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• rtmpproto : Validate the embedded flv packet size before copying

  3 octobre 2013, par Martin Storsjö

  rtmpproto : Validate the embedded flv packet size before copying
  This wasn’t an issue prior to 58404738, when the whole RTMP packet
  
  was copied at once and the length of the individual embedded flv
  
  packets only were validated by the flv demuxer.
  Prior to this patch, this could lead to reads and writes out of bound.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavformat/rtmpproto.c

• How to detect a common scene in a set of videos with ffmpeg

  6 août 2019, par Hans J

  I have a set of videos that are assumed to contain a common (or very similar) scene. I want to be able to detect (with FFmpeg) what that common scene is, how long the scene is, and where the scene is in each individual video.

  The scene would be assumed to be longer than 10 seconds (This is an arbitrary choice, it can be changed).

  The final output of the command would include the various time-codes of the instance of the scene in each video. Assuming a timebase 1/1, with a common scene that is 60 seconds long, an output would along the lines of :

  Video1.mp4 0 60
  
  Video2.mp4 120 180
  
  Video3.mp4 50 110
  
  Video4.mp4 null

  where video4 does not contain any common scene.

  For example, I could have three episodes of a TV show. They all contain the same commercial. Without knowing what that commercial is, I want to be able to find where that commercial shows up in each of the episodes.

  Note : For the purpose of a good solution, the common scenes do not have to exactly match. Because there could be artifacts or embedded subtitles in one episode and not the other.

• How to get FFMPEG to use more GPU when encoding

  24 mars 2023, par Entropy

  so the situation is as following

  


  Im receiging 20/30 uncompressed image per second. format is either PNG or Bitmap. Each individual photo size is between 40 and 50 mb (all have same size since uncompressed).

  


  I want to encode them to a 265 lossless video and stream them to a http server using FFMPEG.
The output video is 1920x1080, so there is some downsampling.
Compression is allowed but nothing is allowed to be lost other than the down sampling.

  


  now i m still in the testing phase. i have a 500 sample image. and i m tryng to encode them as effeciently as possible.
Im using commands such as :

  


  ffmpeg  -hwaccel cuvid -f  image2  -i "0(%01d).png" -framerate 30 / 
-pix_fmt p010le -c:v hevc_nvenc -preset lossless -rc vbr_hq /
-b:v 6M -maxrate:v 10M  -vf scale=1920:1080  -c:a aac -b:a 240k result.mp4


  


  I have a powerfull modern quadro GPU and a 6 cores intel CPU and an Nvme hard drive.

  


  The usuage of the GPU when encoding is exactly 10%, CPU is circa 30-40%

  


  How can i get GPU usuage to 80% ? The machine on which im going to run the code will have at leat a quadro 4000 (maybe stronger) and i want to use it to the fullest