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• Concatination of images and videos in FFMpeg [closed]

  29 octobre 2023, par Juliano David Hilario

  I've been trying to concat pieces of videos with mix of images in FFMpeg and I can not achieve desired results. I'm trying to create a mock interview project for a friend, she answers the questions from a script. The question should be flashed in the screen before the footage of her answering is shown. The videos are encoded in H.265, with frame rate of 30fps, (via mediainfo) and when I try to concat the videos and images using the concat demuxer, it shows this message in rapid succession and only output the first image in the given duration in the output file : (meaning it failed when concating the video, I assume this is due to the fact that demuxed images doesn't have audio streams.)

  


  [png @ 0x55b4a4cb3540] Invalid PNG signature 0x3DB0201D430.
Error while decoding stream #0:0: Invalid data found when processing input


  


  the command I've used :

  


  ffmpeg -hide_banner -y -f concat -safe 0 -i concat.con -r 30 -c:v libx265 -c:a aac -pix_fmt yuv420p out.mp4


  


  the slice of concat.con file :

  


  file slides/1.png
duration 6
file parts/1.mp4
file slides/2.png
duration 8
file parts/2.mp4
file slides/3.png
duration 9
file parts/3.mp4
. . .
duration 12
file parts/9.mp4
file slides/10.png
duration 9
file parts/10.mp4



  


  Since, I need to get this done if possible today, I tried this route of turning the images into videos by this command :

  


  #!/bin/sh

ffmpeg -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=44100 -loop 1 -i "${1}.png" -c:v libx265 -r 30 -c:a aac -t "$2" -pix_fmt yuv420p "${1}_slide.mp4"


  


  This does create the desired result of a static video without sound but still has an audio channel (which is a pre-requisite for the concat demuxer), but when I concat it with the same command above with videos, the videos' audio desyncs and advances, now the video delays with the audio, which is not obviously feasable for the project. I suspect it has to do with frames and PTS, as MPV (a media player) logs when the duration of the video enters the video that has been concatinated that the PTS is invalid, and says :

  


  Invalid audio PTS: 6.037188 -> 6.553832

Audio/Video desynchronisation detected! Possible reasons include too slow
hardware, temporary CPU spikes, broken drivers, and broken files. Audio
position will not match to the video (see A-V status field).


  


  Tried turning the pictures into an image, and was expecting it to atleast sync with the audio

  


• Optical Drive Value Proposition

  28 août 2010, par Multimedia Mike — General

  I have the absolute worst luck in the optical drive department. Ever since I started building my own computers in 1995 — close to the beginning of the CD-ROM epoch — I have burned through a staggering number of optical drives. Seriously, especially in the time period between about 1995-1998, I was going through a new drive every 4-6 months or so. This was also during that CD-ROM speed race where the the drive packages kept advertising loftier ‘X’ speed ratings. I didn’t play a lot of CD-ROM games during that timeframe, though I did listen to quite a few audio CDs through the computer.

  
  
  

  I use “optical drive” as a general term to describe CD-ROM drives, CD-R/RW drives, DVD-ROM drives, DVD-R/RW drives, and drives capable of doing any combination of reading and writing CDs and DVDs. In my observation, optical media seems to be falling out of favor somewhat, giving way to online digital distribution for things like games and software, as well as flash drives and external hard drives vs. recordable or rewritable media for backup and sneakernet duty. Somewhere along the line, I started to buy computers that didn’t even have optical drives. That’s why I have purchased at least 2 external USB drives (seen in the picture above). I don’t have much confidence that either works correctly. My main desktop until recently, a Mac Mini, has an internal optical drive that grew flaky and unreliable a few months after the unit was purchased.

  I just have really rotten luck with optical drives. The most reliable drive in my house is the one on the headless machine that, until recently, was the main workhorse on the FATE farm. The eject switch didn’t work correctly so I have to log in remotely, 'sudo eject', walk to the other room, pop in the disc, walk back to the other room, and work with the disc.

  Maybe optical media is on its way out, but I still have many hundreds of CD-ROMs. Perhaps I should move forward on this brainstorm to archive all of my optical discs on hard drives (and then think of some data mining experiments, just for the academic appeal), before it’s too late ; optical discs don’t last forever.

  So if I needed a good optical drive, what should I consider ? I’ve always been the type to go cheap, I admit. Many of my optical drives were on the lower end of the cost spectrum, which might have played some role in their rapid replacement. However, I’m not sold on the idea that I’m getting quality just because I’m paying a higher price. That LG unit at the top of the pile up there was relatively pricey and still didn’t fare well in the long (or even medium) term.

  Come to think of it, I used to have a ridiculous stockpile of castoff (but somehow still functional) optical drives. So many, in fact, that in 2004 I had a full size PC tower that I filled with 4 working drives, just because I could. Okay, I admit that there was a period where I had some reliable drives.

  That might be an idea, actually– throw together such a computer for heavy duty archival purposes. I visited Weird Stuff Warehouse today (needed some PC100 RAM for an old machine and they came through) and I think I could put together such a box rather cheaply.

  It’s a dirty job, but… well, you know the rest.

• Rotated video with ffmpeg doesn't play in flowplayer in IE9

  17 octobre 2013, par yoshi

  I have a script that rotates videos 90 degrees and then the videos are displayed on a web page using flowplayer (HTML5 version, not Flash). After the video is rotated once it does not play in IE9 but plays without any other problems in Chrome and Firefox.
  The error message is : Video file not found.

  I've looked in IE9's developer tools console, in the network tab and the browser streams the whole video.

  The following is the ffmpeg command I use to rotate and convert the video :

  ffmpeg -i input.mov -y -r 30 -b 4M -vf 'transpose=1,scale=800:trunc(ow/a/2)*2' -ar 48000 -vcodec libx264 -profile baseline -preset slow -level 2.2 output.mp4

  This is the input file which I used : https://dl.dropboxusercontent.com/u/37994/local%20capture.mov

  This is the output video : https://dl.dropboxusercontent.com/u/37994/local%20capture%20rotated.mp4

  The input video from above is a screen capture made using QuickTime on Mac OS.

  This also happened for this video : http://mirrorblender.top-ix.org/peach/bigbuckbunny_movies/big_buck_bunny_480p_h264.mov
  And also this one : https://dl.dropboxusercontent.com/u/37994/clipcanvas_14348_offline.mp4

  This didn't happen for the sample .mov from here : http://support.apple.com/kb/ht1425

  If I run the command twice, meaning I rotate the video 90 degrees and then I rotate the output using the same command once more, the problem disappears, but I need to be able to rotate only 90 degrees.

  This problem doesn't happen if I put IE9 in IE7 or IE8 compatibility mode.

  I was thinking that maybe the problem was how the server serves the video but there's no problem with other videos.

  I looked at the metadata with ffmpeg but didn't see anything significant.

  I already have AddType video/mp4 .mp4 in .htaccess.

  I can't seem to pin down what's causing this problem.

  Edit :

  Request in IE9
  

  Response in IE9