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• ffmpeg stuck in generating thumbnail of video [closed]

  10 décembre 2019, par user6121419

  I’m trying to create a thumbnail of a .mov video with ffmpeg, but it gets stuck.
  I tried the same command on 2 different machines and with different types of arguments, but nothing changed the result. The video itself can be viewed without a problem, so it shouldn’t be corrupted.
  The video was taken on an iphone at 4k 60fps.

  What I’ve tried :

  ffmpeg -i IMG_1001.MOV -ss 00:00:02 -vframes 1 thumbnail.jpg

  It gets stuck at the third last line frame= 0 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=   0x and from then on, I stopped the process with ctrl+c

  Output :

  ffmpeg version 3.4.6-0ubuntu0.18.04.1 Copyright (c) 2000-2019 the FFmpeg developers
 built with gcc 7 (Ubuntu 7.3.0-16ubuntu3)
 configuration: --prefix=/usr --extra-version=0ubuntu0.18.04.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
 libavutil      55. 78.100 / 55. 78.100
 libavcodec     57.107.100 / 57.107.100
 libavformat    57. 83.100 / 57. 83.100
 libavdevice    57. 10.100 / 57. 10.100
 libavfilter     6.107.100 /  6.107.100
 libavresample   3.  7.  0 /  3.  7.  0
 libswscale      4.  8.100 /  4.  8.100
 libswresample   2.  9.100 /  2.  9.100
 libpostproc    54.  7.100 / 54.  7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'IMG_1001.MOV':
 Metadata:
   major_brand     : qt
   minor_version   : 0
   compatible_brands: qt
   creation_time   : 2019-11-xx
   com.apple.quicktime.make: Apple
   com.apple.quicktime.model: iPhone 8
   com.apple.quicktime.software: 13.2.2
   com.apple.quicktime.creationdate: 2019-11-xx
 Duration: 00:00:05.18, start: 0.000000, bitrate: 54961 kb/s
   Stream #0:0(und): Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv, bt709), 3840x2160, 54851 kb/s, 60 fps, 60 tbr, 600 tbn, 600 tbc (default)
   Metadata:
     creation_time   : 2019-11-xx
     handler_name    : Core Media Data Handler
     encoder         : HEVC
   Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 94 kb/s (default)
   Metadata:
     creation_time   : 2019-11-xx
     handler_name    : Core Media Data Handler
   Stream #0:2(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
   Metadata:
     creation_time   : 2019-11-xx
     handler_name    : Core Media Data Handler
   Stream #0:3(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
   Metadata:
     creation_time   : 2019-11-xx
     handler_name    : Core Media Data Handler
Stream mapping:
 Stream #0:0 -> #0:0 (hevc (native) -> mjpeg (native))
Press [q] to stop, [?] for help
[swscaler @ 0x55d83a288940] deprecated pixel format used, make sure you did set range correctly
Output #0, image2, to 'thumbnail.jpg':
 Metadata:
   major_brand     : qt
   minor_version   : 0
   compatible_brands: qt
   com.apple.quicktime.creationdate: 2019-11-xx
   com.apple.quicktime.make: Apple
   com.apple.quicktime.model: iPhone 8
   com.apple.quicktime.software: 13.2.2
   encoder         : Lavf57.83.100
   Stream #0:0(und): Video: mjpeg, yuvj420p(pc), 3840x2160, q=2-31, 200 kb/s, 60 fps, 60 tbn, 60 tbc (default)
   Metadata:
     creation_time   : 2019-11-xx
     handler_name    : Core Media Data Handler
     encoder         : Lavc57.107.100 mjpeg
   Side data:
     cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
frame=    0 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=   0x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)

  Any idea on what it could be ? Am I missing something or could it be that the encoding can’t be read properly by ffmpeg ? Besides that I haven’t found any alternative to generate thumbnails from videos on linux

• Inconsistent Rotation of Output Video OpenCV

  27 avril 2021, par user530316

  I am reading in mobile videos shot on an iphone (.MOV format). When the video is shot upright, ffmpeg meta data states the video frames are rotated 90 clockwise. When I read the video in with opencv as a .MOV and then outwrite again with opencv as a .mp4, both the input and output videos appear upright. Note I display the video frames using opencv via a while loop :
 cap = cv2.VideoCapture("video.MOV")

  


  ret,frame=cap.read()

  


  while ret:
    cv2.imshow('',frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
    ret,frame = cap.read()
cap.release()
cv2.destroyAllWindows() 


  


  This is not the problem. The problem is that when the same video is run on another machine with the same os and same virtual environment, the videos come out rotated by 90 degrees. Any reason this should happen ?

  


  Both machines are using opencv-python version 4.5.1, ffmpeg 4.2.2, and ffmpeg-python 0.2.0.

  


• ffmpeg - audio is 500ms behind video in screen recording

  3 octobre 2020, par Riz

  I am trying to record my screen along with the audio using ffmpeg 4.3. But in the final output, my audio is around 500ms to 1sec behind the video. Why is this happening ? How this can be fixed ? Here is the command I am using on Windows 10 machine :

  


  


  ffmpeg.exe -threads 4 -rtbufsize 1024m -f dshow -i audio="Microphone
(Realtek Audio)" -f gdigrab -offset_x 0 -offset_y 0 -video_size
1920x1080 -framerate 30 -probesize 32 -i desktop -pix_fmt yuv420p -c:v
libx264 -crf 28 -preset ultrafast -tune zerolatency -movflags
+faststart test.mp4