title: I can't use HW encoder of QSV by ffmpeg
body: <p>I would like to use to encode by Intel H/W encode QSV.</p>
  <blockquote>
  <p>Intel(R) Core(TM) i7-5650U CPU @ 2.20GHz</p>
  <p>lspci -nn -s 0:02.0
  00:02.0 VGA compatible controller [0300]: Intel Corporation Broadwell-U Integrated Graphics [8086:1626] (rev 09)</p>
  </blockquote>
  <p>I could install MediaServerStudioEssentials2017R2 and ffpemg.</p>
  <pre><code># vainfo | grep -v 'unknown'
  error: can't connect to X server!
  libva info: VA-API version 0.99.0
  libva info: va_getDriverName() returns 0
  libva info: User requested driver 'iHD'
  libva info: Trying to open /opt/intel/mediasdk/lib64/iHD_drv_video.so
  libva info: Found init function __vaDriverInit_0_32
  libva info: va_openDriver() returns 0
  vainfo: VA-API version: 0.99 (libva 1.67.0.pre1)
  vainfo: Driver version: 16.5.1.59511-ubit
  vainfo: Supported profile and entrypoints
        VAProfileH264ConstrainedBaseline: VAEntrypointVLD
        VAProfileH264ConstrainedBaseline: VAEntrypointEncSlice
        VAProfileH264Main               : VAEntrypointVLD
        VAProfileH264Main               : VAEntrypointEncSlice
        VAProfileH264High               : VAEntrypointVLD
        VAProfileH264High               : VAEntrypointEncSlice
        VAProfileMPEG2Simple            : VAEntrypointEncSlice
        VAProfileMPEG2Simple            : VAEntrypointVLD
        VAProfileMPEG2Main              : VAEntrypointEncSlice
        VAProfileMPEG2Main              : VAEntrypointVLD
        VAProfileVC1Advanced            : VAEntrypointVLD
        VAProfileVC1Main                : VAEntrypointVLD
        VAProfileVC1Simple              : VAEntrypointVLD
        VAProfileJPEGBaseline           : VAEntrypointVLD
        VAProfileJPEGBaseline           : VAEntrypointEncPicture
        VAProfileVP8Version0_3          : VAEntrypointEncSlice
        VAProfileVP8Version0_3          : VAEntrypointVLD
        VAProfileNone                   : VAEntrypointVideoProc
  </code></pre>
  <p>and</p>
  <pre><code># ffmpeg -codecs | grep qsv
  ffmpeg version N-86584-g4976a34 Copyright (c) 2000-2017 the FFmpeg developers
    built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-11)
    configuration: --enable-libmfx
    libavutil      55. 66.100 / 55. 66.100
    libavcodec     57. 99.100 / 57. 99.100
    libavformat    57. 73.100 / 57. 73.100
    libavdevice    57.  7.100 / 57.  7.100
    libavfilter     6. 94.100 /  6. 94.100
    libswscale      4.  7.101 /  4.  7.101
    libswresample   2.  8.100 /  2.  8.100
   DEV.LS h264                 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders: h264 h264_qsv h264_cuvid ) (encoders: h264_nvenc h264_qsv h264_vaapi nvenc nvenc_h264 )
   DEV.L. hevc                 H.265 / HEVC (High Efficiency Video Coding) (decoders: hevc hevc_qsv hevc_cuvid ) (encoders: nvenc_hevc hevc_nvenc hevc_qsv hevc_vaapi )
   DEV.L. mpeg2video           MPEG-2 video (decoders: mpeg2video mpegvideo mpeg2_qsv mpeg2_cuvid ) (encoders: mpeg2video mpeg2_qsv mpeg2_vaapi )
   D.V.L. vc1                  SMPTE VC-1 (decoders: vc1 vc1_qsv vc1_cuvid )
   DEV.L. vp8                  On2 VP8 (decoders: vp8 vp8_cuvid vp8_qsv ) (encoders: vp8_vaapi )
  </code></pre>
  <p>But, I tried to encode as below.</p>
  <pre><code># ffmpeg -i test.avi -c:v h264_qsv -b:v 2000k -r 30 -s 720x480 -acodec copy -look_ahead 0 qsv.mp4
  ・・・
  [h264_qsv @ 0x3139f40] No device available for encoder (device type qsv for codec h264_qsv).
  [h264_qsv @ 0x3139f40] Encoder will work with partial HW acceleration
  [h264_qsv @ 0x3139f40] Warning in encoder initialization: partial acceleration (4)
  ・・・
  </code></pre>
  <p>It seems like that the encoding is using by software. It's slow.
  How can I do by H/W encode? If you know it, let me know it.</p>
  <p>Bests,</p>