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• ffmpeg : concat videos and images

  23 mai 2016, par Yosko

  I have 2 videos (same resolution, same encoding) files that I want to concat and I want to insert some text for 3 seconds between them, as a splitter. I’m doing this with ffmpeg on Windows.

  Optional ideas that I would be interested in :

  • avoid reencoding the video in the process
  • having a fade in / fade out at the intersection of each part

  For now, I made the text as an image (but I am open to other suggestions). Let’s say I have :

  • video1.mp4 : 6:33
  • splitter.png (same resolution as video1.mp4)
  • video2.mp4 : 16:44

  I have tried a few things, but I always end up with the same problem : the video is 23:20 (video1 + 3 seconds + video2), but the 3 seconds gap is just the last video1 frame frozen instead of my image/text...

  Any Idea what I did wrong or how I should achieve this ?

  Here is what I tried so far :

  Method 1 : image to video

  Turn the image into a 3 seconds mp4 film, then concat (demuxer) it with the others :

  ffmpeg -loop 1 -f image2 -i splitter.png -r 30 -t 3 splitter.mp4
  
  ffmpeg -f concat -i input.txt -codec copy output.mp4

  Where the input.txt looks like :

  file 'E:\video1.mp4'
  
  file 'E:\splitter.mp4'
  
  file 'E:\video2.mp4'

  The content of splitter.png is visible in the splitter.mp4, but not in the output.mp4. Also I’m not entirely sure the splitter.mp4 respects the exact same encoding as the 2 videos, and I don’t know how to verify that.

  Method 2 : insert image frames

  Directly run the concat (demuxer) 90 times (30fps -> 3 seconds) on the image

  ffmpeg -f concat -i input.txt -codec copy output.mp4

  Where the input.txt looks like :

  file 'E:\video1.mp4'
  
  file 'E:\splitter.png'
  
  ...
  
  file 'E:\splitter.png'
  
  file 'E:\video2.mp4'

  Edit : possible solution ?

  Since all I’m doing is screencasting, I might as well screencast my splitter image. This way I would be sure of the audio & video encoding and wouldn’t have any problem merging and it wouldn’t need any reencoding... I know it might sound dumb, but it would probably do the trick...

  Note : I didn’t have try it, since I already worked through Openshot.

• x264 on Ubuntu video bad/corrupted

  6 septembre 2013, par Ryzone

  I am trying to use command line x264 to produce a blu-ray compatible file for use in Adobe Encore. For the source file I've tried both ProRes and mpeg2, both 1080p24. Both files import into Encore fine (no transcoding needed which is great) but the ProRes version is pink and grey "static" and the mpeg2 is just a bunch of green/black lines. The exact same files and the exact same commands on my Win7 PC come out fine. I'm only doing a 10 sec sample of the complete 90min movie. I'd love for it to work on Ubuntu cause it is running a new i7 haswell that encodes much quicker than my PC (many hours difference in encoding time)

  Ubuntu 13.04
  
  
  
  x264 0.135.2 f0c1c53<br />
  
  built on Jul 24 2013, gcc: 4.7.3<br />
  
  configuration: --bit-depth=8 --chroma-format=all<br />
  
  x264 license: GPL version 2 or later
  
  
  
  command:
  
      x264 --bitrate 30000 --preset veryslow --tune film --bluray-compat --fps 24000/1001 --force-cfr --bframes 3 --ref 4 --muxer raw --no-weightb --weightp 0 --b-pyramid none --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --profile high --keyint 24 --min-keyint 1 --open-gop --slices 4 --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1  -o output.264 --input-res 1920x1080 sample.mov

  (if it would work I'd be doing two pass encoding)

  I am able to encode the sample file with ffmpeg to h264 (if that helps).

• ffmpeg not finding audio streams ?

  24 septembre 2013, par Jim Miller

  I'm doing some video conversion with ffmpeg v. N-54271-g7f866c1 (a fresh pull from the git sources in late June 2013) on Fedora 19. One of the things I want to do is to concatenate two videos and then convert the result to an mp4. The following code is working well for me :

  ffmpeg -i video_a.mov -i video_b.mov -acodec libfaac -vcodec libx264 
  
       -preset fast -crf 22  -s 940x528 -pix_fmt yuv420p 
  
       -filter_complex '[0:1] [0:0] [1:1] [1:0]  concat=n=2:v=1:a=1 [v] [a]' 
  
       -map '[v]' -map '[a]' output.mp4

  except for a couple of older hunks of test video I've been using. On those, ffmpeg isn't finding the audio stream, and so the above call dies with ffmpeg complaining that Stream specifier ':1' in filtergraph description [0:1][0:0][1:1][1:0] concat=n=2:v=1:a=1 [v] [a] matches no streams. The catch, of course, is that there is an audio stream in the video ; it's just not getting found.

  When ffmpeg starts, I get a description of the input like so :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/priv/videorising7/raw_take_video/v2261-MTQxMzgwMDM4NzAx.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      creation_time   : 2011-10-13 16:08:18
  
    Duration: 00:00:25.52, start: 0.000000, bitrate: 49 kb/s
  
      Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 608x342, 47 kb/s, 10.03 fps, 10 tbr, 1k tbn, 2k tbc
  
      Metadata:
  
        creation_time   : 2011-10-13 16:08:18
  
        handler_name    : Apple Alias Data Handler

  I suppose the video might just be so old (2006 ?) that I should be lucky that it plays at all. However, I'm able to run these videos through some other ffmpeg jobs (converting from .mov to .mp4, for instance), but those don't require explicitly referencing the audio and video tracks. Any insights out there ?