[FFmpeg-user] Clarification for decoding AV1 input on the GPU
Mario Roy
marioeroy at gmail.com
Wed Jul 20 16:02:23 EEST 2022
Thank you Haihao, for the URL to patchset.
Previously, I applied only the patch contained in the email thread. This
time, I applied both patches to FFmpeg master and confirmed that
av1(native) is used for nvdec, vaapi, and vdpau. I observed 100% and 50% ~
68% video engine utilization for VP9 and AV1 respectively. Unix time is
captured for output.ts.
Video Engine Utilization: 100%
$ ffmpeg -y -hwaccel nvdec -i input_vp9.webm -f null - # GPU fps=1441
$ ffmpeg -y -hwaccel vaapi -i input_vp9.webm -f null - # GPU fps=1320
$ ffmpeg -y -hwaccel vdpau -i input_vp9.webm -f null - # GPU fps=1308
Video Engine Utilization: 50% ~ 68%
$ ffmpeg -y -hwaccel nvdec -i input_av1.mp4 -f null - # GPU fps=900
$ ffmpeg -y -hwaccel vaapi -i input_av1.mp4 -f null - # GPU fps=760
$ ffmpeg -y -hwaccel vdpau -i input_av1.mp4 -f null - # GPU fps=799
Unix Time output.ts:
-hwaccel vdpau is unexpectedly slow for av1
$ time ffmpeg -y -hwaccel nvdec -i input_vp9.webm output.ts # GPU 6.176s
$ time ffmpeg -y -hwaccel vaapi -i input_vp9.webm output.ts # GPU 7.754s
$ time ffmpeg -y -hwaccel vdpau -i input_vp9.webm output.ts # GPU 7.213s
$ time ffmpeg -y -hwaccel nvdec -i input_av1.mp4 output.ts # GPU 8.709s
$ time ffmpeg -y -hwaccel vaapi -i input_av1.mp4 output.ts # GPU 10.816s
$ time ffmpeg -y -hwaccel vdpau -i input_av1.mp4 output.ts # GPU 15.162s
The next two commands core dumps using FFmpeg master, ditto for FFmpeg 5.1.
$ ffmpeg -y -hwaccel vdpau -c:v vp9_cuvid -i input_vp9.webm -f null - #
core dumped
$ ffmpeg -y -hwaccel vdpau -c:v av1_cuvid -i input_av1.mp4 -f null - #
core dumped
No issues for nvdec. Passing -c:v av1_cuvid is swift, compared to 900 fps
above without -c:v av1_cuvid.
$ ffmpeg -y -hwaccel nvdec -c:v vp9_cuvid -i input_vp9.webm -f null - #
fps=1435
$ ffmpeg -y -hwaccel nvdec -c:v av1_cuvid -i input_av1.mp4 -f null - #
fps=1642
Thanks,
Mario
On Wed, Jul 20, 2022 at 4:30 AM Xiang, Haihao <
haihao.xiang-at-intel.com at ffmpeg.org> wrote:
>
> > Thank you, Haihao. I applied the patchset to FFmpeg 5.1 branch. Passing
> > -hwaccel {nvdec|vdpau} without -c:v av1 still decoded on the CPU. I
> double
> > checked to be sure the patchset was applied.
> >
>
> libdav1d is still used for format probing but av1(native) should be used
> for
> decoding when -hwaccel xxx is specified.
>
> I rebased the patches on the master(
> https://github.com/xhaihao/FFmpeg/tree/ffmpeg-choose-dec) however I don't
> have
> the environment to verify nvdec/vdpau. I verified it with vaapi
>
> $ ffmpeg -hwaccel vaapi -i av1.ivf -f null -
>
> [...]
> Stream mapping:
> Stream #0:0 -> #0:0 (av1 (native) -> wrapped_avframe (native))
>
> $ ffmpeg -i av1.ivf -f null -
>
> [...]
> Stream mapping:
> Stream #0:0 -> #0:0 (av1 (libdav1d) -> wrapped_avframe (native))
>
> Thanks
> Haihao
>
>
> > I obtained AV1 and VP9 samples via yt-dlp: 1920x1080 resolution.
> >
> > $ yt-dlp -F https://youtu.be/mIAfxj7nd9k
> > $ yt-dlp -f 399 https://youtu.be/mIAfxj7nd9k -o input_av1.mp4
> > $ yt-dlp -f 248 https://youtu.be/mIAfxj7nd9k -o input_vp9.webm
> >
> > Hardware: GeForce RTX 3070 FE
> >
> > AV1 Observations.
> >
> > $ ffmpeg -y -hwaccel nvdec -c:v av1_cuvid -i input_av1.mp4 output.ts #
> > GPU fps=653
> > $ ffmpeg -y -hwaccel vdpau -c:v av1_cuvid -i input_av1.mp4 output.ts #
> > Core Dumps
> > $ ffmpeg -y -hwaccel nvdec -c:v av1 -i input_av1.mp4 output.ts #
> > GPU fps=454
> > $ ffmpeg -y -hwaccel vdpau -c:v av1 -i input_av1.mp4 output.ts #
> > GPU fps=246
> > $ ffmpeg -y -hwaccel nvdec -i input_av1.mp4 output.ts #
> > CPU libdav1d
> > $ ffmpeg -y -hwaccel vdpau -i input_av1.mp4 output.ts #
> > CPU libdav1d
> >
> > VP9 Observations.
