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• Is it possible to merge 3 videos with ffmpeg by -f concat and crossfade without video content

  10 août 2019, par user3792705

  I want to merge 3 .mov files quickly without losing any resolution. I want to be able to distinguish the 3 pieces of videos after merge.

  "ffmpeg -f concat" does not lose resolution and quick without crossfade.

  But, I can’t distinguish 3 videos.

  As far as I know ffmpeg filter can be used add crossfade, but it have to use video start/end content to do the merger, which might involve transcoding. It won’t be fast compared with ’concat’, which won’t do transcoding, but simply copying.

  Here is the content (ffmpeg -i video.mov) of one of 3 videos :

  ffmpeg version 4.1.3 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with Apple LLVM version 10.0.1 (clang-1001.0.46.3)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.3 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/openjdk-12.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/openjdk-12.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
  
    libavutil      56. 22.100 / 56. 22.100
  
    libavcodec     58. 35.100 / 58. 35.100
  
    libavformat    58. 20.100 / 58. 20.100
  
    libavdevice    58.  5.100 / 58.  5.100
  
    libavfilter     7. 40.101 /  7. 40.101
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '..../(edited)/VMEK8375.MOV':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2019-06-30T01:28:04.000000Z
  
      com.apple.quicktime.model: iPhone
  
      com.apple.quicktime.software: ZHIYUN
  
      com.apple.quicktime.creationdate: 2019-06-30T09:28:04Z
  
    Duration: 00:00:07.61, start: 0.000000, bitrate: 4386 kb/s
  
      Stream #0:0(und): Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv, smpte170m/bt709/bt709), 1280x720, 4329 kb/s, 30.01 fps, 30 tbr, 600 tbn, 600 tbc (default)
  
      Metadata:
  
        creation_time   : 2019-06-30T01:28:04.000000Z
  
        handler_name    : Core Media Video
  
        encoder         : HEVC
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 94 kb/s (default)
  
      Metadata:
  
        creation_time   : 2019-06-30T01:28:04.000000Z
  
        handler_name    : Core Media Audio

  If I don’t care about crossfade with video content, just some ’nice’ black screen in between (It would be nice I add some text, like date + time on the black screen) is good enough for me. Is it possible to do ’concat’ and simple crossfade without video ’content’ ?

• My FFMPEG converter is not allowing mp4 to webm conversions.

  2 novembre 2016, par Fred Garbutt

  heres the command :

  ffmpeg -i videos/test.mp4 -c:v libvpx -level 216 -profile 0 -qmax 42 -qmin 10 -c:a libvorbis -f webm out.webm

  i keep getting this error :

  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  here is the full response

  # ffmpeg -i videos/test.mp4 -c:v libvpx -level 216 -profile 0 -qmax 42 -qmin 10 -c:a 
  
  
  
  libvorbis -f webm out.webm
  
  ffmpeg version N-49225-g7e059c9 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Jan 24 2013 05:14:06 with gcc 4.1.2 (GCC) 20080704 (Red Hat 4.1.2-54)
  
    configuration: --enable-version3 --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvpx --enable-libfaac --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-gpl --enable-postproc --enable-nonfree
  
    libavutil      52. 15.101 / 52. 15.101
  
    libavcodec     54. 90.100 / 54. 90.100
  
    libavformat    54. 61.104 / 54. 61.104
  
    libavdevice    54.  3.102 / 54.  3.102
  
    libavfilter     3. 33.100 /  3. 33.100
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  2.100 / 52.  2.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'videos/test.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 1
  
      compatible_brands: mp42avc1
  
      creation_time   : 2010-08-12 15:42:21
  
    Duration: 00:00:34.20, start: 0.000000, bitrate: 358 kb/s
  
      Stream #0:0(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 100 kb/s
  
      Metadata:
  
        creation_time   : 2010-08-12 15:42:21
  
        handler_name    : Apple Sound Media Handler
  
      Stream #0:1(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 640x320, 251 kb/s, 29.97 fps, 29.97 tbr, 2997 tbn, 5994 tbc
  
      Metadata:
  
        creation_time   : 2010-08-12 15:42:21
  
        handler_name    : Apple Video Media Handler
  
  Please use -profile:a or -profile:v, -profile is ambiguous
  
  File 'out.webm' already exists. Overwrite ? [y/N] y
  
  v0.9.6
  
  [libvpx @ 0x7e38d20] Failed to initialize encoder: ABI version mismatch
  
  Output #0, webm, to 'out.webm':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 1
  
      compatible_brands: mp42avc1
  
      Stream #0:0(eng): Video: vp8, yuv420p, 640x320, q=10-42, 200 kb/s, 90k tbn, 29.97 tbc
  
