Sur d’autres sites (2389)

• What is the most suitable H265 setting converting from H264 on ffmpeg ?

  9 juin 2017, par minion007

  Currently, I was trying to convert my videos no matter personal videos or movies from H264 to H265. But that was much harder than what I expected.

  Firstly, it took me over 10 hours to build ffmpeg on Linux and I believe I’m still having some problems on dealing with this.

  Secondly, I notice there is degradation after converting by using the setting or parameters from Internet or ffmpeg official website. On the other hand, the video size would be the same or even bigger than the original video size if I use small crf like 23 or 28.

  For instance, sudo ffmpeg -i input.mp4 -c:v hevc -x265-params lossless -preset medium -crf 30 -c:a copy output.mkv

  sudo ffmpeg -i input.mp4 -c:v libx265 -x265-params lossless -preset medium -crf 30 -c:a copy output.mkv

  the above two settings give me the very small video size (between 21% 23% of the original video) which is the main reason why I want to convert my videos to H265 but drawback would be the quality of converted video is worse than the original video (I would may be between 30% 35% degradation).

  Thirdly, the size of video would be much bigger than the original size of video if I use the lossless parameter.

  sudo ffmpeg -i input.mp4 -c:v libx265 -x265-params lossless=1 -preset medium -crf 30 -c:a copy output.mkv

  the above setting can keep the quality of the original video but size would be huge (above 200% of original video).

  Is there any suggestion ?

• Interplay MVE : Implement frame format 0x10

  25 juin 2017, par Hein-Pieter van Braam

  Interplay MVE : Implement frame format 0x10
  This implements the 0x10 frame format for Interplay MVE movies. The
  
  format is a variation on the 0x06 format with some changes. In addition
  
  to the decoding map there's also a skip map. This skip map is used to
  
  determine what 8x8 blocks can change in a particular frame.
  This format expects to be able to copy an 8x8 block from before the last
  
  time it was changed. This can be an arbitrary time in the past. In order
  
  to implement this this decoder allocates two additional AVFrames where
  
  actual decoding happens. At the end of a frame decoding changed blocks
  
  are copied to a finished frame based on the skip map.
  The skip map's encoding is a little convulted, I'll refer to the code
  
  for details.
  Values in the decoding map are the same as in format 0x06.
  Signed-off-by : Hein-Pieter van Braam <hp@tmm.cx>
  

  • [DH] libavcodec/interplayvideo.c
  • [DH] libavformat/ipmovie.c

• Interplay MVE : Implement frame format 0x06

  25 juin 2017, par Hein-Pieter van Braam

  Interplay MVE : Implement frame format 0x06
  This implements the 0x06 frame format for Interplay MVE movies. The
  
  format is relatively simple. The video data consists of two parts :
  16 bits per 8x8 block movement data
  
  a number of 8x8 blocks of pixel data
  For each 8x8 block of pixel data the movement data is consulted. There
  
  are 3 possible meanings of the movement data :
  
  * zero : copy the 8x8 block from the pixel data
  
  * negative : copy the 8x8 block from the previous frame from an offset
  
               determined by the actual value of the entry -0xC000.
  
  * positive : copy the 8x8 block from the current frame from an offset
  
               determined by the actual value of the entry -0x4000
  Decoding happens in two passes, in the fist pass only new pixeldata is
  
  copied, during the second pass data is copied from the previous and
  
  current frames.
  The codec expects that the current frame being decoded to still has the
  
  data from 2 frames ago on it when decoding starts.
  Signed-off-by : Hein-Pieter van Braam <hp@tmm.cx>
  

  • [DH] libavcodec/interplayvideo.c
  • [DH] libavformat/ipmovie.c