Recherche avancée

Sur d’autres sites (3921)

• How to concatenate two videos w. ffmpeg — documented code not working

  2 mars 2014, par Jim Miller

  I'm trying to concatenate two videos with ffmpeg. Nothing fancy ; I just want one video that consists of video A immediately followed by video B.

  I've tried the code from How to concatenate (join, merge) media files on a freshly built and otherwise-working-fine install of ffmpeg 1.2.1 on Fedora 17, but the following error message appears :

  $ ffmpeg -i video_a.mov -i video_b.mov -filter_complex '[0:0] [0:1] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a]' -map '[v]' -map '[a]' output.mp4
  
  
  
  ffmpeg version N-54271-g7f866c1 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Jun 29 2013 11:05:42 with gcc 4.7.2 (GCC) 20120921 (Red Hat 4.7.2-2)
  
    configuration: --enable-gpl --enable-nonfree --enable-pthreads --enable-libx264 --enable-libfaac --extra-cflags=-I/usr/local/include --extra-ldflags=-L/usr/local/lib
  
    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, mov,mp4,m4a,3gp,3g2,mj2, from 'v1221-MTQxMzcyNTIxODU2.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2013-03-28 20:34:59
  
      encoder         : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
      encoder-eng     : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
    Duration: 00:00:05.34, start: 0.000000, bitrate: 15837 kb/s
  
      Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 221 kb/s
  
      Metadata:
  
        creation_time   : 2013-03-28 20:34:59
  
        handler_name    : Core Media Data Handler
  
      Stream #0:1(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 15512 kb/s, 29.81 fps, 30 tbr, 600 tbn, 1200 tbc
  
      Metadata:
  
        creation_time   : 2013-03-28 20:34:59
  
        handler_name    : Core Media Data Handler
  
  
  
  Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'v1224-MTQxMzcyNTIxODg5.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2013-03-28 20:36:28
  
      encoder         : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
      encoder-eng     : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
    Duration: 00:00:04.13, start: 0.000000, bitrate: 15689 kb/s
  
      Stream #1:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 221 kb/s
  
      Metadata:
  
        creation_time   : 2013-03-28 20:36:28
  
        handler_name    : Core Media Data Handler
  
      Stream #1:1(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 15446 kb/s, 29.79 fps, 30 tbr, 600 tbn, 1200 tbc
  
      Metadata:
  
        creation_time   : 2013-03-28 20:36:28
  
        handler_name    : Core Media Data Handler
  
  
  
  Stream specifier ':0' in filtergraph description [0:0] [0:1] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a] matches no streams.

  A few other things to note :

  • The two videos I'm working with were shot with the same camera, so there shouldn't be any problems with aspect ratio or other gory video details.
  • I'm able to do other things with my ffmpeg installation, like convert one of those videos from .mov to .mp4 (yes, I had to recompile with faac...), which seems to vouch for both the ffmpeg and the video.
  • I've tried modifying the above invocation to produce a .mov file at the end, but I get the same error as before.
  • I've tried some stupid hacking tricks on the request above, like concatenating two copies of the same video, as well as some other invocations from other places around the web that involve filter_complex. Even on ones that were cited as working, I get the "matches no streams" message.

• Improve FFmpeg time ? conversion takes very long

  15 avril 2015, par Rubytastic

  I have several rules to convert a movie to several formats and create a preview image. Problem is the execution of these takes very long.
  Also the outputted quality is very low. I harvested these examples from several sources.

  What could be done to
  * improve speed
  * improve quality ?

   ffmpeg -y -i /file/$1.flv -acodec libmp3lame -ar 44100 -ac 1 -vcodec libx264 /file/$1.mp4
  
   ffmpeg -i /file/$1.mp4 -acodec libvorbis -aq 5 -ac 2 -qmax 25 -threads 2 /file/$1.webm
  
   ffmpeg -r 30 -i /file/$1.mp4  -vcodec libtheora -acodec libvorbis /file/$1.ogv
  
   ffmpeg -i /file/$1.mp4 -ss 3 -f image2 -vframes 1 -s 600x480 /file/$1.png

• dxva2_h264 : fix slice offset in long slice structs

  23 mars 2015, par Hendrik Leppkes

  dxva2_h264 : fix slice offset in long slice structs
  

  • [DH] libavcodec/dxva2_h264.c