      Metadata:
  
        creation_time   : 2010-08-12 15:42:21
  
        handler_name    : Apple Video Media Handler
  
      Stream #0:1(eng): Audio: none, 44100 Hz, stereo, fltp
  
      Metadata:
  
        creation_time   : 2010-08-12 15:42:21
  
        handler_name    : Apple Sound Media Handler
  
  Stream mapping:
  
    Stream #0:1 -> #0:0 (h264 -> libvpx)
  
    Stream #0:0 -> #0:1 (aac -> libvorbis)
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  does anybody have any idea whats going on ? I am completely lost. I have tried so many different commands. converting from mp4 to ogg works fine, and i have had mp4 to webm working before, but i reinstalled ffmpeg to get the mp4 to ogg working and now ive lost my mp4 to webm conversions. >.< this whole installation process is such a damn nightmare. does anyone havea good tutorial for centos installation of ffmpeg that will work for mp4 ogg and webm ? I have used the centos tut that came off of the ffmpeg site, but it failed me. If anyone has any ideas that could point me in the right direction i would much appreciate it !

• How To Play Hardware Accelerated Video on A Mac

  28 mai 2013, par Multimedia Mike — General

  I have a friend who was considering purchasing a Mac Mini recently. At the time of this writing, there are 3 desktop models (and 2 more “server” models).

  
  
  

  The cheapest one is a Core i5 2.5 GHz. Then there are 2 Core i7 models : 2.3 GHz and 2.6 GHz. The difference between the latter 2 is US$100. The only appreciable technical difference is the extra 0.3 GHz and the choice came down to those 2.

  He asked me which one would be able to play HD video at full frame rate. I found this query puzzling. But then, I have been “in the biz” for a bit too long. Whether or not a computer or device can play a video well depends on a lot of factors.

  Hardware Support
  First of all, looking at the raw speed of the general-purpose CPU inside of a computer as a gauge of video playback performance is generally misguided in this day and age. In general, we have a video standard (H.264, which I’ll focus on for this post) and many bits of hardware are able to accelerate decoding. So, the question is not whether the CPU can decode the data in real time, but can any other hardware in the device (likely the graphics hardware) handle it ? These machines have Intel HD 4000 graphics and, per my reading of the literature, they are capable of accelerating H.264 video decoding.

  Great, so the hardware supports accelerated decoding. So it’s a done deal, right ? Not quite…

  Operating System Support
  An application can’t do anything pertaining to hardware without permission from the operating system. So the next question is : Does Mac OS X allow an application to access accelerated video decoding hardware if it’s available ? This used to be a contentious matter (notably, Adobe Flash Player was unable to accelerate H.264 playback on Mac in the absence of such an API) but then Apple released an official API detailed in Technical Note TN2267.

  So, does this mean that video is magically accelerated ? Nope, we’re still not there yet…

  Application Support
  It’s great that all of these underlying pieces are in place, but if an individual application chooses to decode the video directly on the CPU, it’s all for naught. An application needs to query the facilities and direct data through the API if it wants to leverage the acceleration. Obviously, at this point it becomes a matter of “which application ?”

  My friend eventually opted to get the pricier of the desktop Mac Mini models and we ran some ad-hoc tests since I was curious how widespread the acceleration support is among Mac multimedia players. Here are some programs I wanted to test, playing 1080p H.264 :

  • Apple QuickTime Player
  • VLC
  • YouTube with Flash Player (any browser)
  • YouTube with Safari/HTML5
  • YouTube with Chrome/HTML5
  • YouTube with Firefox/HTML5
  • Netflix

  I didn’t take exhaustive notes but my impromptu tests revealed QuickTime Player was, far and away, the most performant player, occupying only around 5% of the CPU according to the Mac OS X System Profiler graph (which is likely largely spent on audio decoding).

  VLC consistently required 20-30% CPU, so it’s probably leveraging some acceleration facilities. I think that Flash Player and the various HTML5 elements performed similarly (their multi-process architectures can make such a trivial profiling test difficult).

  The outlier was Netflix running in Firefox via Microsoft’s Silverlight plugin. Of course, the inner workings of Netflix’s technology are opaque to outsiders and we don’t even know if it uses H.264. It may very well use Microsoft’s VC-1 which is not a capability provided by the Mac OS X acceleration API (it doesn’t look like the Intel HD 4000 chip can handle it either). I have never seen any data one way or another about how Netflix encodes video. However, I was able to see that Netflix required an enormous amount of CPU muscle on the Mac platform.

  Conclusion
  The foregoing is a slight simplification of the video playback pipeline. There are some other considerations, most notably how the video is displayed afterwards. To circle back around to the original question : Can the Mac Mini handle full HD video playback ? As my friend found, the meager Mac Mini can do an admirable job at playing full HD video without loading down the CPU.