one case has garbage when play the file after vpp framerate

[wangzj0601]

Test Env:
Platfrom: SKL
OS: CentOS 7.3.1611
Kernel version: 4.4.0
VPG Driver: 16.5.2.64009-ubit
Mediasdk: MediaServerStudioEssentials2017R3
FFMPEG: 0e9c48d (branch:intel_ffmpeg-3.4.1)
repo: https://github.com/Intel-FFmpeg-Plugin/Intel_FFmpeg_plugins.git

Reproduce Steps:

1. build the environment as above
2. ffmpeg -init_hw_device qsv=foo -filter_hw_device foo -hwaccel qsv -c:v h264_qsv -i /media/ffmpeg_stream_dcg//TallShip_8mbps_Echostar_12MbpsCBR.mp4 -vf vpp_qsv=framerate=60 -c:v h264_qsv -an -y /home/harddisk_sdb2/dcgm-ffmpeg-qsv-validation/output/VPP/framerate/vpp_1920x1080P_framerate30to60.mp4
3. playback the file vpp_1920x1080P_framerate30to60.mp4 and observe.