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• Adobe connect video : FLV to MP4 (export, convert)

  4 mai 2022, par Guillaume Chevalier

  I would like to convert an adobe connect video from .flv in the downloaded zip to .mp4. I have already done the steps explained in this question and answer, however I get .flv files organised like this inside the .zip :

  



  

  



  Moreover, I know that ffmpeg can merge video and sound files together as well as concatenating resulting clips directly from the command-line which could be quite useful : https://www.labnol.org/internet/useful-ffmpeg-commands/28490/

  



  I can't ask the owner of the video to make it available as an .mp4 from within the adobe connect admin interface. Briefly, I would like to listen to those videos in x2 speed in VLC (just like what I do when listening to random math classes on YouTube - I put ON the x2 speed). The amount of time I would gain to watch adobe connect videos in x2 speed is MASSIVE.

  



  I think I am not the only one that would like to do this. There are a lot of questions on forums about downloading adobe connect videos, but the .flv format mixed with some .xml is generally a killer when the host does not make the videos properly available in .mp4.

  



  Dealing with the order of the .flv files is a puzzle. At least, I would not care to flush the chat away and leave some details like that behind, that would help to reconstruct the videos. Any scripts to automate the process would be useful.

  


• Low latency video shared in local gigabit network using linux [on hold]

  6 mai 2017, par user3387542

  For a robotics task we need to share the video (Webcam) live to about 6 or 7 users in the same room. OpenCV will be used on the clients to read the situation and send new tasks to the robots. Latency should not be much more than one second, the lower the better. What commands would you recommend for this ?

  We have one camera on a Linux host which wants to share the video to about 6 other units just some meters away.

  I already experimented with different setups. While raw-video looks like perfectly latency free (local loopback, the issue is the amount of data), any compression suddenly ads about a second delay.
  And how should we share this in the network. Is broadcasting the right approach ? How can it be so hard, they are right next to each other.

  Works locally, issues over the network.

  #server
  
  ffmpeg -f video4linux2 -r 10 -s 1280x720 -i /dev/video0 -c:v libx264 -preset veryfast -tune zerolatency -pix_fmt yuv420p -f mpegts - | socat - udp-sendto:192.168.0.255:12345,broadcast
  
  #client
  
  socat -u udp-recv:12345,reuseaddr - | vlc --live-caching=0 --network-caching=0 --file-caching=0 -

  raw video - perfectly fine like this, video with many artefacts if sent over the network

  ffmpeg -f video4linux2 -r 10 -s 1280x720 -i /dev/video0 -c:v rawvideo -f rawvideo -pix_fmt yuv420p - | vlc --demux rawvideo --rawvid-fps 10 --rawvid-width 1280 --rawvid-height 720 --rawvid-chroma I420 -

  The technology used doesen’t matter, we do not care about network load either. Just want to use opencv on different clients using live data.

• Saving highest quality video from video-capture card

  23 décembre 2013, par DusteD

  I have a machine with 2x3 3ghz dual-core xeon and 4x10krpm scsi 320 disks in raid0.
  The capture card is an osprey 560 64 bit pci card.
  Operating system is currently Windows Server 2003.

  The video-stream that I can open with VLC using direct show is rather nice quality.
  However, trying to save this video-stream without loss of quality has proven quite difficult,
  using the h264 codec I am able to achieve a satisfying quality, however, all 4 cores jump to 100% load after a few second and then it start dropping frames, the machine is not powerful enough for realtime encoding. I've not been able to achieve satisfying mpeg1 or 4 quality, no matter which bitrate I set..

  Thing is, the disks in this machine are pretty fast even by todays standard, and they are bored.. I don't care about disk-usage, I want quality.
  I have searched in vain for a way to pump that beautiful videostream that I see in VLC onto the disk for later encoding, I reckon the disks would be fast enough, or maybe something which would apply a light compression, enough that the disks can keep up, but not so much as to loose visible quality.

  I have tried FFMPEG as it seems capable of streaming a yuv4 stream down to the disk, but ofcause FFMPEG is unable to open the dshow device ( same error as this guy Ffmpeg streaming from capturing device Osprey 450e fails )

  Please recommend a capable and (preferably) software which can do this.