> >
> > $ ffmpeg -y -hwaccel nvdec -c:v vp9_cuvid -i input_vp9.webm output.ts #
> > GPU fps=669
> > $ ffmpeg -y -hwaccel vdpau -c:v vp9_cuvid -i input_vp9.webm output.ts #
> > Core Dumps
> > $ ffmpeg -y -hwaccel nvdec -c:v vp9 -i input_vp9.webm output.ts #
> > GPU fps=662
> > $ ffmpeg -y -hwaccel vdpau -c:v vp9 -i input_vp9.webm output.ts #
> > GPU fps=529
> > $ ffmpeg -y -hwaccel nvdec -i input_vp9.webm output.ts #
> > GPU fps=655
> > $ ffmpeg -y -hwaccel vdpau -i input_vp9.webm output.ts #
> > GPU fps=533
> >
> > Looking at the AV1 results, -hwaccel vdpau -c:v av1 is nearly 2x slower
> > than -hwaccel nvdec -c:v av1.
> >
> > Should FFmpeg exit gracefully if passing unsupported options for -hwaccel
> > vdpau? Or is this a bug?
> > -hwaccel vdpau -c:v av1_cuvid # Crashes
> > -hwaccel vdpau -c:v vp9_cuvid # Crashes
> >
> > Thanks,
> > Mario
> >
> > On Tue, Jul 19, 2022 at 8:42 PM Xiang, Haihao <
> > haihao.xiang-at-intel.com at ffmpeg.org> wrote:
> >
> > > On Tue, 2022-07-19 at 16:54 -0500, Mario Roy wrote:
> > > > Greetings,
> > > >
> > > > With the recent FFmpeg 5.1 supporting AV1 using VDPAU, should
> decoding
> > >
> > > AV1
> > > > occur on the GPU automatically (NVIDIA 3000 series), similarly to
> > >
> > > decoding
> > > > VP9?
> > > >
> > > > ffmpeg -y -hwaccel vdpau -i input_av1.mp4 output.ts # decodes on
> the
> > >
> > > CPU
> > >
> > >
> > > libdav1d has higher priority than the the native av1 decoder in
> FFmpeg, you
> > > should specify the native av1 in your command line if you want to use
> > > vdpau.
> > >
> > > $ ffmpeg -y -hwaccel vdpau -c:v av1 -i input_av1.mp4 output.ts
> > >
> > > Or you may try
> > >
> > >
>
> https://patchwork.ffmpeg.org/project/ffmpeg/patch/20210922074207.19451-2-haihao.xiang@intel.com/
> > > which can decode AV1 on the GPU automatically when -hwaccel xxx is
> > > specified in
> > > the command line. (You need to rebase the patchset).
> > >
> > > Thanks
> > > Haihao
> > >
> > >
> > > > ffmpeg -y -hwaccel vdpau -i input_vp9.webm output.ts # decodes on
> the
> > >
> > > GPU
> > > >
> > > > Are the following incorrect usage? Both segfaults.
> > > >
> > > > ffmpeg -y -hwaccel vdpau -c:v av1_cuvid -i input_av1.mp4 output.ts
> #
> > > > segfaults
> > > > ffmpeg -y -hwaccel vdpau -c:v vp9_cuvid -i input_vp9.webm output.ts
> #
> > > > segfaults
> > > >
> > > > Thanks,
> > > > Mario
> > > >
> > > > On Wed, Jul 13, 2022 at 9:44 AM Mario Roy <marioeroy at gmail.com>
> wrote:
> > > >
> > > > > Hi,
> > > > >
> > > > > What are the recommended arguments for folks using NVIDIA 3000
> series
> > > > > graphics and decoding AV1 media? I tried the same with VP9 media.
> > > > >
> > > > > The following was done using FFmpeg 5.1.
> > > > >
> > > > > ffmpeg -y -hwaccel vdpau -c:v av1_cuvid -i input_av1.mp4
> > > > > output.ts segfaults
> > > > > ffmpeg -y -hwaccel vdpau -c:v vp9_cuvid -i input_vp9.webm
> > > > > output.ts segfaults
> > > > >
> > > > > ffmpeg -y -hwaccel vdpau -i input_av1.mp4 output.ts decodes on
> the
> > >
> > > CPU
> > > > > ffmpeg -y -hwaccel vdpau -i input_vp9.webm output.ts decodes on
> the
> > >
> > > GPU
> > > > >
> > > > > ffmpeg -y -hwaccel nvdec -c:v av1_cuvid -i input_av1.mp4 output.ts
> > > > > ffmpeg -y -hwaccel nvdec -c:v vp9_cuvid -i input_vp9.webm output.ts
> > > > >
> > > > > ffmpeg -y -c:v av1_cuvid -i input_av1.mp4 output.ts
> > > > > ffmpeg -y -c:v vp9_cuvid -i input_vp9.webm output.ts
> > > > >
> > > > > Best,
> > > > > Mario
> > > > >
> > > > >
> > > >
> > > > _______________________________________________
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