[Bug]: Artifacts present in hevcencode output with B-frames

[cfoch]

Which component impacted?

No response

Is it regression? Good in old configuration?

None

What happened?

Which component impacted?

No response

Is it regression? Good in old configuration?

None

What happened?

1. In Linux or Browser or Applications...

Hardware: 13th Gen Intel(R) Core(TM) i7-1355U
cpuinfo.txt
OS: 24.04.1 LTS (Noble Numbat)
Application: hevcencode from libva-utils @ b4abf4e2 and GStreamer 1.24.2

2. With libva/libva-utils/gmmlib/media-driver version

libva-utils version: b4abf4e2 (master)
libva version: 2.23.0.pre1
gmmlib version: 3a256e6762eedd971a56f67804d8a57eb4239c6e (master)
media-driver version: intel-media-25.4.5

3. Run hevcencode

ffmpeg -y -f lavfi -i testsrc=size=1920x1080:rate=30 -t 10 -pix_fmt nv12 output_nv12.yuv
./encode/hevcencode  --srcyuv output_nv12.yuv   -w 1920 -h 1080  --fourcc NV12 -n 300 --ip_period 3  --intra_period 10  -o output.h265

After playing it back with ffplay, artifacts are displayed (and a similar behaviour happens with gstreamer):

File output attached:

output.zip

What's the usage scenario when you are seeing the problem?

Playback, Transcode for media delivery

What impacted?

No response

Debug Information

No response

Do you want to contribute a patch to fix the issue?

None