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• How to handle queueing of video encoding during multiple video uploads ?

  6 mars 2016, par Yash Desai

  I am working on developing a video streaming site where users can upload videos to the site (multiple videos at once using the uploadify jquery plugin).

  Now, I am faced with the question of encoding the videos to FLV for streaming them online.

  When should the video encoding process take place ? Should it take place immediately after uploads have finished (i.e redirect the user to upload success page, and then start encoding in the background using exec command for ffmpeg ?) However, using this approach, how do i determine if the encoding has finished successfully ? What if users upload a corrupt video and ffmpeg fails to encode it ? How do i handle this in PHP ?

  How do i queue encoding of videos since multiple users can upload videos at the same ? Does FFMpeg has its own encoding queue ?

  I also read about gearman and message queueing options such as redis and AMQP in another related SO thread. Are these one of the potential solutions ?

  I would really appreciate if someone could give answers to my questions.

• Where can I get 16-bit video sequences ? [on hold]

  9 mai 2017, par govind

  I understand that I can create 16-bit videos from 8-bit ones, but I want to work on actual 16-bit data (for a class project) and not just the bit-shifted pixel values. I just want to extract and work on the 16-bit Luma component from the video.

  https://media.xiph.org/ has 16-bit raw contents but the file size is 500GB. I would like to limit my downloads to 1-2 GB.
  The footnote at https://media.xiph.org/video/derf/ says "These were converted from 16-bit linear RGB to Y’CbCr", can I get the source from which these conversion took place.

  I could create my own content with some custom pattern but that’s not an option since I want to work on natural-looking imagery.

  I do understand that regular monitors can only display 8-bit. I also understand that it’s not a typical StackOverflow question, but I have already spent 2 hours online searching for it. Any links will be appreciated. Thanks in advance.

• ffmpeg convert video to size 275x157 pixels [closed]

  21 janvier 2024, par degr

  I want to make video of exact size 275x157, but ffmpeg always make it 274x156.

  


  So far I try next list of commands :

  


  //it from my opinion, it should make vide of my size, and add padding if necessary, but result is same - 274x156
ffmpeg -i ScreenRecorderProject7.mkv  -strict -2 -filter:v "pad=275:157:(275-iw*min(275/iw\,157/ih))/2:(157-ih*min(275/iw\,157/ih))/2" WrathTrailer1334x750.mp4

//more advanced variant of previous command, not work also
ffmpeg -i ScreenRecorderProject7.mkv  -strict -2 -filter:v "pad=275:157:(275-iw*min(275/iw\,157/ih))/2:(157-ih*min(275/iw\,157/ih))/2" WrathTrailer1334x750.mp4

//it told width is not divisible by 2
ffmpeg -i ScreenRecorderProject5.mkv -strict -2 -vf scale=275x157 -aspect 1.75259 output.mp4

//in description it was mentioned it add 1px pad, but I feel it is wrong; result incorrect
ffmpeg -i ScreenRecorderProject5.mkv -strict -2 -vf pad="width=ceil(iw/2)*2:height=ceil(ih/2)*2" output.mp4


  


  Also I try to do so with movavi video editor, streamlabs and couple online video converters and always I'm getting wrong resolution. Cant understand what is wrong with that numbers