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• FFmpeg scale 720*1080 video to 720*404, it not effect, it play as 279 × 404,and use ffmpeg -i it shows 720*404

  16 mars 2018, par yue guan

  FFmpeg scale 720*1080 video to 720*404, it not effect, it plays as 279 × 404, and use cmd ffmpeg -i scaled.mp4 it shows 720*404.
  Then I use cmd ffmpeg -i scaled.mp4 -y -f image2 -ss 1 -vframes 1 ./xx.jpg to get the thumbnail, but I got the size is 720*404.
  Why ?
  and How can I capture the thumbnail of the video as 279*404 ?
  and How can I scale the video as the size what I defined ?

  the video link :enter link description here

• ffmpeg frame rate issue h264+ass to mkv

  27 juin 2013, par user2529661

  I'm using this command for ffmpeg :

  ffmpeg  -i 1.h264 -i ass1.ass -map 0 -map 1 -c copy test.mkv

  The h264 file is 30 fps... the mkv plays at 25fps so it runs slow

  The h264 come off my hd webcam. If i change the frame rate on the camera to 25 it works fine and 15fps wilk play at high speed. I can force the frame rate ? Every if i need a different command line tool to change it that is acceptable. But if i could fix it form ffmpeg that would be ideal. I'm running the commands from vb.net.

  command output
  
  C:\Record\Normal\2013-06-27>c:\ffmpeg\bin\ffmpeg  -i 1.h264 -i ass1.ass -map 0 -
  
  map 1 -c copy test.mkv
  
  ffmpeg version N-54207-ge59fb3f Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Jun 25 2013 21:55:00 with gcc 4.7.3 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
  
  isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
  
  le-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetyp
  
  e --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --ena
  
  ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
  
  ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libsp
  
  eex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-
  
  amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --
  
  enable-libxvid --enable-zlib
  
    libavutil      52. 37.101 / 52. 37.101
  
    libavcodec     55. 17.100 / 55. 17.100
  
    libavformat    55. 10.100 / 55. 10.100
  
    libavdevice    55.  2.100 / 55.  2.100
  
    libavfilter     3. 77.101 /  3. 77.101
  
    libswscale      2.  3.100 /  2.  3.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Input #0, h264, from '1.h264':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: h264 (Baseline), yuv420p, 1920x1088 [SAR 1:1 DAR 30:17],
  
   25 fps, 25 tbr, 1200k tbn, 50 tbc
  
  Input #1, ass, from 'ass1.ass':
  
    Duration: N/A, bitrate: N/A
  
      Stream #1:0: Subtitle: ssa
  
  File 'test.mkv' already exists. Overwrite ? [y/N] y
  
  Output #0, matroska, to 'test.mkv':
  
    Metadata:
  
      encoder         : Lavf55.10.100
  
      Stream #0:0: Video: h264 (H264 / 0x34363248), yuv420p, 1920x1088 [SAR 1:1 DA
  
  R 30:17], q=2-31, 25 fps, 1k tbn, 1200k tbc
  
      Stream #0:1: Subtitle: ssa
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
    Stream #1:0 -> #0:1 (copy)
  
  Press [q] to stop, [?] for help
  
  frame=  144 fps=0.0 q=-1.0 Lsize=    2451kB time=00:00:05.72 bitrate=3509.6kbits
  
  /s
  
  video:2447kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.125529%

• Tools for investigating video corruption — ffmpeg / libavcodec

  11 juillet 2013, par Gopherkhan

  In my current work I'm trying to encode some images to h264 video using the FFMPEG's C library. The resulting video plays fine in VLC, but has no preview image. The video can play in VLC and Mplayer on ubuntu, but won't play on Mac or PC (in fact, it causes a "VTDecoderXPCService quit unexpectedly" error on Mac).

  If I run the resulting file through FFMPEG using the command line, the resulting file has a preview image, and plays correctly everywhere.

  Apparently the file that I get out of the program is corrupt in some weird place, but I don't have any output during my compilation or run to indicate where. I can't share my code at the moment (work code isn't open source yet :-( ), but I have tried a number of things :

  1. Writing only header and trailer data (av_write_trailer) and no frames
  2. writing frames only minus the trailer (using avcodec_encode_video2 and av_write_frame)
  3. Adjusting our time_base and frame pts values to encode only one frame per second
  4. Removing all variable frame rate code
  5. Numerous other variants that I won't bother you with here

  In creating my project, I've also followed the following tutorials :

  • Dr. Anger's FFMPEG tutorial
  • FFmpeg's Own Tutorials
  • An older tutorial from FFmpeg

  And consulted the deprecated ffmpeg functions list

  And compiled FFMPEG on ubuntu according to the official doc

  But every run of the program runs into the exact same problem.

  My question is, is there anything obvious that causes a programmatic run of FFMpeg to differ from a console run (e.g., an incomplete finalization, some threading issues, etc.) ? Like some obvious reason that a console run could repair a corrupted file ? Or is there a decent tool/method for inspecting a video file and finding the point of corruption ?