Hi there. Let me add some background here.
The assembly optimization of inv is too complicated to be a GSOC task. You can refer to the code of dav1d to see how it can be. https://code.videolan.org/videolan/dav1d/-/blob/master/src/x86/itx_avx2.asm?ref_type=heads. We do have an internal version of it. That's why we haven't posted and merged it yet. About the intra prediction, some function of the current C code with the compilation optimization enabled will run fast enough, so the handwritten assembly will not definitely be faster than the C code. You may need to run a performance test to evaluate it. Thanks, Jianhua ________________________________ 发件人: Frank Plowman via ffmpeg-devel <[email protected]> 发送时间: 2026年3月29日 3:20 收件人: [email protected] <[email protected]> 抄送: Frank Plowman <[email protected]> 主题: [FFmpeg-devel] Re: [GSoC 2026] Proposal/Mentorship Request: VVC x86 SIMD Optimization On 28/03/2026 16:01, Hank Li via ffmpeg-devel wrote: > Hello, > > I'm a bit late to the party, but I'm interested in proposing a GSoC > project on VVC x86 SIMD optimization. This was on the 2025 ideas list > but there are currently no SIMD overrides for itx or intra_pred in > avcodec/x86/vvc/dsp_init.c, only ALF and inter prediction have x86 > assembly. > > I would like to propose implementing: > -AVX2 inverse transforms for DCT-II, DST-VII, and DCT-VIII > -Intra prediction for DC, planar, and angular modes > -Corresponding checkasm tests and benchmarks > > For qualification, I'm currently working on a checkasm test for VVC > inverse transforms (tests/checkasm/vvc_itx.c). > > I've emailed Nuo Mi about mentoring since he mentored the VVC SIMD > projects in 2023 and 2024. If anyone else is interested in mentoring > or has thoughts, I'd appreciate it. > > Best, > Hankang Li > _______________________________________________ > ffmpeg-devel mailing list -- [email protected] > To unsubscribe send an email to [email protected] Hi, Thanks for your interest in the VVC decoder. Writing assembly optimizations for the inverse transforms will be significantly more difficult than for the intra prediction I believe. There isn't much precedent for rectangular transforms available, whereas the intra prediction functions are largely similar to HEVC's only with an increased number of taps. Perhaps a more suitable plan would be to begin with the intra prediction functions and then to have the inverse transform functions as a "stretch goal". I don't know how familiar you are with AVX2 and video coding, but that would represent a more natural introduction and progression of difficulty. -- Frank _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
