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• What ffmpeg settings to ensure 0 duplicate frames and 0 dropped frames when capturing to mpeg-2 program stream using ffmpeg/avfoundation on Mac ?

  16 février 2017, par aerodavo

  I’m trying to capture to a DVD compliant mpeg-2 file (ffmpeg : -target ntsc-dvd) from the HDMI output of a camcorder into a Magewell HDMI to USB 3.0 box into my Late 2012 15" non-retina MacBook Pro (quad core 2.3, 16gb ram, ssd), using ffmpeg/avfoundation.

  I’ve tried everything I can think of, or find online. I’m still getting duplicate and dropped frames, which either leads to audio/video sync issues, or audio dropouts, especially for longer recordings. I need this to be stable for recordings of up to 2.5 hours. This is the Terminal output for a 1.5 hour recording :

  Lapaki:~ Lapaki$ /Users/Lapaki/Desktop/ffmpeg -f avfoundation -video_size 960x540 -pixel_format uyvy422 -framerate ntsc -i "XI:XI" -vf crop=iw-240:ih:120:0 -target ntsc-dvd -aspect 4:3 -q:v 3 -ab 256k /Users/Lapaki/Desktop/FF\ Test/`date +%F`\ `date +%H_%M_%S`.mpg
  
  ffmpeg version 3.2.3-tessus Copyright (c) 2000-2017 the FFmpeg developers
  
    built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
  
    configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopus --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzmq --enable-version3 --disable-ffplay --disable-indev=qtkit --disable-indev=x11grab_xcb
  
    libavutil      55. 34.101 / 55. 34.101
  
    libavcodec     57. 64.101 / 57. 64.101
  
    libavformat    57. 56.101 / 57. 56.101
  
    libavdevice    57.  1.100 / 57.  1.100
  
    libavfilter     6. 65.100 /  6. 65.100
  
    libswscale      4.  2.100 /  4.  2.100
  
    libswresample   2.  3.100 /  2.  3.100
  
    libpostproc    54.  1.100 / 54.  1.100
  
  Input #0, avfoundation, from 'XI:XI':
  
    Duration: N/A, start: 610606.984208, bitrate: N/A
  
      Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 960x540, 29.97 fps, 29.97 tbr, 1000k tbn, 1000k tbc
  
      Stream #0:1: Audio: pcm_f32le, 48000 Hz, stereo, flt, 3072 kb/s
  
  Output #0, dvd, to '/Users/Lapaki/Desktop/FF Test/2017-02-15 17_46_28.mpg':
  
    Metadata:
  
      encoder         : Lavf57.56.101
  
      Stream #0:0: Video: mpeg2video (Main), yuv420p, 720x480 [SAR 8:9 DAR 4:3], q=2-31, 6000 kb/s, 29.97 fps, 90k tbn, 29.97 tbc
  
      Metadata:
  
        encoder         : Lavc57.64.101 mpeg2video
  
      Side data:
  
        cpb: bitrate max/min/avg: 9000000/0/6000000 buffer size: 1835008 vbv_delay: -1
  
      Stream #0:1: Audio: ac3, 48000 Hz, stereo, fltp, 256 kb/s
  
      Metadata:
  
        encoder         : Lavc57.64.101 ac3
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo (native) -> mpeg2video (native))
  
    Stream #0:1 -> #0:1 (pcm_f32le (native) -> ac3 (native))
  
  Press [q] to stop, [?] for help
  
  [swscaler @ 0x7fd315892800] Warning: data is not aligned! This can lead to a speedloss
  
  frame=   20 fps=0.0 q=3.0 size=     298kB time=00:00:00.65 bitrate=3721.4kbits/sframe=   35 fps= 35 q=3.0 size=     498kB time=00:00:01.13 bitrate=3591.2kbits/sframe=   50 fps= 33 q=3.0 size=     708kB time=00:00:01.64 bitrate=3519.4kbits/sframe=   65 fps= 32 q=3.0 size=     920kB time=00:00:02.16  
  
  ...
  
   bitrate=2721.7kbits/frame=162094 fps= 30 q=3.0 size= 1796936kB time=01:30:08.47 bitrate=2721.7kbits/frame=162109 fps= 30 q=3.0 size= 1797142kB time=01:30:08.98 bitrate=2721.8kbits/frame=162110 fps= 30 q=3.0 Lsize= 1797202kB time=01:30:09.01 bitrate=2721.9kbits/s dup=221 drop=0 speed=   1x    
  
  video:1579050kB audio:168069kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.866632%

  I deleted the middle part (denoted by the "..."), which is just a lot more of the same accumulating information. By the end there are 221 duplicate frames, and for this one I didn’t get any dropped frames, but that happens every other time as well it seems.

