On 2020-08-11 12:43, Steve Lhomme wrote:
Sorry if you seem to know all the answers already, but I don't and so
I have to
investigate.
Last year, I had literally worked this down to death. I followed every
slightest
hint from countless searches, read through hundreds of discussions,
driven
because I was unwilling to believe that up-/downloading of video
textures with
D3D11 can't be done equally fast as with D3D9.
(the big picture was the implementation of D3D11 support for QuickSync
where
the slowdown played a much bigger role than with D3D11VA decoders only).
Eventually I landed at some internal Nvidia presentation, some talks
with MS
guys and some source code discussion deep inside a 3D game engine (not a
no-name). It really bugs me that I didn't properly note the
references, but
from somewhere in between I was able to gather solid evidence about what
is legal to do and what Is not. Based on that, followed several
iterations to
find the optimal way for doing the texture transfer. As I had implemented
D3D11 support for QuickSync, this got pretty complicated because with
a full transcoding pipeline, all parts (decoder, encoder and filters)
can (and
usually will) request textures. Only the latest Intel Drivers can work
with
array textures everywhere (e.g. VPP), so I also needed to add support for
non-array texture allocation. The patch you've seen is the result of
weeks
of intensive work (a small but crucial part of it) - even when it may not
look like that.
Sorry if you seem to know all the answers already
Obviously, I don't know all the answers, but all the answers I have given
were correct. And when I didn't have an answer I always respectfully
said that your situation might be different.
And I didn't reply by implying that you would have done your work
by trial-and-error or most likely invalid assumptions or deductions.
I still don't know how you are actually operating this and thus I also
cannot
tell what might or might not work in your case.
All I can tell is that the procedure that I have described (1-2-3-4) can
work rock-solid for multi-threaded DX11 texture transfer when it's
done in
the same way as I've shown.
And believe it or not - I would still be happy when it would be
of any use for you...
Even though the discussion is heated (fitting with the weather here) I
don't mind. I learned some stuff and it pushed me to dig deeper. I can't
just accept your word for it. I need something solid if I'm going to
remove a lock that helped me so far.
So I'm currently tooling VLC to be able to bring the decoder to its
knees and find out what it can and cannot do safely. So far I can still
see decoding artifacts when I don't a lock, which would mean I still
need the mutex, for the reasons given in the previous mail.
A follow-up on this. Using ID3D10Multithread seems to be enough to have
mostly thread safe ID3D11Device/ID3D11DeviceContext/etc. Even the
decoding with its odd API seem to know what to do when submitted
different buffers.
I did not manage to saturate the GPU but I much bigger decoding
speed/throughput to validate the errors I got before. Many of them were
due to VLC dropping data because of odd timing.
Now I still have some threading issues. For example for deinterlacing we
create a ID3D11VideoProcessor to handle the deinterlacing. And we create
it after the decoding started (as the deinterlacing can be
enabled/disabled dynamically). Without the mutex in the decoder it
crashes on ID3D11VideoDevice::CreateVideoProcessor() and
ID3D11VideoContext::SubmitDecoderBuffers() as they are being called
simultaneously. If I add the mutex between the decoder and just this
filter (not the rendering side) it works fine.
So I guess I'm stuck with the mutex for the time being.
Here is the stack trace on an Intel 630 GPU:
igd11dxva64.dll!00007ffc384a8d24() (Unknown Source:0)
igd11dxva64.dll!00007ffc38452030() (Unknown Source:0)
igd11dxva64.dll!00007ffc3845a081() (Unknown Source:0)
igd11dxva64.dll!00007ffc38465a27() (Unknown Source:0)
igd11dxva64.dll!00007ffc386067d2() (Unknown Source:0)
igd11dxva64.dll!00007ffc3883c9f3() (Unknown Source:0)
igd11dxva64.dll!00007ffc3867145a() (Unknown Source:0)
igd11dxva64.dll!00007ffc3866ea23() (Unknown Source:0)
igd11dxva64.dll!00007ffc3881b4ac() (Unknown Source:0)
igd11dxva64.dll!00007ffc384f7bdc() (Unknown Source:0)
igd11dxva64.dll!00007ffc384fa2a5() (Unknown Source:0)
igd11dxva64.dll!00007ffc3847a334() (Unknown Source:0)
d3d11.dll!00007ffcabc33e8d() (Unknown Source:0)
d3d11.dll!00007ffcabc3389d() (Unknown Source:0)
d3d11_3SDKLayers.dll!00007ffc3184fa6b() (Unknown Source:0)
