[Spice-devel] playbin can't detect vaapi decoder correctly when playing a video stream.

Mon Aug 6 10:33:16 UTC 2018

Hi,

On Sat, Aug 04, 2018 at 10:37:00PM +0800, Qiu Wenbo wrote:
> Thank you for the reply. I am pretty sure I have a working
> vaapih264dec element since I can setup a pipeline manually to
> play a H.264 video. Also, the output of remote-viewer with
> --spice-debug is almost the same as yours(vaapidecodebin,
> vaapih264dec).

Right

> >> Couldn't set vaapidecodebin0 to PAUSEDElement
> >> vaapidecode_h264-0 does not
> accept caps
> 
> The last line of the log says vaapidecode_h264 dose not accept
> caps. Is there any possibility that my hardware(intel i5-6500)
> can't decode some H.264 stream with certain parameter (as the
> default x264enc setup generate) since I can confirm playbin is
> using vaapih264dec when I manually change the encoder of
> spice-server from x264 to vaapih264enc (still has a jamed
> pipeline). Can you provides some hardware known to work?

For the encoding, I have no clue. I haven't tested vaapih264enc
at all. If you make it work, patches are very welcome by the way
for that.

To debug your issue with Caps, you could set GST_DEBUG=4 (or 5
even) and look into what specific issues the pipeline had with
the Caps. Most of times we can workaround it in the client by
converting e.g pixel format, but at cost of cpu usage but in
case you make it work with vaapih264enc you can improve the
pipeline to reduce cpu usage later.

Cheers,

> On Fri, Aug 3, 2018 at 5:03 PM, Victor Toso <victortoso at redhat.com> wrote:
> > Hi,
> > 
> > On Fri, Aug 03, 2018 at 11:20:52AM +0800, Qiu Wenbo wrote:
> > >  I'm trying to turn on streaming video with H.264 codec
> > >  manually. I have noticed spice-gtk will use playbin to decode
> > >  the video stream with recent gstreamer.
> > 
> > Yes
> > 
> > >  However,  playbin tends to use software decoder (avdec_h264) on
> > >  my box (latest Archlinux running on an Intel i5-6500 PC with
> > >  gstreamer-vaapi). When I remove gstreamer-libav, gstreamer
> > >  complains like this and refuse to setup pipeline:
> > 
> > What is the output of
> > $ gst-inspect-1.0 | grep -i vaapi
> > 
> > Note that with --spice-debug enabled you should be seeing
> > something like
> > 
> >  | Spice-DEBUG: 10:52:22.453: channel-display-gst.c:696:
> >  | gstvideo_debug_available_decoders: From  15 video decoder elements,
> >  | 1 can handle caps image/jpeg: jpegdec
> > 
> >  | Spice-DEBUG: 10:52:22.453: channel-display-gst.c:696:
> >  | gstvideo_debug_available_decoders: From  15 video decoder elements,
> >  | 2 can handle caps video/x-vp8: vaapidecodebin, vp8dec
> > 
> >  | Spice-DEBUG: 10:52:22.453: channel-display-gst.c:696:
> >  | gstvideo_debug_available_decoders: From  15 video decoder elements,
> >  | 1 can handle caps video/x-h264: vaapidecodebin
> > 
> >  | Spice-DEBUG: 10:52:22.453: channel-display-gst.c:696:
> >  | gstvideo_debug_available_decoders: From  15 video decoder elements,
> >  | 2 can handle caps video/x-vp9: vaapidecodebin, vp9dec
> > 
> > This debug info is similar to running gst-inspect-1.0 and finding
> > the decoder elements per codec supported in spice-protocol
> > 
> > >  0:00:00.221423602 4816 0x7f24e40454a0 ERROR h264parse
> > >  gsth264parse.c:2588:gst_h264_parse_set_caps: video/x-h264 caps
> > > without
> > >  codec_data or stream-format
> > >  0:00:00.221548091 4816 0x7f24e40454a0 ERROR h264parse
> > >  gsth264parse.c:2588:gst_h264_parse_set_caps: video/x-h264 caps
> > > without
> > >  codec_data or stream-format
> > 
> > stream-format is not needed to play the stream and we lack a
> > way to set this info reliably in the procotol (the host is
> > hardcded to stream with byte-stream but could change, etc)
> > 
> > See
> > https://gitlab.freedesktop.org/spice/spice-gtk/commit/c9129ed202b00f4
> > 
> > >  0:00:00.517686292 4816 0x7f24e40454a0 WARN decodebin
> > >  gstdecodebin2.c:2514:connect_pad:<decodebin0> Couldn't set
> > > vaapidecodebin0
> > >  to PAUSED
> > >  0:00:00.518742010 4816 0x7f24e40454a0 WARN decodebin
> > >  gstdecodebin2.c:2339:connect_pad:<decodebin0> Element
> > > vaapidecode_h264-0
> > >  does not accept caps
> > >  0:00:00.518908940 4816 0x7f24e40454a0 WARN uridecodebin
> > >  gsturidecodebin.c:921:unknown_type_cb:<uridecodebin0> warning: No
> > > decoder
> > >  available for type 'video/x-h264, pixel-aspect-ratio=(fraction)1/1,
> > >  width=(int)1920, height=(int)1080, framerate=(fraction)30/1,
> > >  interlace-mode=(string)progressive, chroma-format=(string)4:4:4,
> > >  bit-depth-luma=(uint)8, bit-depth-chroma=(uint)8,
> > > parsed=(boolean)true,
> > >  stream-format=(string)avc, alignment=(string)au,
> > > profile=(string)high-4:4:4,
> > >  level=(string)5, codec_data=(buffer)01f40032ffe1001e67f400329184680780227e27016a02020280000003008000001e478c195001000468ce3192'.
> > >  0:00:00.518933285 4816 0x7f24e40454a0 WARN decodebin
> > >  gstdecodebin2.c:4640:gst_decode_bin_expose:<decodebin0> error: no
> > > suitable
> > >  plugins found:
> > >  Couldn't set vaapidecodebin0 to PAUSEDElement vaapidecode_h264-0
> > > does not
> > >  accept caps
> > 
> > "No decoder available" and "No plugins found", that's why I asked
> > above questions. Besides having gstreamer1-vaapi, you need
> > suitable drivers to make vaapi work
> > 
> > >  0:00:00.518951522 4816 0x7f24e40454a0 WARN uridecodebin
> > >  gsturidecodebin.c:988:no_more_pads_full:<uridecodebin0> error: no
> > > suitable
> > >  plugins found:
> > >  gstdecodebin2.c(4640): gst_decode_bin_expose ():
> > > /GstPlayBin:playbin/GstURIDecodeBin:uridecodebin0/GstDecodeBin:decodebin0:
> > >  no suitable plugins found:
> > >  Couldn't set vaapidecodebin0 to PAUSEDElement vaapidecode_h264-0
> > > does not
> > >  accept caps
> > > 
> > >  However, after install gstreamer-libav, the log shows playbin is
> > > using
> > >  avdec_h264. Also, I can confirm playbin is using vaapih264dec when I
> > >  manually change the encoder of spice-server from x264 to
> > > vaapih264enc.
> > 
> > Cheers,
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