Les articles publiés sur le site

• Create a Video file with Accord.video.ffmpeg and vb.net [on hold]

  11 août 2017, par ATsiri

  I am new in VB.NET Programming. I am trying to make an application that grabs my USB camera and then I can make a video file from it.

  I have searched a lot and found out that Accord.video.ffmpeg can do this job.

  I have managed to capture my USB camera but I am having a problem to make a video file and save it to my debug folder.

  Any ideas? How can I do it?

• How can I download a video with url beginning with blob:https://…

  11 août 2017, par iMax

  I would like to know if it is possible to download a video from a URL beginning with blob:

  blob:https://www.xyz123…
  

  i would prefer a terminal solution (ffmpeg?, youtube-dl?). but i have not found anything on the world wide web.

  Again: I have the url of the video stream, which looks like the above. How can I download the complete video?

  Update

  Ok. I now found a webpage which allowed me to download the video file I wanted: https://video-download.online/

  But I am still wondering if there is a Terminal solution for downloading video with blob-URL (like in arte mediathek [ example arte ] or in zdf mediathek [ example zdf ]).

  Does nobody know how to do it?

• Using FFMpeg Video Frames From directories

  11 août 2017, par Peter Friedlander

  I have hundreds of folders containing video, audio, images.. which I need to create video thumbs foreach 10 seconds of video of every video file found (mp4/avi/mov/3gp) and placed in one location /thumbs/.

  I have this, which I've been trying to figure out for days.

  find . -exec ffmpeg -i {} -vf fps=1/8 {}.png \;
  

  or

  find /Users/media/Desktop/videoframes/input/  -regex ".*\.\(mp4\)" -print0 | while read -d $'\0' file;  do  ffmpeg -i $file -vf fps=1/8 ${file}%d.png done
  

  I know little about the syntax but want to learn more but Im stumped.

  Thanks!

• How do steps for make FFMPEG

  11 août 2017, par mobina varmazyar

  I do step 1 to step 6. I am sure that I take NDK and ffmepeg source in valid address but when I execute

  ./build_android.sh
  

  in the terminal the following lines will be shown:

  @mv103 telegram
  

  Can send for me libraries whose can successfully did step 1 to 6 ?

  /build_android.sh: line 8: --prefix=/root/桌面/rajabi/android-ndk-
  r12b/sources/ffmpeg-3.3.3/android/arm: No such file or directory
  ./build_android.sh: line 9: --enable-shared: command not found
  

• h264_omx = mostly black videos, libx264 too slow, audio slows everything down

  11 août 2017, par Brendan Grant

  I'm attempting to port a live tv transcoding app from Windows (on .net core) to work on a Raspberry Pi 3.

  Under the hood I uses ffmpeg to take in an mpeg2 stream from a local networked tv tuner and spit out a local HLS stream which is exposed via a custom http server.

  FFmpeg on Linux is configured for build as following:

  sudo ./configure --arch=armhf --target-os=linux --enable-gpl --enable-libx264 --enable-nonfree --enable-mmal --enable-omx --enable-omx-rpi
  

  Seeing perf issues early on, I tried to boil it down to a simpler form and started using a VOB from a DVD (also mpeg2), take the following example:

  ffmpeg -i VTS_01_2.VOB -c:a aac -c:v h264_omx -b:v 256k -hls_time 3 -hls_wrap 30 "/media/usb1/foo.m3u8"
  

  Within a matter of seconds, this drops to not only under 30 FPS, but down to the low teens.

  The following runs plenty fast, and is able to keep up when pointed to the tv stream... only all but the first ts file will end up being black (but with audio)... which it turns out the previous line also suffers from:

  ffmpeg -i VTS_01_2.VOB -c:a copy -c:v h264_omx -b:v 256k -hls_time 3 -hls_wrap 30 "/media/usb1/foo.m3u8"
  

  Aside from the oddity of my choice of audio codecs (ie accepting what is already there vs choosing something else) would so slow down the stream, I also discovered that in order to have visible video... I have to go without hardware assistance.

  ffmpeg -i VTS_01_2.VOB -c:a aac -c:v libx264 -b:v 256k -hls_time 3 -hls_wrap 30 "/media/usb1/foo.m3u8"
  

  and

  ffmpeg -i VTS_01_2.VOB -c:a copy -c:v libx264 -b:v 256k -hls_time 3 -hls_wrap 30 "/media/usb1/foo.m3u8"
  

  both turn out video which shows up... and with good audio, except both are too slow in terms of FPS to be able to keep up with a live tv stream.

  Is there something I am missing here to be able to get ffmpeg to be able to handle turning an mpeg2 stream into an h.264 one... and have the resulting files have video?

  To save space here, I've put the console logs on pastebin.

  h264_omx: https://pastebin.com/GK3zN4aB libx264: https://pastebin.com/uEdCwk47

  As I think about it more, the "[mpegts @ 0x2fe0be0] H.264 bitstream error, startcode missing, size 082 drop=0 speed=3.07x" error may be related, but when looking at a longer session we do not see them as regular (as I would think) to obliterate the entire video stream on later files whose sizes are inline with the first: https://pastebin.com/J1EzTqgK