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• How to save frame from VOB with correct size ?

  18 mars 2017, par Paulo Barretto

  I am saving single frames from a vob file with ffmpeg.

  ffprobe shows for my vob file :

  Stream #0:1[0x1e0] : Video : mpeg2video (Main), yuv420p(tv), 720x480
  [SAR 8:9 DAR 4:3], Closed Captions, 3750 kb/s, 29.97 fps, 29.97 tbr,
  90k tbn, 59.94 tbc

  My command line is

  ffmpeg -i File1.vob -ss 10 -q:v 2 -vframes 1 -an -sn frame10s.jpg

  My jpeg files are being saved with 720x480, horizontally stretched. How can I make them be saved with correct display ratio 640x480 ?

• ffmpeg : init filtergraphs only after we have a frame on each input

  27 mai 2016, par Anton Khirnov

  ffmpeg : init filtergraphs only after we have a frame on each input
  This makes sure the actual stream parameters are used, which is
  
  important mainly for hardware decoding+filtering cases, which would
  
  previously require various weird workarounds to handle the fact that a
  
  fake software graph has to be constructed, but never used.
  
  This should also improve behaviour in rare cases where
  
  avformat_find_stream_info() does not provide accurate information.
  This merges Libav commit a3a0230. It was previously skipped.
  The code in flush_encoders() which sets up a "fake" format wasn’t in
  
  Libav. I’m not sure if it’s a good idea, but it tends to give
  
  behavior closer to the old one in certain corner cases.
  The vp8-size-change gives different result, because now the size of
  
  the first frame is used. libavformat reported the size of the largest
  
  frame for some reason.
  The exr tests now use the sample aspect ratio of the first frame. For
  
  some reason libavformat determines 0/1 as aspect ratio, while the
  
  decoder returns the correct one.
  The ffm and mxf tests change the field_order values. I’m assuming
  
  another libavformat/decoding mismatch.
  Signed-off-by : wm4 <nfxjfg@googlemail.com>
  

  • [DH] ffmpeg.c
  • [DH] ffmpeg.h
  • [DH] ffmpeg_cuvid.c
  • [DH] ffmpeg_filter.c
  • [DH] ffmpeg_opt.c
  • [DH] ffmpeg_qsv.c
  • [DH] tests/ref/fate/exr-rgb-scanline-pxr24-half-uint32-13x9
  • [DH] tests/ref/fate/exr-rgba-scanline-float-half-b44-12x8-l1
  • [DH] tests/ref/fate/exr-rgba-scanline-float-half-b44-12x8-l2
  • [DH] tests/ref/fate/exr-rgba-scanline-float-half-b44-13x9-l1
  • [DH] tests/ref/fate/exr-rgba-scanline-float-half-b44-13x9-l2
  • [DH] tests/ref/fate/exr-rgba-scanline-float-half-b44a-12x8-l1
  • [DH] tests/ref/fate/exr-rgba-scanline-float-half-b44a-12x8-l2
  • [DH] tests/ref/fate/exr-rgba-scanline-float-half-b44a-13x9-l1
  • [DH] tests/ref/fate/exr-rgba-scanline-float-half-b44a-13x9-l2
  • [DH] tests/ref/fate/vp8-size-change
  • [DH] tests/ref/lavf/ffm
  • [DH] tests/ref/lavf/mxf

• ffmpeg : corrupted video when using a different source image

  1er février 2017, par Sulli

  I am using the exact same command on two different images, to create a zoom in effect :

  ffmpeg -r 25 -i image1.jpg -filter_complex "scale=-2:10*ih,zoompan=z='min(zoom+0.0015,1.5)':d=125:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)',scale=-2:720" -y -shortest -c:v libx264 test1.mp4

  With image1.jpg, the video output is fine, but with image2.jpg it seems to be corrupted : although I can read the output video in VLC, I don’t see its thumbnail under Windows, and Adobe Premiere can’t read this file in the timeline.

  The two images are jpg downloaded from the web, and they both have the same ratio.

  What I am missing ?