket.org/multicoreware/x265_git/downloads/x265_4.2.tar.gz
Patch (git am) attached
put file in thirdparty/src, patch sources, autogen.sh then build as usual
In theory now for h265.mp4 you can select yuva420/yuva420p10, but I am not sure it works as intended ...
decoding says alpha present (if I set loglevel=debug in decode.opts) but other sources including ffprobe from ffmpeg-8.1 detect just yuvj420p ?
Tested only on Rosa 2016 x86-64 chroot
participants (2)
-
Andrew Randrianasulu -
Phyllis Smith