This is an automated email from the git hooks/post-receive script. Git pushed a commit to branch master in repository ffmpeg.
commit ea624d1e8d4712995f5652bfc12579f9f7b294d1 Author: Uraza Aru <[email protected]> AuthorDate: Wed Oct 14 02:14:02 2026 +0500 Commit: Lynne <[email protected]> CommitDate: Sat Nov 7 08:36:02 2026 +0000 avcodec/vulkan_encode_av1: zero constantQIndex when rate control is on VUID-vkCmdEncodeVideoKHR-constantQIndex-10320 requires constantQIndex to be 0 unless the rate control mode is DISABLED; the H.264 encoder already does the same for constantQp. The AV1 encoder always passed base_q_idx. On NVIDIA the frame headers then signal delta_q_present = 0 while blocks are evidently quantised differently, so every frame decodes with an error: 2560x1440 at 60 fps and 50 Mbit/s reached only 37.3 dB PSNR, and quality fell as the bitrate rose (165 fps: 40.2, 38.4 and 37.7 dB at 60, 100 and 137 Mbit/s). With this change those become 57.1 dB and 46.8, 53.9 and 59.5 dB, on par with NVIDIA's own encoder sample on the same input. Constant QP is unchanged. Fixes #25046. Assisted-by: Claude Opus 5.5 Signed-off-by: Uraza Aru <[email protected]> --- libavcodec/vulkan_encode_av1.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/libavcodec/vulkan_encode_av1.c b/libavcodec/vulkan_encode_av1.c index 9f864732df..e5d88803a4 100644 --- a/libavcodec/vulkan_encode_av1.c +++ b/libavcodec/vulkan_encode_av1.c @@ -453,6 +453,10 @@ static int init_pic_params(AVCodecContext *avctx, FFHWBaseEncodePicture *pic, .primaryReferenceCdfOnly = 0, .generateObuExtensionHeader = 0, }; + /* With rate control on, the driver picks the quantiser; constantQIndex must be 0 + * (VUID-vkCmdEncodeVideoKHR-constantQIndex-10320). */ + if (ctx->opts.rc_mode != VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DISABLED_BIT_KHR) + ap->vkav1pic_info.constantQIndex = 0; encode_info->pNext = &ap->vkav1pic_info; for (int i = 0; i < FF_ARRAY_ELEMS(ap->vkav1pic_info.referenceNameSlotIndices); i++) -- To stop receiving notification emails like this one, please contact [email protected]. _______________________________________________ ffmpeg-cvslog mailing list -- [email protected] To unsubscribe send an email to [email protected]
