Recherche avancée

Sur d’autres sites (9373)

• ffmpeg, get thumbnails but only part of the picture size [closed]

  29 mars 2013, par thevoipman

  I want to take a screenshot/thumbnail from a clip size is 1024x780, but I don't want the entire height, I just want the screenshot to take 768 x 80% of the height.... this is because I don't want any subtitles to be included in the thumbnails etc....

  I'm currently using the following command to get screenshots :

  ffmpeg -i "\"$OUTPUT_DIRECTORY/abc$OUTPUTFILENAME\"" -f image2 -ss ""$CURRENTPOSITION"" -s 768x432 -vf fps=fps=1/10 -vframes 20 "\""$OUTPUT_DIRECTORY/$RANDOM6%03d.jpg\""

  The goal is to end up a thumbnail size 768x432, but the height 432 is only 80% of the height of the original video file.

  Any kind of help I can get on this is greatly appreciated !

• Converting series of images with ffmpeg results in black video [migrated]

  27 avril 2013, par Marco Gagliardi

  I've just downloaded ffmpeg since it seems to perfectly match my needs (make a video from a set of pictures). I'm currently playing around with some examples just to get started and there's something weird happening that I can't explain.
  I'm trying this command (provided in the official documentation) :

  ffmpeg -f image2 -pattern_type glob -i 'foo-*.jpeg' -r 12 -s WxH foo.avi

  on a data set of 10 jpg pictures (of course I changed the pattern with '*.jpg'). The video seems to be encoded correctly but it's simply too fast to be sure about that (anyway it stops on the last frame that corresponds to the last picture). In order to get a longer video i thought to low the frame rate from 12 to 1 (one sec each picture) or 0.5 (2 sec each one) and so on.. no way ! with low rate values even if the video is played the pictures are simply not displayed. The player (VLC in my case) just shows a blank/empty video for a few seconds.

  Am I making something wrong or have I misunderstood the -r parameter ? Is it something related to codecs involved ? Finally.. How can i get each picture displayed for 1 or 2 seconds ?

  Here's the output :

  MacBook-Pro$ ffmpeg -f image2 -pattern_type glob -i '*.jpg' -r 1 -s 200x300 foo.avi
  
  ffmpeg version N-52517-g1e4f75d Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Apr 27 2013 19:41:11 with llvm-gcc 4.2.1 (LLVM build 2336.11.00)
  
    configuration: --disable-yasm
  
    libavutil      52. 27.101 / 52. 27.101
  
    libavcodec     55.  6.100 / 55.  6.100
  
    libavformat    55.  3.100 / 55.  3.100
  
    libavdevice    55.  0.100 / 55.  0.100
  
    libavfilter     3. 61.100 /  3. 61.100
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
  Input #0, image2, from '*.jpg':
  
    Duration: 00:00:00.40, start: 0.000000, bitrate: N/A
  
      Stream #0:0: Video: mjpeg, yuvj422p, 2560x1920 [SAR 1:1 DAR 4:3], 25 fps, 25 tbr, 25 tbn, 25 tbc
  
  File 'foo.avi' already exists. Overwrite ? [y/N] y
  
  Output #0, avi, to 'foo.avi':
  
    Metadata:
  
      ISFT            : Lavf55.3.100
  
      Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 200x300 [SAR 2:1 DAR 4:3], q=2-31, 200 kb/s, 1 tbn, 1 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mjpeg -> mpeg4)
  
  Press [q] to stop, [?] for help
  
  frame=    2 fps=0.0 q=2.0 Lsize=      43kB time=00:00:02.00 bitrate= 177.1kbits/s dup=0 drop=8    
  
  video:38kB audio:0kB subtitle:0 global headers:0kB muxing overhead 15.099197%
  
  MacBook-Pro$ 

• Revision 00d54aa331 : First pass clean up. One of a series of changes to clean up two pass allocation

  9 mai 2014, par Paul Wilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_firstpass.c

  
  
  First pass clean up.

  One of a series of changes to clean up two pass
  allocation as precursor to support for multiple arf
  or boosted frames per GF/ARF group.

  This change pulls out the calculation of the total bits
  allocated to a GF/ARF group into a function, to aid
  readability and reduce the line count for define_gf_group().

  This change should have no material impact on output.

  Change-Id : I716fba08e26f9ddde3257e7d9b188453791883a3