on Linux i am trying to encode file to H€VC using hardware acceleration. Successful attempt is:

```
ffmpeg -v verbose -hwaccel vaapi -vaapi_device /dev/dri/renderD128 -i '/path/file.mkv' -vcodec libx265 -crf 28 '/path/file.mp4'

```

but it is slow like 30fps, "`ffmpeg -codecs|grep 265`" shows:
(encoders: libx265 nvenc\_hevc hevc\_amf hevc\_nvenc hevc\_qsv hevc\_v4l2m2m hevc\_vaapi )

so i have tried hevc\_vaapi:

```
ffmpeg -v verbose -hwaccel vaapi -vaapi_device /dev/dri/renderD128 -i '/path/file.mkv' -vcodec hevc_vaapi -crf 28 '/path/file.mp4'

```

but it fails:

```
Impossible to convert between the formats supported by the filter 'Parsed_null_0' and the filter 'auto_scaler_0'
Error reinitializing filters!
Failed to inject frame into filter network: Function not implemented
Error while processing the decoded data for stream #0:0
[AVIOContext @ 0x55d831121340] Statistics: 0 seeks, 0 writeouts
[aac @ 0x55d831142a00] Qavg: 30414.529
[aac @ 0x55d831142a00] 2 frames left in the queue on closing
[AVIOContext @ 0x55d831109ec0] Statistics: 65536 bytes read, 0 seeks
Conversion failed!

```

$ ffmpeg -hwaccels shows "

```
Hardware acceleration methods:
vdpau
cuda
vaapi
qsv
drm

```

"

$ vaapi [shows this](https://bin.disroot.org/?63599363da4aa168#3ArZXE42YiANP4cevpZUdPYo4Vt95CqysapLpvNmrGbq)
(seems like va-api is there, mesa driver)

$ ls /dev/dri/\*

> 
> /dev/dri/card0 /dev/dri/renderD128
> 
> 
> /dev/dri/by-path:
> 
> 
> pci-0000:0a:00.0-card pci-0000:0a:00.0-render
> 
> 
> 

What do you think about this error or how would you proceed to discover which ffmpeg parameters to use for HW H€VC accelerated?

Update: i think that the "-hwaccel vaapi" may be redundant parameter