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• ffmpeg weird x264 encoding behavior

  1er février 2016, par JMor

  I have a captured a 720x480 video with a display aspect ratio of 16:9 which I want to crop, resize and pad, but just the x264 encoding command is giving me a headache.

  (Screenshot of input.m2v) Here is my command :

  ffmpeg -ss 1861 -i input.m2v -c:v libx264 -profile:v main -preset:v medium -level 3.1 -x264opts crf=21.228 -t 60 -y -f mp4 output.mp4

  And here is the ffmpeg output :

  (Screen shot of output.mp4)

  Input #0, mpegvideo, from 'input.m2v':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: mpeg2video (Main), yuv420p(tv), 720x480 [SAR 32:27 DAR 1
  
  6:9], max. 6605 kb/s, 31.02 fps, 59.94 tbr, 1200k tbn, 59.94 tbc
  
  [libx264 @ 02ba84c0] using SAR=32/27
  
  [libx264 @ 02ba84c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  
  [libx264 @ 02ba84c0] profile Main, level 3.1
  
  [libx264 @ 02ba84c0] 264 - core 144 r2525 40bb568 - H.264/MPEG-4 AVC codec - Cop
  
  yleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deb
  
  lock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 m
  
  e_range=16 chroma_me=1 trellis=1 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chro
  
  ma_qp_offset=-2 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1
  
  interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
  
   b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scene
  
  cut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=21.2 qcomp=0.60 qpmin
  
  =0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'output.mp4':
  
    Metadata:
  
      encoder         : Lavf56.19.100
  
      Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 720x48
  
  0 [SAR 32:27 DAR 16:9], q=-1--1, 29.97 fps, 30k tbn, 29.97 tbc
  
      Metadata:
  
        encoder         : Lavc56.21.102 libx264
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mpeg2video (native) -> h264 (libx264))

  The output size is 720x480, displayed as 853x480, as expected.
  But it looks like the frame has been vertically scaled by a factor of 1.18 and then cropped to a height of 480, so that I am losing the top and bottom of the frame. In fact, the behavior is equivalent to :

  -vf "scale=720:569,crop=720:480:0:0"

  Although I assume the aspect ratio plays a part here (I think the 1.18 factor is really (16/9)/(720/480)) I am surprised that ffmpeg would do that out of the blue. May be someone more knowledgeable than me could explain it ?

• Python - playing video using ffplay displays file in larger resolution

  10 décembre 2019, par derBrain

  I’m working on a simple script that plays a video using ffplay.
  The problem I’m running into is that the output file has a larger resolution than it should have.
  The resolution of the file to be played is 1280x720, however, when I open the file with ffplay, the output is scaled to 1920x1080.
  I even tried to downscale the output by factor 1.5 (to get it to play in 1280x720), but the quality is noticeably worse compared to playing the same file in VLC player.
  What am I missing here ?

  This is the code I’m using :

  dbFile = "file.mp4"
  
  open_dbFile = "ffplay {0} -window_title {1} -left 50 -top 50 -nostats".format(dbFile, "DB_file")
  
  sub.Popen(open_dbFile)

  this is the log :

  ffplay version N-95171-g6ca3d34ff8 Copyright (c) 2003-2019 the FFmpeg developers
  
    built with gcc 9.2.1 (GCC) 20190918
  
  
  
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
  
    libavutil      56. 35.100 / 56. 35.100
  
    libavcodec     58. 59.101 / 58. 59.101
  
    libavformat    58. 33.100 / 58. 33.100
  
    libavdevice    58.  9.100 / 58.  9.100
  
    libavfilter     7. 59.100 /  7. 59.100
  
    libswscale      5.  6.100 /  5.  6.100
  
    libswresample   3.  6.100 /  3.  6.100
  
    libpostproc    55.  6.100 / 55.  6.100
  
  
  
  Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      creation_time   : 2017-12-24T15:03:27.000000Z
  
    Duration: 00:08:36.83, start: 0.000000, bitrate: 588 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1280x720 [SAR 1:1 DAR 16:9], 459 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc (default)
  
      Metadata:
  
        creation_time   : 2017-12-24T15:03:27.000000Z
  
        handler_name    : ISO Media file produced by Google Inc. Created on: 12/24/2017.
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
  
      Metadata:
  
        creation_time   : 2017-12-24T15:03:27.000000Z
  
        handler_name    : ISO Media file produced by Google Inc. Created on: 12/24/2017.
  
     1.59 A-V: -0.014 fd=   0 aq=   19KB vq=   30KB sq=    0B f=0/0

  Thanks for your help !
  db

• Problems accessing codecs with ggplot and gganimate

  19 décembre 2016, par noLongerRandom

  Using gganimate. Can’t figure out how to properly access functionality of ffmpeg, specifically I want to change the codec I’m using in the video file I’m outputting.

  # load packages
  
  library(ggplot)
  
  library(animation)
  
  library(gganimate)
  
  
  
  # Here's my data.frame
  
  myDf <- data.frame(
  
      year = c(1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014), 
  
      bottom50 = c(0.195, 0.191, 0.187, 0.192, 0.196, 0.205, 0.207, 0.210, 0.209, 0.204, 0.203, 0.204, 0.205, 0.203, 0.202, 0.200, 0.200, 0.201, 0.199, 0.195, 0.190, 0.183, 0.179, 0.179, 0.177, 0.172, 0.169, 0.169, 0.168, 0.166, 0.158, 0.159, 0.158, 0.154, 0.151, 0.148, 0.149, 0.148, 0.146, 0.149, 0.148, 0.145, 0.142, 0.138, 0.135, 0.137, 0.137, 0.136, 0.130, 0.127, 0.123, 0.127, 0.125), top1 = c(0.126, 0.127, 0.129, 0.128, 0.126, 0.123, 0.122, 0.115, 0.110, 0.111, 0.111, 0.109, 0.106, 0.105, 0.105, 0.107, 0.108, 0.111, 0.107, 0.110, 0.112, 0.115, 0.125, 0.125, 0.122, 0.133, 0.149, 0.145, 0.145, 0.139, 0.150, 0.146, 0.147, 0.153, 0.160, 0.166, 0.169, 0.177, 0.183, 0.173, 0.171, 0.172, 0.183, 0.194, 0.201, 0.199, 0.195, 0.185, 0.198, 0.196, 0.208, 0.196, 0.202)
  
  )
  
  
  
  #Basic plot
  
  p <- ggplot(myDf, aes(x = year, y = bottom50, frame = year)) + 
  
      geom_line(color = "dodgerblue") + 
  
      geom_line(aes(y = top1), color = "darkred")

  The non-animated version gets me what I want :

  

  And I get an animation version output to video with :

  gganimate(p, interval = .1, title_frame = FALSE, "income.mp4")

  That’s fine, but I want to change some the output parameters, specifically : alter the dimensions, the frame rate, and use a different codec.

  # change some of the options
  
  ani.options(ani.height = 1080, ani.width = 1920, 
  
              interval = 0.04166667, other.opts = "-vcodec qtrle -f mov")
  
  # re-animate
  
  gganimate(p, title_frame = FALSE, "income.mov")

  That gives me the following error :

  Error in animation_saver(saver, filename) : 
  
    Don't know how to save animation of type mov

  I’m using ’.mov’ as my file extension because I’m trying to change to the Animation codec (so it’s no longer a .mp4 wrapper). I’ve got ffmpeg installed, so this is probably a syntax issue. But the documentation isn’t very clear here ; gganimate doesn’t have any documentation on changing codecs (or outputting any video besides an mp4), and the animation package is light on specifics as well.