  With this code, the audio seems to stay in pretty good sync, but I get little dropouts every 30 seconds to a minute or so. On this recording, there are dropouts at :

  00:00:43, 00:01:19, 00:01:47, 00:02:17, 00:03:18, ...

  I stopped listening there ; they happen at the end too, so I assume similarly spaced dropouts are happening throughout the file.

  Is there some secret ffmpeg code to ensure there are no dropped or duplicate frames when capturing from a live source to dvd compliant mpeg-2 files ?

  When I convert from pretty much any type of file to mpeg-2 files using -target ntsc-dvd, the speed is something like 10x on this machine, so it seems like it would have no problem keeping up with a live source, right ?

  I’ve also tried constant bit rate using -b:v 5000k -minrate 5000k -maxrate 5000k -bufsize 2500k, which also doesn’t prevent dropped/duplicate frames.

  I’ve tried separating out the audio and video inputs, which doesn’t solve it.

  I’ve tried using -vsync 0 on the video input, which does seem to solve the issue, because the output doesn’t report dups/drops, but the audio/video drift out of sync more and more, so that hasn’t worked either.

  Thanks so much for any help. I’ve been testing and testing and searching and searching for weeks...

• Merge video with ffmpeg

  17 mars 2017, par Björn

  I have tried this command :
  ffmpeg -i 'concat:10.mov|11.mov' -codec copy out.mov
  The output file out.mov only shows whats in the first movie (10.mov).

  Been googling for several hours and tried lots of things but nothing works. I want this done without re-encoding the files. Just merge with the same codec

  ffmpeg version 3.2.4 Copyright (c) 2000-2017 the FFmpeg developers
 built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
 configuration: --prefix=/usr/local/Cellar/ffmpeg/3.2.4 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
 libavutil      55. 34.101 / 55. 34.101
 libavcodec     57. 64.101 / 57. 64.101
 libavformat    57. 56.101 / 57. 56.101
 libavdevice    57.  1.100 / 57.  1.100
 libavfilter     6. 65.100 /  6. 65.100
 libavresample   3.  1.  0 /  3.  1.  0
 libswscale      4.  2.100 /  4.  2.100
 libswresample   2.  3.100 /  2.  3.100
 libpostproc    54.  1.100 / 54.  1.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7ff678802600] Found duplicated MOOV Atom. Skipped it
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'concat:10.mov|11.mov':
 Metadata:
   creation_time   : 2017-03-17T12:15:22.000000Z
   major_brand     : qt<br />
   minor_version   : 537134592
   compatible_brands: qt<br />
 Duration: 00:00:29.96, start: 0.000000, bitrate: 140810 kb/s
   Stream #0:0: Video: prores (apcn / 0x6E637061), yuv422p10le, 1280x720, 116735 kb/s, SAR 1:1 DAR 16:9, 50 fps, 50 tbr, 5k tbn, 5k tbc (default)
   Metadata:
     handler_name    : Telestream Inc. Telestream Media Framework - Local 99.99.999999
     encoder         : Apple ProRes 422
Output #0, mov, to 'out.mov':
 Metadata:
   compatible_brands: qt<br />
   major_brand     : qt<br />
   minor_version   : 537134592
   encoder         : Lavf57.56.101
   Stream #0:0: Video: prores (apcn / 0x6E637061), yuv422p10le, 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 116735 kb/s, 50 fps, 50 tbr, 10k tbn, 5k tbc (default)
   Metadata:
     handler_name    : Telestream Inc. Telestream Media Framework - Local 99.99.999999
     encoder         : Apple ProRes 422
Stream mapping:
 Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
frame= 1498 fps=0.0 q=-1.0 Lsize=  426938kB time=00:00:29.94 bitrate=116815.8kbits/s speed=50.8x<br />
video:426930kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.001997%

  Any ideas ? Would make my life very much easier if I got this to work :)

• Best way to extract all keyframes from a video in Java ?

  2 mars 2017, par JT J

  I have a Windows batch script that I’m currently trying to recreate in Java. The script runs an ffmpeg command that extracts all of the keyframes from a video and pastes them as .BMP images in a folder.

  This is what it the script looks like :

  ffmpeg -i input.mp4 -vf "select=eq(pict_type\,I)" -vsync 1 %%3d.bmp

  The end result of this is that it takes "input.mp4" and outputs each keyframe as 001.bmp, 002.bmp... and so on.

  I’m trying to avoid simply starting an ffmpeg runtime, because I want to be able to run this script on other platforms in the future. Also, I’ll be doing this for very long videos (multiple hours long sometimes) so performance is very important, and needs to be done as fast as possible. Is it possible to use multithreading ? That’s something I’m not familiar with in Java. What would be the best way to do this ?