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• FFMPEG - Adding a full-frame image to the beginning of a video

  28 mars 2014, par user3470655

  I have tried many different ways to try to create a 10 second video file out of an image file and have used all the same switches and codecs as I used to encode my video file. However, when I concat the two using anything but complex_filter (which forces the video through another round of transcoding), the resulting video file is corrupt. I believe this is due to the inherent differences of the 10 second clip that ffmpeg created from the image, but there must be some way to get it to encode the exact same way as my video file.

  Here is the command I am using to turn the image into a 10s video clip (I added a silent mp3 because I thought that an audio stream starting partway through the video was messing things up) :

  ffmpeg -loop 1 -i splash.jpg -i silence.mp3 -c:v libx264 -preset slow -g 60 -r 29.97 -crf 16 -c:a libfdk_aac -b:a 256k -cutoff 18000 -t 5 tmpoutput1.mp4

  Here is the command I am using to encode my video :

  ffmpeg -i input.f4v -c:v libx264 -preset slow -g 60 -r 29.97 -crf 16 -c:a libfdk_aac -b:a 256k -cutoff 18000 tmpoutput2.mp4

  Here is the command I use to convert both of them to .ts to get ready for concat :

  ffmpeg -i tmpoutput1.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts tmpoutput1.ts

  And finally the concat (which is where I get crazy video corruption, everything along the way looks fine) :

  ffmpeg -i "concat:tmpoutput1.ts|tmpoutput2.ts" -c copy output.mp4

  Again, the issue is that I'm already transcoding everything once and I should be able to get it to transcode in a similar enough structure so that it can be concatenated without another transcode tacked onto the end.

  Has anyone successfully added a full-frame splash graphic to the front of a video with ffmpeg before ? I am using a brand new cross-compile of ffmpeg as I thought that might be the issue, but alas, the issue persists after the update.

  Thanks !

• Video capture using c++ Builder 10.3 and FFMPEG

  2 mai 2019, par Barry Andrews

  I am looking for an example of how I can use FFMPEG in c++ builder to create an application to record from usb capture device and playback video.

  I have tried Mitov components and winsoft camera which use directshow but their capture performance is poor.

  I need to capture 1920x1080 at up to 60fps into a compressed format and play this back later at both normal speed and slow speed.

• Reconstuct a video in exact same fps and bitrate as it was split

  4 octobre 2018, par ishandutta2007

  This is how I had split into frames(jpg),

  ffmpeg -i myvid.mp4 frame%05d.jpg -hide_banner

  This is how I am trying to reconstruct(mp4),

  ffmpeg -r 1/5 -i frame%05d.jpg -c:v libx264 -vf fps=25 -pix_fmt yuv420p myvid_recons.mp4

  But I am finding the recombined video is slow by a factor of 150x.
  I tries to expremint with fps optiob but found no improvement.