Recherche avancée

Sur d’autres sites (6367)

• libavcodec/amfenc_hevc : Recommend values for min and max video quantizer scale.

  9 mars 2021, par Ovchinnikov Dmitrii

  libavcodec/amfenc_hevc : Recommend values for min and max video quantizer scale.
  Current settings makes bitrate larger than expected, more information :
  
  https://github.com/HandBrake/HandBrake/issues/3447#issue-820490736
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] libavcodec/amfenc_hevc.c

• FFMpeg : scale down videos with maximum width and height while maintaining aspect ratio

  20 février 2021, par R3D34THR4Y

  In my program the user can input any video file he wants and have it transcoded ready for social media no matter its dimensions and aspect ratio.
The "export profiles" have many variables but the important ones here are maxheight and maxwidth.

  


  The FFMpeg filters must output a video that follows the following rules :

  


  

  • If the video is vertical, permutate the maxheight and maxwidth values (social media considers both 1280x720 and 720x1280 as "720P")

  


  • The video must not have a height superior to maxheight or a width superior to maxwidth.

  


  • The original video and exported video have the same aspect ratio and no distortion occurs.

  


  • No padding or cropping should occur.

  


  • The video should not be scaled if it is already under those maximum dimensions (no upscaling).

  


  • The function must work even with odd input resolutions.

  


  


  I have tried finding a combination of filters that do that but I haven't been able so far, either the video gets distorted or it gets huge black bars if the aspect ratio isn't right, the solution may be simple but I'm a beginner on this library so I'm probably just missing an easy solution.

  


  My current solution :

  


  ffmpeg -i input.mp4 -vf [in] scale=1280:720:flags=lanczos:force_original_aspect_ratio=decrease,pad=1280:720:(ow-iw)/2:(oh-ih)/2,setsar=1 [res]; [res] format=yuv420p [format] -c:v libx264 -c:a aac -movflags +faststart output.mp4


  


  Thanks for reading

  


• ffmpeg error : Unable to find a suitable output format for 'scale=1500:1000'

  13 février 2021, par Tomáš Zato - Reinstate Monica

  I am trying to convert a bunch of images into a video. The original image resolution is 6000x4000, but if I use ffmpeg to create a video with that resolution, no player can even play it because it's way to huge.

  


  I tried to set the output resolution as such, dividing the input resolution by 4 :

  


  ffmpeg -r 60 -s 1500x1000 -start_number 3790 -i DSC_%04d.jpg -vcodec libx264 -crf 25  -pix_fmt yuv420p ../video_lowres.mp4


  


  This had no effect and still produced 6000x4000 video. So instead, I tried this parameter : scale=1500:1000 The full command I ran :

  


  ffmpeg -r 60 scale=1500:1000 -start_number 3790 -i DSC_%04d.jpg -vcodec libx264 -crf 25  -pix_fmt yuv420p ../video_lowres.mp4


  


  But I got this error :

  


  [NULL @ 000002ad897bd9c0] Unable to find a suitable output format for 'scale=1500:1000'
scale=1500:1000: Invalid argument


  


  How can I create a downscaled video from photos using ffmpeg ?