Recherche avancée

Sur d’autres sites (5340)

• Animate Windows desktop background using a timer in VB

  28 août 2017, par Mousa Alfhaily

  I’m working on code that should animate the desktop background using a timer and I achieved that using the code below, but I’n not planing to change it randomly to random wallpapers, so here is my problem, i’m using (ffmpeg) command-line to extract all the frames from a GIF image, then I’m running a timer with a low interval(100), to loop through all the frames and change the background using the User32.dll API, but the problem is that the animation is not very smooth as if you open it in the browser, and the program will be very slow during the animation, so I don’t know if there is another way to change the background without the lag, here is what i have done so far :

  Imports System.IO
  
  
  
  Public Class Form1
  
      Private Declare Auto Function SystemParametersInfo Lib "user32.dll" (ByVal X As Integer, ByVal Y As Integer, ByVal Z As String, ByVal W As Integer) As Integer
  
      Dim FrameX As Integer
  
  
  
      Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
  
          Timer1.Start()
  
      End Sub
  
  
  
      Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
  
          'If the frame is not exist then loop from the begenning with the frame 0.
  
          If Not File.Exists(Application.StartupPath & "\Frames\animation" & FrameX & ".png") Then
  
              FrameX = 0
  
          End If
  
          Try
  
              SystemParametersInfo(20, 0, Application.StartupPath & "\Frames\animation" & FrameX & ".png", 1 Or 2)
  
          Catch ex As Exception : End Try
  
  
  
          FrameX += 1
  
          Timer1.Start()
  
      End Sub
  
  End Class

• Artifacts after HEVC 10-bit encoding using NVENC

  18 juillet 2017, par Cryman

  Recently I purchased a brand new GPU - AORUS GeForce GTX 1080 Ti. I found out that it supports HEVC 10-bit encoding, so I wanted to give that a try. Unfortunately, after encoding I noticed some artifacts, which occur in dark scenes and last one frame of the video. You can see them on these screenshots :

  

  

  I was wondering if someone could help me figure out what might be the cause of these artifacts and how I can get rid of them.

  Here is the MI of the source video :

  ID                                       : 1
  
  Format                                   : AVC
  
  Format/Info                              : Advanced Video Codec
  
  Format profile                           : High@L4.1
  
  Format settings, CABAC                   : Yes
  
  Format settings, ReFrames                : 4 frames
  
  Codec ID                                 : V_MPEG4/ISO/AVC
  
  Duration                                 : 2 h 2 min
  
  Bit rate mode                            : Variable
  
  Bit rate                                 : 29.5 Mb/s
  
  Maximum bit rate                         : 37.0 Mb/s
  
  Width                                    : 1 920 pixels
  
  Height                                   : 1 080 pixels
  
  Display aspect ratio                     : 16:9
  
  Frame rate mode                          : Constant
  
  Frame rate                               : 23.976 (24000/1001) FPS
  
  Color space                              : YUV
  
  Chroma subsampling                       : 4:2:0
  
  Bit depth                                : 8 bits
  
  Scan type                                : Progressive
  
  Bits/(Pixel*Frame)                       : 0.593
  
  Stream size                              : 25.2 GiB (66%)
  
  Language                                 : English
  
  Default                                  : Yes
  
  Forced                                   : No

  And here is the MI of the encoded video :

  ID                                       : 1
  
  Format                                   : HEVC
  
  Format/Info                              : High Efficiency Video Coding
  
  Format profile                           : Main 10@L4@Main
  
  Codec ID                                 : V_MPEGH/ISO/HEVC
  
  Duration                                 : 2 h 2 min
  
  Bit rate                                 : 3 689 kb/s
  
  Width                                    : 1 920 pixels
  
  Height                                   : 800 pixels
  
  Display aspect ratio                     : 2.40:1
  
  Frame rate mode                          : Constant
  
  Frame rate                               : 23.976 (24000/1001) FPS
  
  Standard                                 : Component
  
  Color space                              : YUV
  
  Chroma subsampling                       : 4:2:0
  
  Bit depth                                : 10 bits
  
  Bits/(Pixel*Frame)                       : 0.100
  
  Stream size                              : 3.15 GiB (95%)
  
  Default                                  : Yes
  
  Forced                                   : No
  
  Color range                              : Limited

  The command I’m using for encoding :

  ffmpeg -hide_banner -i "" -map 0:v:0 -map_chapters -1 -map_metadata -1 -vf "crop=1920:800:0:140" -vcodec hevc_nvenc -pix_fmt p010le -preset hq -profile:v main10 -rc constqp -global_quality 21 -rc-lookahead 32 -g 240 -f matroska Video_CQP21_LAF32_GOP240.mkv

• ffmpeg progress is freezing frames when scene change

  19 août 2017, par Karol

  I’m capturing data from IP camera with RTSP protocol with ffmpeg with command :

  ffmpeg -rtsp_transport tcp -progress /media/kamip/stats.txt -i rtsp://192.168.1.220:554/live/h264/ch0 
  
  -c:v copy -c:a copy -strict 1 -map 0 -f segment -strftime 1 
  
  -segment_time 1800 /media/kamip/cam_%d_%m_%Y_%H_%M_%S.mkv

  I’m using this for 5 cameras. One is different type and it is in different location.
  Because ffmpeg does not support reconnect I’m writing status to /media/kamip/stats.txt file. In another script I’m parsing this output and every 30 seconds I’m checking if frame number changed, if yes - it is ok, if not, I’m restarting above command.

  The problem is only in the night. When is quite dark and suddenly lights on, for example when car is parking, the /media/kamip/stats.txt is showing the same frame number, so my script is recognizing this as a lost connection (video freeze)

  I tried "-strict 1" option and I think it is better (one false alarm per day instead of 10 per day), so I think this may be related to ffmpeg, not camera/video source, especially because the video is fine even frame number reported by ffmpeg is still the same. Also VLC does not have this kind of problem (but I cannot use it currently for this camera)

  I found that ffmpeg has build-in scene change detector, but it should works only when encoding video (I’m using "copy" option for audio and video) ?

  I’m thinking about different way of analyzing the video capturing, but this "-progress" in ffmpeg should works fine - and it is working fine for other cameras for few years).

  I also do not see any errors,
  when I encoded one cutted file with "-loglevel debug" I saw only information like below :

  [libx264 @ 0x25d77a0] scene cut at 174 Icost:2049115 Pcost:2006553 
  
  ratio:0.0208 bias:0.1387 gop:54 (imb:3186 pmb:168)

  ffmpeg in latest version

  ffmpeg version 3.3.3-1ubuntu1~16.04.york0 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609

  any help will be appreciated