calling ID3D11VideoContext::SubmitDecoderBuffers()
libavcodec_plugin.dll!ff_dxva2_common_end_frame(AVCodecContext * avctx,
AVFrame * frame, const void * pp, unsigned int pp_size, const void * qm,
unsigned int qm_size, int(*)(AVCodecContext *, void *, void *)
commit_bs_si) Line 1085
(c:\Users\robux\Documents\Programs\Videolabs\build\win64\contrib\contrib-win64\ffmpeg\libavcodec\dxva2.c:1085)
libavcodec_plugin.dll!dxva2_h264_end_frame(AVCodecContext * avctx) Line
507
(c:\Users\robux\Documents\Programs\Videolabs\build\win64\contrib\contrib-win64\ffmpeg\libavcodec\dxva2_h264.c:507)
libavcodec_plugin.dll!ff_h264_field_end(H264Context * h,
H264SliceContext * sl, int in_setup) Line 171
(c:\Users\robux\Documents\Programs\Videolabs\build\win64\contrib\contrib-win64\ffmpeg\libavcodec\h264_picture.c:171)
libavcodec_plugin.dll!h264_decode_frame(AVCodecContext * avctx, void *
data, int * got_frame, AVPacket * avpkt) Line 1015
(c:\Users\robux\Documents\Programs\Videolabs\build\win64\contrib\contrib-win64\ffmpeg\libavcodec\h264dec.c:1015)
libavcodec_plugin.dll!decode_simple_internal(AVCodecContext * avctx,
AVFrame * frame) Line 432
(c:\Users\robux\Documents\Programs\Videolabs\build\win64\contrib\contrib-win64\ffmpeg\libavcodec\decode.c:432)
win32u.dll!00007ffcb0054784() (Unknown Source:0)
gdi32.dll!00007ffcb1e03860() (Unknown Source:0)
d3d11.dll!00007ffcabc756ee() (Unknown Source:0)
d3d11.dll!00007ffcabc5c811() (Unknown Source:0)
igd11dxva64.dll!00007ffc385c5043() (Unknown Source:0)
igd11dxva64.dll!00007ffc384abaa5() (Unknown Source:0)
igd11dxva64.dll!00007ffc384ab7ab() (Unknown Source:0)
igd11dxva64.dll!00007ffc38453b27() (Unknown Source:0)
igd11dxva64.dll!00007ffc384611e6() (Unknown Source:0)
igd11dxva64.dll!00007ffc385cca30() (Unknown Source:0)
igd11dxva64.dll!00007ffc384bb303() (Unknown Source:0)
igd11dxva64.dll!00007ffc3847ccff() (Unknown Source:0)
d3d11.dll!00007ffcabc3e661() (Unknown Source:0)
d3d11.dll!00007ffcabc3d39f() (Unknown Source:0)
d3d11.dll!00007ffcabc3d0cd() (Unknown Source:0)
d3d11.dll!00007ffcabc68a46() (Unknown Source:0)
d3d11.dll!00007ffcabc5955d() (Unknown Source:0)
d3d11_3SDKLayers.dll!00007ffc318a263c() (Unknown Source:0)
d3d11_3SDKLayers.dll!00007ffc3189479a() (Unknown Source:0)
d3d11_3SDKLayers.dll!00007ffc3184e749() (Unknown Source:0)
d3d11.dll!00007ffcabc59d0c() (Unknown Source:0)
d3d11.dll!00007ffcabc3c606() (Unknown Source:0)
d3d11_3SDKLayers.dll!00007ffc3187dd0e() (Unknown Source:0)
calling ID3D11VideoDevice::CreateVideoProcessor()
libdirect3d11_filters_plugin.dll!D3D11OpenDeinterlace(vlc_object_t *
obj) Line 297
(c:\Users\robux\Documents\Programs\Videolabs\vlc\modules\hw\d3d11\d3d11_deinterlace.c:297)
libvlccore.dll!generic_start(void * func, bool forced, char * ap) Line
294
(c:\Users\robux\Documents\Programs\Videolabs\vlc\src\modules\modules.c:294)
libvlccore.dll!module_load(vlc_logger * log, module_t * m, int(*)(void
*, bool, char *) init, bool forced, char * args) Line 212
(c:\Users\robux\Documents\Programs\Videolabs\vlc\src\modules\modules.c:212)
libvlccore.dll!vlc_module_load(vlc_logger * log, const char *
capability, const char * name, bool strict, int(*)(void *, bool, char *)
probe, ...) Line 265
(c:\Users\robux\Documents\Programs\Videolabs\vlc\src\modules\modules.c:265)
libvlccore.dll!module_need(vlc_object_t * obj, const char * cap, const
char * name, bool strict) Line 305
(c:\Users\robux\Documents\Programs\Videolabs\vlc\src\modules\modules.c:305)
libvlccore.dll!filter_chain_AppendInner(filter_chain_t * chain, const
char * name, const char * capability, config_chain_t * cfg, const
es_format_t * fmt_out) Line 254
(c:\Users\robux\Documents\Programs\Videolabs\vlc\src\misc\filter_chain.c:254)
libvlccore.dll!filter_chain_AppendFilter(filter_chain_t * chain, const
char * name, config_chain_t * cfg, const es_format_t * fmt_out) Line 299
(c:\Users\robux\Documents\Programs\Videolabs\vlc\src\misc\filter_chain.c:299)
libvlccore.dll!ThreadChangeFilters(vout_thread_sys_t * vout, const char
* filters, const bool * new_deinterlace, bool is_locked) Line 992
(c:\Users\robux\Documents\Programs\Videolabs\vlc\src\video_output\video_output.c:992)
libvlccore.dll!Thread(void * object) Line 1891
(c:\Users\robux\Documents\Programs\Videolabs\vlc\src\video_output\video_output.c:1891)
libvlccore.dll!vlc_entry(void * p) Line 360
(c:\Users\robux\Documents\Programs\Videolabs\vlc\src\win32\thread.c:360)
msvcrt.dll!00007ffcb139af5a() (Unknown Source:0)
msvcrt.dll!00007ffcb139b02c() (Unknown Source:0)
kernel32.dll!00007ffcb21d6fd4() (Unknown Source:0)
ntdll.dll!00007ffcb23bcec1() (Unknown Source:0)
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