ffmpeg | branch: release/7.1 | Janne Grunau <janne-ffm...@jannau.net> | Fri Jan 3 01:54:38 2025 +0100| [1a254c5354fb58c694603fdedd60923cf368c46f] | committer: Ronald S. Bultje
aarch64: vp9mc: Load only 12 pixels in the 4 pixel wide horizontal filter This reduces the amount the horizontal filters read beyond the filter width to a consistent 1 pixel. The data is not used so this is usually not noticeable. It becomes a problem when the application allocates frame buffers only for the aligned picture size and the end of it is at a page boundary. This happens for picture sizes which are a multiple of the page size like 1280x640. The frame buffer allocation is based on its most likely done via mmap + MAP_ANONYMOUS so start and end of the buffer are page aligned and the previous and next page are not necessarily mapped. Under these conditions like seen by Firefox a read beyond the end of the buffer results in a segfault. After the over-read is reduced to a single pixel it's reasonable to use VP9's emulated edge motion compensation for this. Fixes: https://bugzilla.mozilla.org/show_bug.cgi?id=1881185 Signed-off-by: Janne Grunau <janne-ffm...@jannau.net> Signed-off-by: Ronald S. Bultje <rsbul...@gmail.com> (cherry picked from commit 430c38f698a65d597e863330810b05e083682be6) > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1a254c5354fb58c694603fdedd60923cf368c46f --- libavcodec/aarch64/vp9mc_neon.S | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/libavcodec/aarch64/vp9mc_neon.S b/libavcodec/aarch64/vp9mc_neon.S index abf2bae9db..38f44ca56d 100644 --- a/libavcodec/aarch64/vp9mc_neon.S +++ b/libavcodec/aarch64/vp9mc_neon.S @@ -230,6 +230,9 @@ function \type\()_8tap_\size\()h_\idx1\idx2 // reduced dst stride .if \size >= 16 sub x1, x1, x5 +.elseif \size == 4 + add x12, x2, #8 + add x13, x7, #8 .endif // size >= 16 loads two qwords and increments x2, // for size 4/8 it's enough with one qword and no @@ -248,9 +251,14 @@ function \type\()_8tap_\size\()h_\idx1\idx2 .if \size >= 16 ld1 {v4.8b, v5.8b, v6.8b}, [x2], #24 ld1 {v16.8b, v17.8b, v18.8b}, [x7], #24 -.else +.elseif \size == 8 ld1 {v4.8b, v5.8b}, [x2] ld1 {v16.8b, v17.8b}, [x7] +.else // \size == 4 + ld1 {v4.8b}, [x2] + ld1 {v16.8b}, [x7] + ld1 {v5.s}[0], [x12], x3 + ld1 {v17.s}[0], [x13], x3 .endif uxtl v4.8h, v4.8b uxtl v5.8h, v5.8b _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
