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• Solution for VB6 to broadcast Webcam

  14 septembre 2018, par vantrung -cuncon

  Sorry, I know VB6 is decades ago, but I’m in a situation that I have to use VB6 to deliver live webcam stream beetween 2 PC in Server - Client Model program. Vb6-code holds the connection then I have no choice but to transfer all data via that connection.

  I’ve tried weeks for this, uncountable approaches but went to nowhere.
  My efforts focused on 3 major approaches :

  1/ Use ffmpeg to record live webcam as ".avi" file on hard disk, transfer parts of file to other end & play it. But I’ve stucked with a media-player that can play a "being written" avi file.

  Windows Media Player control told me "file already in use..." & VLC Plugin can’t even be added to VB6 (axvlc.dll).

  2/ Use ffmpeg to save live webcam as avi file, transfer each bit of that file to the other end, then in other end, extract 24 images / second from the avi to display continously in a picture box.
  This approach is ok except that my hard disk get fulled of images in a time of wink and my program get very slow before hanging.

  3/ Use ffmpeg to stream the live webcam to a rtp-port like this :

  ffmpeg -f dshow -i video="Lenovo EasyCamera" -vcodec mpeg2video -pix_fmt yuv422p -f rtp -an rtp://224.1.2.3:8191

  I’ve successfully watch the stream in VLC, but VLC(axvlc.dll) refused to be integrated into ancient VB6. And more important, I don’t know how to redirect/reroute the rtp stream to other PC with VB6.

  Any one please light me up ? (Any 3rd party component is welcomed)

• Why won't Apple players play this ffmpeg-generated video ? [duplicate]

  3 octobre 2018, par Giuseppe

  This question already has an answer here :

  • ffmpeg PNG to mp4 - Black screen
    
    1 answer
    

  I generated a short mp4 from a stack of PNG images, with no audio, like so :

  ffmpeg -r 24 -i t-%03d.png -r 24 -c:v libx264 test.mp4

  On my MacBook, the resulting video plays just fine with VLC or Chrome. With iTunes or Final Cut Pro, on the other hand, the progress bar moves as if playing was in progress, but the screen is blank. Finally, Safari and QuickTime complain that the format is invalid.

  Here is ffprobe’s output :

  ffprobe version 4.0.2 Copyright (c) 2007-2018 the FFmpeg developers
  
    built with Apple LLVM version 9.1.0 (clang-902.0.39.2)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.0.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-libmp3lame --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
  
    libavutil      56. 14.100 / 56. 14.100
  
    libavcodec     58. 18.100 / 58. 18.100
  
    libavformat    58. 12.100 / 58. 12.100
  
    libavdevice    58.  3.100 / 58.  3.100
  
    libavfilter     7. 16.100 /  7. 16.100
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  1.100 /  5.  1.100
  
    libswresample   3.  1.100 /  3.  1.100
  
    libpostproc    55.  1.100 / 55.  1.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf58.12.100
  
    Duration: 00:00:20.17, start: 0.000000, bitrate: 3918 kb/s
  
      Stream #0:0(und): Video: h264 (High 4:4:4 Predictive) (avc1 / 0x31637661), yuvj444p(pc), 1600x1200 [SAR 1:1 DAR 4:3], 3916 kb/s, 24 fps, 24 tbr, 12288 tbn, 48 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler

• Cannot Play Video Output of Libavcodec (ffmpeg) Encoding Example

  29 octobre 2019, par user3707763

  From FFMPEG’s GitHub, I use the encode_video.c to generate a 1 second video. Here is the example in question : https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/encode_video.c

  I compile with : gcc -Wall -o ffencode encode_video.c -lavcodec -lavutil -lz -lm

  Clean compile, zero warnings.

  I test the program by running : ./ffencode video.mp4 libx264

  Lots of stats printed out (expected based on source code) as well as ffmpeg logs, but ultimately no errors or warnings.

  However, then the generated output video.mp4, can only be played by ffplay, and VLC Player (as well as Google Chrome) fail to play the video.

  Playing it via vlc command line actually prints :

  [00007ffd3550fec0] main libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface.
  
  TagLib: MP4: Invalid atom size
  
  TagLib: MP4: Invalid atom size
  
  TagLib: MP4: Invalid atom size

  Looking at ffprobe output, the bitrate and duration fields are empty :

  Input #0, h264, from 'video.mp4':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: h264 (High), yuv420p(progressive), 352x288, 25 fps, 25 tbr, 1200k tbn, 50 tbc

  I am using ffmpeg 4.1 with the following configuration :

  ffprobe version 4.1 Copyright (c) 2007-2018 the FFmpeg developers
  
    built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gpl --enable-libmp3lame --enable-libopus --enable-libsnappy --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-opencl --enable-videotoolbox
  
    libavutil      56. 22.100 / 56. 22.100
  
    libavcodec     58. 35.100 / 58. 35.100
  
    libavformat    58. 20.100 / 58. 20.100
  
    libavdevice    58.  5.100 / 58.  5.100
  
    libavfilter     7. 40.101 /  7. 40.101
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100

  Any ideas how to fix this ? It is pretty surprising to see an API’s official example to be lacking such basic information.