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• recording live stream video from tv card using ffmpeg at window [on hold]

  6 décembre 2013, par user2688423

  I want to record live stream every 1 second from tv card(tv signal) using ffmpeg in window.

  first of all, to record live video from tv card, I tried below.

  1. First I tried this.

  ffmpeg -list_devices true -f dshow -i dummy

  then the result is

  " [dshow @ 000000000024e6fe0] DirectShow video devices
  [dshow @000000000024e6fe0] "SKYTV HD USB Maxx Video Capture"
  [dshow @
  000000000024e6fe0] DirectShow audio devices
  [dshow @
  000000000024e6fe0] "Analog Audio In(SKYTV HD USB Ma" "

  so I tried

  ffmpeg -f dshow -i video="SKYTV HD USB Maxx Video Capture" -r 20
  -threads 0 D ://test.mkv

  But it didn't work. the Error message is

  "[dshow@000000000034d920] Could not run filter
  video=SKYTV HD USB
  Maxx Video Capture : Input/output error"

  I use the device called 'SKYTV HD USB Maxx Video Capture' for getting tv signal(TV card).

  1. The First way deosn't work, I tried different way.

  ffmpeg -y -f vfwcap -i list

  then the result is
  "

  [dshow @ 00000000003fd760] Driver 0

  [dshow @ 00000000003fd760] Microsoft WDM Image Capture (Win32)
  [dshow @ 00000000003fd760] Version : 6.1.7601.17514 list : Input/output error

  "

  so I tried

  ffmpeg -y -f vfwcap -r 25 -i 0 D ://out.mp4

  then, there is some out.mp4 file in D drive but the file is nothing.
  (I think it is not TV signal)

  what should i do to record live video every 1 second from tv card(tv signal) using ffmpeg in window ? And How can I set channel at tvcard(Because I want to get tv signal, there are many channels).

  Please help..!

• hwcontext_drm : make dependency on Linux kernel headers optional

  30 décembre 2020, par Lynne

  hwcontext_drm : make dependency on Linux kernel headers optional
  This was introduced in version 4.6. And may not exist all without an
  
  optional package. So to prevent a hard dependency on needing the Linux
  
  kernel headers to compile, make this optional.
  Also ignore the status of the ioctl, since it may fail on older kernels
  
  which don't support it. It's okay to ignore as its not fatal and any
  
  serious errors will be caught later by the mmap call.
  

  • [DH] configure
  • [DH] libavutil/hwcontext_drm.c

• Using FFMPEG I get an error when trying to insert a fade after about 35 mins in a long video - is this possible ?

  8 avril 2019, par Matt Gardiner

  I have a source video that is an hour long from which I want to extract a couple of minutes towards the end and add a video fade in at the start of the cropped section.

  Using FFMPEG, I’m specifying the following command :

  ffmpeg -i MyLongVideo.mp4 -q:v 0 -y -ss 00:50:00.000 -to 00:52:00.000 -vf "fade=t=in:st=3000.0:d=1.0, scale=iw*min(1280/iw\,720/ih):ih*min(1280/iw\,720/ih),pad=1280:720:(1280-iw)/2:(720-ih)/2" ./testoutput.ts

  This is intended to crop from the source video from 50:00.000 to 52:00.00 and fade in from the 50th minute for 0.5 seconds (so at 3000 seconds in - st=3000.0).

  This command that we build programmatically, works on shorter videos or when you crop from before about 35 minutes. For this longer video though I get an error that says :

  [fade @ 0000025399981e80] Value 3000.000000 for parameter 'st' out of range [0 - 2147.48]

  The 2147.48 is around the 35 minutes in seconds which explains why this command works for shorter videos or on crops earlier than 35 minutes.

  I’ve seen a number of other issues with FFMPEG talking about this ’magic’ 2147.48 number with parameter values. Is this some sort of hard limit ?

  Is there a way to do what I want to do ? I could do this in two passes - extract the section of video and then add the fade, but I’d rather do it in one command if possible - and it works for shorter/earlier crops.