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• FFMPEG lossless simple & efficient format

  30 octobre 2016, par Adminy

  I took a sample video and ran this code for each image format like this :

  ffmpeg -i test.mkv png/%d.png
  
  ffmpeg -i test.mkv bmp/%d.bmp

  What I noted is that BMP at 1080P has a fixed size of 5.97 MB (6,266,934 bytes)

                                                             !6,220,800

  Then I did some maths :

  1 byte = 2^8 == 256 possible combinations
  
  r + g + b form a color (0-255,0-255,0-255)
  
  bmp = 3 * 1920 * 1080 = 6,220,800 bytes

  So extra is just the file headers ?! (46134 bytes for just headers ?)

  Next thing I noted that PNG size is dynamic and when the image has a lot of repetition is somewhere 2.5mb. Usually its between 10mb and 12mb.

  Also decoding BMP seemed a lot quicker compared to PNG. So there is no point in even looking at PNG. I would like to know why is it so huge over BMP if it has (zlib) compression factor.

  What is the best format to export to in terms of speed and size, preferred if its as simple as reading the file of color bytes ?

• Ffmpeg won't copy excerpt of video correctly

  5 mai 2022, par JR Jr.

  I am using a DOS batch to automate and copy excerpts of various high definition videos (mkv's with more than 1GB each).
The script is very convenient and runs fast and fine, but Ffmpeg is not doing its job correctly (it seems Murphy's law is inexorably enthralled into technology, things never come easy, which is why I love and hate it).

  


  Anyway, to cut a long story short, each time the batch job runs, a code like below is executed (pardon me the indiscrete folder name, it's about the 90's TV show, it's not porn !).

  


  call "C:\ffmpeg\bin\ffmpeg.exe" -y -i "D:\100\Sexo\S01\SATC - S01E03 - Bay of Married Pigs.mkv" -ss 00:18:05 -to 00:19:15 -codec copy "002-SATC - S01E03 - Bay of Married Pigs-00_18_05-00_19_15.mp4"


  


  The problem is that the first 6 seconds or so of the resulting video has no video, only audio with a frozen image that only starts to move after about 6 seconds, which is a huge defect, not to mention very annoying (a big let down, after all my meticulous scripting work :(). And this happens for most of the files, except a few ones.

  


  Even though this is copying and changing the format from mkv to mp4, per another thread on this site (https://askubuntu.com/questions/396883/how-to-simply-convert-video-files-i-e-mkv-to-mp4), this is not re-encoding, so this is not the issue. Actually, the same problem occurs even if I don't change the format from mkv to mp4.

  


  Even though I foresee a "there's no way to fix this", let me ask : is there a way to fix this ? Hopefully there is a way.

  


• How do i convert (pulled from device) individual frames to a video file on linux and push it back to the same directory

  31 mars 2012, par RiASh

  First of all i have frames on my SD Card and frames are there in separate folders for each video..

  what i want to do is that i just want to make REALLY simple Java application for user(just a button to make video files) on the linux OS whose ActionEvent Handler pulls in all the individual frames and converts it to a video..deletes all the frames from the SD Card and then pushes the video file back to the same directory of SD Card..

  i wanted to know how do i pack frames into a video file on Linux(Ubuntu)..i think there is something ffmpeg but i dont know much..
  Can someone provide a example..please .. the images are named as image0000 to image9999

  and is it possible to create video file from those frames AND EVEN having sound in them using ffmpeg..?

  Can adb pull and push files without SD Card being connected..

  And finally wanted to know how do i run shell commands like adb pull, push, ffmpeg from JAVA..

  THERE ARE i think 4 QUESTIONS here but all related so i thought better ask them together..Thanks in advance ! :)