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• ffmpeg scale/forcing a video resolution issue

  30 janvier 2018, par Massimo Vantaggio

  I try to be sure that the video comes out with a resolution of 1920 x1080,
  If not the encoding must force this resolution.
  I need this to create fine adaption set from a video input with standard resolution (HD).

  Im unable to get always this resolution, for example with a movie of
  1920 x 1040 i get 1993 x 1080

  , below my ffmpeg command line :

  ffmpeg -y -i $name -i logo1080.png -c:a aac -b:a 256k -ar 48000 -ac 2 -async 1 -c:v libx264 -x264opts keyint=$GOP:min-keyint=$GOP:no-scenecut -bf 0 -r $FPSC -b:v 2400k -maxrate 2400k -bufsize 1200k -profile:v main -t $FDUR -filter_complex "[0:v][1:v]overlay=main_w-overlay_w-10:10,scale=1920:1080" format1080.mp4

  I tried every possibility that the ffmpeg scale page tells, without understand how to fix it.
  I think i need some help,
  Thanks,
  Massimo

• MP4Box Resolution unmatched between representation

  30 janvier 2018, par Massimo Vantaggio

  for one of the last stability tests i try with two representation instead the only one of before to get the adaptive bitrate streaming .
  Below my encoding command :

  ffmpeg -y -i $name -i logo.png -c:a aac -b:a 256k -ar 48000 -ac 2 -async 1 -c:v libx264 -x264opts keyint=$GOP:min-keyint=$GOP:no-scenecut -bf 0 -r $FPSC -b:v 1060k -maxrate 1060k -bufsize 530k -profile:v main -t $FDUR -filter_complex "[0:v][1:v]overlay=main_w-overlay_w-10:10,scale=-1:478" format480.mp4
  
  
  
  ffmpeg -y -i $name -i logo.png -c:a aac -b:a 384k -ar 48000 -ac 2 -async 1 -c:v libx264 -x264opts keyint=$GOP:min-keyint=$GOP:no-scenecut -bf 0 -r $FPSC -b:v 2400k -maxrate 2400k -bufsize 1200k -profile:v main -t $FDUR -filter_complex "[0:v][1:v]overlay=main_w-overlay_w-10:10,scale=-1:1080" format1080.mp4

  If for the first rapresentation i use 480p ffmpeg give me this error :

  width not divisible by 2 (853x480)
  Error initializing output stream

  If i use for first representation 478p ffmpeg run correctly all two encoding but after when i try to load these two files on MP4Box to dash them live with the following command :

  MP4Box -dash-live 8000 -subdur 8000 -profile dashavc264:live -mpd-refresh 240.0 -time-shift 24 -min-buffer 4000 -insert-utc -no-cache -out manifest.mpd format1080.mp4#video format480.mp4#video format1080.mp4#audio format480.mp4#audio

  the error come back into mp4box :
  "files have not-proportional layout 1920 x 1080 vs 849 x 478 but sample size and aspect ratio match, assuming precision issue"

  I would like to understand what i don’t know about, which are the resolutions that match, i understand that some movies have atypical resolution for example 1040 or 432 but the input video for this test is correct 1920 X 1080 and i wish to compress/encode it for dash and to create another representation with 480p, could i ask where I’m wrong ?
  Thanks !
  Massimo

• Error trying to decode 4K video using NVDEC

  19 avril 2024, par Nestoraj

  I am trying to convert a 4K HEVC MKV file of 70GB into another HECV file but with less size. I am using FFmpeg with Nvidia acceleration but when I execute the following command an error appears :

  



  ffmpeg -y -vsync 0 -hwaccel_device 0 -hwaccel cuvid -c:v hevc_cuvid -i input.mkv -c:a copy -c:v hevc_nvenc -preset slow -b:v 10M -bufsize 10M -maxrate 15M -qmin 0 -g 250 -bf 2 -temporal-aq 1 -rc-lookahead 20 -i_qfactor 0.75 -b_qfactor 1.1 output.mkv


  



  The error is :

  



  [hevc_nvenc @ 0000021036b0d000] Provided device doesn't support required NVENC features
Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height


  



  The video file has these details :

  



  

  



  It seems that FFmpeg cannot recognize my GPU as a supported device to decode but I have read that Nvidia has support for my card with NVDEC.

  



  I am running Windows 10 64 bits with i7 4790 and GTX 1080