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• lower latency LAN video streaming to Android ? [closed]

  8 janvier 2020, par LargeMoneyBanks

  I am trying to stream desktop video from windows to an Android device on the same network, but seeing huge latency even streaming windows to windows.

  Technically streaming to a unity game using this asset that doesnt support udp but DOES support HTTPS,HTTP,HLS,RTSP,RTMP. https://assetstore.unity.com/packages/tools/video/ump-android-ios-56044

  With some help from a friend I am using ffmpeg for capture, encoding, and streaming with this command :

  .\ffmpeg -threads 8 -f gdigrab -framerate 60 -i desktop -c:v libx264 -refs 3 -g 60 -loglevel debug -pix_fmt yuv420p -slices 8 -an -preset ultrafast -tune zerolatency -f mpegts -listen 1 tcp://0.0.0.0:1234

  Latency is still around 4 seconds even playing the stream on the same PC as hosting, and fiddling with the network cache. Lowering resolution, fps etc doesn’t change latency. This is my first endeavor into optimizing any kind of streaming so I am a little lost. Anyone know what I might be doing wrong or how I can get to at least under 1 second ?

  Thank you !

• ffmpeg convert variable framerate .webm to constant framerate video

  4 novembre 2019, par Dashadower

  I have a .webm file of a recording of a game at 16fps. However, upon trying to process the video with OpenCV, it seems the video is recorded with a variable framerate, so when I try to use OpenCV to get a frame every second by getting the every 16th frame, it won’t work since the video stream will end prematurely.

  Therefore, I’m trying to convert a variable-frame .webm video, which claims it has a framerate of 16 fps, to a video with a constant frame, so I can extract one frame for every second. I’ve tried the following ffmpeg command from https://ffmpeg.zeranoe.com/forum/viewtopic.php?t=5518 :

  ffmpeg -i input.webm -c:v copy -b:v copy -r 16 output.webm

  However, the following error will occur :

  [NULL @ 00000272ccbc0c40] [Eval @ 000000bc11bfe2f0] Undefined constant or missing '(' in 'copy'
  
  [NULL @ 00000272ccbc0c40] Unable to parse option value "copy"
  
  [NULL @ 00000272ccbc0c40] Error setting option b to value copy.
  
  
  
  Error setting up codec context options.

  Here’s is the code I’m trying to use to process a frame every second :

  video = cv2.VideoCapture(test_mp4_vod_path)
  
  print("Opened ", test_mp4_vod_path)
  
  print("Processing MP4 frame by frame")
  
  
  
  # forward over to the frames you want to start reading from.
  
  # manually set this, fps * time in seconds you wanna start from
  
  video.set(1, 0)
  
  success, frame = video.read()
  
  #fps = int(video.get(cv2.CAP_PROP_FPS))  # this will return 0!
  
  fps = 16  # hardcode fps
  
  total_frame_count = int(video.get(cv2.CAP_PROP_FRAME_COUNT))
  
  print("Loading video %d seconds long with FPS %d and total frame count %d " % (total_frame_count/fps, fps, total_frame_count))
  
  
  
  count = 1
  
  while video.isOpened():
  
      success, frame = video.read()
  
      if not success:
  
          break
  
  
  
      if count % fps == 0:
  
          print("%dth frame is %d seconds on video"%(count, count/fps))
  
      count += 1

  The code will finish before it gets near the end of the video, since the video isn’t at a constant FPS.
  How can I convert a variable-FPS video to a constant FPS video ?

• ffmpeg concatenate two videos, unexpectedly changes the first second(s) of 2nd video

  29 juin 2019, par Roy

  I used ffmpeg to concatenate two videos of my game play recordings. I wrote a list.txt file which lists the two files :

  list.txt:
  
  file 2019~06~28_~_Game_1_~_Part_2.mp4
  
  file 2019~06~28_~_Game_1_~_Part_3.mp4

  I then run ffmpeg to concat them :

  ffmpeg -safe 0 -f concat -i list.txt -c copy "output.mp4"

  However, the resulting video seems to be skipping frames (or going through them really quickly) at the first second(s) of the second video, causing the perception of the motion suddenly fast-forwarded.

  The two videos were recorded by the same game video recorder "GeForce Experience" in one game session. They should match smoothly when concatenated.

  Here is the output of ffmpeg :

  ffmpeg version 3.4.1 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with gcc 7.2.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth --enable-libmfx
  
    libavutil      55. 78.100 / 55. 78.100
  
    libavcodec     57.107.100 / 57.107.100
  
    libavformat    57. 83.100 / 57. 83.100
  
    libavdevice    57. 10.100 / 57. 10.100
  
    libavfilter     6.107.100 /  6.107.100
  
    libswscale      4.  8.100 /  4.  8.100
  
    libswresample   2.  9.100 /  2.  9.100
  
    libpostproc    54.  7.100 / 54.  7.100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000001600bbdb5e0] Auto-inserting h264_mp4toannexb bitstream filter
  
  Input #0, concat, from 'list.txt':
  
    Duration: N/A, start: 0.000000, bitrate: 24674 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, smpte170m/smpte170m/bt470m), 1920x1080 [SAR 1:1 DAR 16:9], 24479 kb/s, 59.69 fps, 60 tbr, 90k tbn, 120 tbc
  
      Metadata:
  
        creation_time   : 2019-06-29T04:43:18.000000Z
  
        handler_name    : VideoHandle
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 195 kb/s
  
      Metadata:
  
        creation_time   : 2019-06-29T04:43:18.000000Z
  
        handler_name    : SoundHandle
  
  File 'output.mp4' already exists. Overwrite ? [y/N] y
  
  Output #0, mp4, to 'output.mp4':
  
    Metadata:
  
      encoder         : Lavf57.83.100
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, smpte170m/smpte170m/bt470m), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 24479 kb/s, 59.69 fps, 60 tbr, 90k tbn, 90k tbc
  
      Metadata:
  
        creation_time   : 2019-06-29T04:43:18.000000Z
  
        handler_name    : VideoHandle
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 195 kb/s
  
      Metadata:
  
        creation_time   : 2019-06-29T04:43:18.000000Z
  
        handler_name    : SoundHandle
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
    Stream #0:1 -> #0:1 (copy)
  
  Press [q] to stop, [?] for help
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000001600bbdb5e0] Auto-inserting h264_mp4toannexb bitstream filter
  
  frame= 7405 fps=0.0 q=-1.0 Lsize=  221175kB time=00:02:03.63 bitrate=14655.4kbits/s speed= 157x
  
  video:218137kB audio:2862kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.079741%

  In particular, I don’t know what does "Auto-inserting h254_mp4toannexb bitstream filter" mean. Did this caused the unexpected change ?