Hi,
perhaps this helps.
I tried to play directly with gstreamer (gst-launch-0.10 -v playbin ) a video.
Result, with vaapi only audio but no video output.

Here command line  output:

Leitung wird auf PAUSIERT gesetzt ...
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = video/quicktime, variant=(string)iso
Leitung läuft vor …
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQTDemux:qtdemux0.GstPad:sink: caps = video/quicktime, variant=(string)iso
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0.GstPad:sink: caps = audio/mpeg, mpegversion=(int)4, framed=(boolean)true, stream-format=(string)raw, level=(string)2, base-profile=(string)lc, profile=(string)lc, codec_data=(buffer)1210, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue1.GstPad:sink: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, level=(string)3.1, profile=(string)high, codec_data=(buffer)0164001ffde1001a6764001fac248805005bb011000003000100000300308f1832a001000568ee32c8b0, width=(int)1280, height=(int)720, framerate=(fraction)24/1, pixel-aspect-ratio=(fraction)1/1
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue1.GstPad:sink: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, level=(string)3.1, profile=(string)high, codec_data=(buffer)0164001ffde1001a6764001fac248805005bb011000003000100000300308f1832a001000568ee32c8b0, width=(int)1280, height=(int)720, framerate=(fraction)24/1, pixel-aspect-ratio=(fraction)1/1
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue1.GstPad:src: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, level=(string)3.1, profile=(string)high, codec_data=(buffer)0164001ffde1001a6764001fac248805005bb011000003000100000300308f1832a001000568ee32c8b0, width=(int)1280, height=(int)720, framerate=(fraction)24/1, pixel-aspect-ratio=(fraction)1/1
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstH264Parse:h264parse0.GstPad:sink: caps = video/x-h264, stream-format=(string)avc, alignment=(string)au, level=(string)3.1, profile=(string)high, codec_data=(buffer)0164001ffde1001a6764001fac248805005bb011000003000100000300308f1832a001000568ee32c8b0, width=(int)1280, height=(int)720, framerate=(fraction)24/1, pixel-aspect-ratio=(fraction)1/1
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstAacParse:aacparse0.GstPad:sink: caps = audio/mpeg, mpegversion=(int)4, framed=(boolean)true, stream-format=(string)raw, level=(string)2, base-profile=(string)lc, profile=(string)lc, codec_data=(buffer)1210, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstFaad:faad0.GstPad:sink: caps = audio/mpeg, mpegversion=(int)4, framed=(boolean)true, stream-format=(string)raw, level=(string)2, base-profile=(string)lc, profile=(string)lc, codec_data=(buffer)1210, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstFaad:faad0.GstPad:src: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstStreamSelector:selector_audio_src0.GstPlaybinSelectorPad:sink0: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstDecodeBin:decodebin0.GstGhostPad:src0.GstProxyPad:proxypad1: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstStreamSelector:selector_audio_src0.GstPad:src: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstQueue:preroll_audio_src0.GstPad:sink: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
libva: VA-API version 0.32.0
libva: va_getDriverName() returns 0
libva: Trying to open /usr/lib/dri/i965_drv_video.so
libva: va_openDriver() returns 0
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstH264Parse:h264parse0.GstPad:src: caps = video/x-h264, stream-format=(string)byte-stream, alignment=(string)au, level=(string)3.1, profile=(string)high, width=(int)1280, height=(int)720, framerate=(fraction)24/1, pixel-aspect-ratio=(fraction)1/1, parsed=(boolean)true
** Message: don't know how to handle video/x-surface, width=(int)1280, height=(int)720, framerate=(fraction)24/1, pixel-aspect-ratio=(fraction)1/1, type=(string)vaapi, opengl=(boolean)false
Fehlendes Element: video/x-surface-Decoder
/GstPlayBin:playbin0/GstStreamSelector:selector_audio_src0: active-pad = (GstPlaybinSelectorPad) sink0
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstVaapiDecode:vaapidecode0.GstPad:src: caps = video/x-surface, width=(int)1280, height=(int)720, framerate=(fraction)24/1, pixel-aspect-ratio=(fraction)1/1, type=(string)vaapi, opengl=(boolean)false
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstVaapiDecode:vaapidecode0.GstPad:sink: caps = video/x-h264, stream-format=(string)byte-stream, alignment=(string)au, level=(string)3.1, profile=(string)high, width=(int)1280, height=(int)720, framerate=(fraction)24/1, pixel-aspect-ratio=(fraction)1/1, parsed=(boolean)true
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstVaapiDecode:vaapidecode0.GstPad:sink: caps = video/x-h264, stream-format=(string)byte-stream, alignment=(string)au, level=(string)3.1, profile=(string)high, width=(int)1280, height=(int)720, framerate=(fraction)24/1, pixel-aspect-ratio=(fraction)1/1, parsed=(boolean)true
/GstPlayBin:playbin0/GstBin:abin/GstAudioConvert:aconv.GstPad:src: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstBin:abin/GstAudioConvert:aconv.GstPad:sink: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstBin:abin.GstGhostPad:sink: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstBin:abin.GstGhostPad:sink.GstProxyPad:proxypad3: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstBin:abin/GstAudioResample:aresample.GstPad:src: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstBin:abin/GstAudioResample:aresample.GstPad:sink: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstBin:abin/GstVolume:volume.GstPad:src: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstBin:abin/GstVolume:volume.GstPad:sink: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstBin:abin/GstAutoAudioSink:audiosink/GstPulseSink:audiosink-actual-sink-pulse.GstPad:sink: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstBin:abin/GstAutoAudioSink:audiosink.GstGhostPad:sink: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPlayBin:playbin0/GstBin:abin/GstAutoAudioSink:audiosink.GstGhostPad:sink.GstProxyPad:proxypad2: caps = audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
Leitung ist vorgelaufen …
Leitung wird auf ABSPIELEN gesetzt ...
New clock: GstPulseSinkClock
/GstPlayBin:playbin0/GstBin:abin/GstAutoAudioSink:audiosink/GstPulseSink:audiosink-actual-sink-pulse: volume = 1,000000
/GstPlayBin:playbin0/GstBin:abin/GstAutoAudioSink:audiosink/GstPulseSink:audiosink-actual-sink-pulse: mute = FALSE
/GstPlayBin:playbin0/GstBin:abin/GstAutoAudioSink:audiosink/GstPulseSink:audiosink-actual-sink-pulse: volume = 1,000000
/GstPlayBin:playbin0/GstBin:abin/GstAutoAudioSink:audiosink/GstPulseSink:audiosink-actual-sink-pulse: mute = FALSE
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0: max-size-bytes = 17004
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0: max-size-bytes = 34130
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0: max-size-bytes = 68376
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0: max-size-bytes = 137042
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0: max-size-bytes = 274232
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0: max-size-bytes = 548894
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0: max-size-bytes = 1098200
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0: max-size-bytes = 2146827
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0: max-size-bytes = 3195707
/GstPlayBin:playbin0/GstDecodeBin:decodebin0/GstQueue:queue0: max-size-bytes = 4244567