ffmpeg-qsv pipelines causes app hang if vpp_qsv+fps filters present

[dvrogozh]

Summary of the bug:
I've used ffmpeg from master branch @ 4c705a2 commit w/ ffmpeg-qsv pipeline having qsv decoder, encoder, vp. If vpp_qsv and fps filters present in pipeline application hangs at the very end and dumps some warning messages - see below

How to reproduce:

$ ffmpeg -hwaccel qsv -qsv_device /dev/dri/renderD128 -c:v h264_qsv -i input.mp4 -vf "vpp_qsv=w=1920:h=1080,fps=fps=24" -c:v h264_qsv  a.mp4 -y

...
[h264_qsv @ 0x5bd49a309dc0] A decode call did not consume any data: expect more data at input (-10)
    Last message repeated 2 times
[out_0_0 @ 0x5bd49a8f9080] 100 buffers queued in out_0_0, something may be wrong.
[out_0_0 @ 0x5bd49a8f9080] 1000 buffers queued in out_0_0, something may be wrong.
[out_0_0 @ 0x5bd49a8f9080] 10000 buffers queued in out_0_0, something may be wrong.
[out_0_0 @ 0x5bd49a8f9080] 100000 buffers queued in out_0_0, something may be wrong.
[out_0_0 @ 0x5bd49a8f9080] 1000000 buffers queued in out_0_0, something may be wrong.

Culprit looks to be the following commit. When I revert it issue disappears:

commit 89ffcd1bbe1150aa07ae52a4e1545668a4e83a3e
Author: Fei Wang <fei.w.wang@intel.com>
Date:   Wed Mar 31 10:07:44 2021 +0800

    lavfi/qsvvpp: support async depth

    Async depth will allow qsv filter cache few frames, and avoid force
    switch and end filter task frame by frame. This change will improve
    performance for some multi-task case, for example 1:N transcode(
    decode + vpp + encode) with all QSV plugins.

    Performance data test on my Coffee Lake Desktop(i7-8700K) by using
    the following 1:8 transcode test case improvement:
    1. Fps improved from 55 to 130.
    2. Render/Video usage improved from ~61%/~38% to ~100%/~70%.(Data get
    from intel_gpu_top)

    test CMD:
    ffmpeg -v verbose -init_hw_device qsv=hw:/dev/dri/renderD128 -filter_hw_device                 \
     hw -hwaccel qsv -hwaccel_output_format qsv -c:v h264_qsv -i 1920x1080.264                     \
    -vf 'vpp_qsv=w=1280:h=720:async_depth=4' -c:v h264_qsv -r:v 30 -preset 7 -g 33 -refs 2 -bf 3 -q 24 -f null - \
    -vf 'vpp_qsv=w=1280:h=720:async_depth=4' -c:v h264_qsv -r:v 30 -preset 7 -g 33 -refs 2 -bf 3 -q 24 -f null - \
    -vf 'vpp_qsv=w=1280:h=720:async_depth=4' -c:v h264_qsv -r:v 30 -preset 7 -g 33 -refs 2 -bf 3 -q 24 -f null - \
    -vf 'vpp_qsv=w=1280:h=720:async_depth=4' -c:v h264_qsv -r:v 30 -preset 7 -g 33 -refs 2 -bf 3 -q 24 -f null - \
    -vf 'vpp_qsv=w=1280:h=720:async_depth=4' -c:v h264_qsv -r:v 30 -preset 7 -g 33 -refs 2 -bf 3 -q 24 -f null - \
    -vf 'vpp_qsv=w=1280:h=720:async_depth=4' -c:v h264_qsv -r:v 30 -preset 7 -g 33 -refs 2 -bf 3 -q 24 -f null - \
    -vf 'vpp_qsv=w=1280:h=720:async_depth=4' -c:v h264_qsv -r:v 30 -preset 7 -g 33 -refs 2 -bf 3 -q 24 -f null -

    Signed-off-by: Fei Wang <fei.w.wang@intel.com>
    Reviewed-by: Linjie Fu <linjie.justin.fu@gmail.com>
    Signed-off-by: Zhong Li <zhongli_dev@126.com>

[dvrogozh]

The following 2 patches seem to fix this issue:
​http://ffmpeg.org/pipermail/ffmpeg-devel/2021-June/281249.html
​http://ffmpeg.org/pipermail/ffmpeg-devel/2021-June/281250.html

[haihao]

commit efc22e63e5899f5eda8ee50fc92ecd752aedce87
Author: Haihao Xiang <​haihao.xiang@intel.com>
Date: Fri Jun 11 10:19:46 2021 +0800

lavfi/vf_vpp_qsv: fix the time_base for outlink