Newest 'x264' Questions - Stack Overflow

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• How to use gstreamer to save webcam video to file ?

  21 juin 2017, par sav

  I've been trying to get emgu to save same webcam video to file

  The problem is opencv only ssupports avi, and avi does not seem to suit a format like X264 very well.

  Could I use Gstreamer to do this for me in C?

  It would be good if I could choose the file format and container type too. It would be good if I could use a format like schrodinger dirac.

  I'm new to GStreamer so I'm not quite sure if I'm on the right track here.

  EDIT

  I've managed to capture the webcam video using

  gst-launch-0.10 ksvideosrc ! autovideosink

  Now how to transcode this to a format like H264 or dirac ...?

  EDIT

  gst-launch-0.10 ksvideosrc num-buffers=10 ! decodebin2 ! ffmpegcolorspace ! x264enc ! matroskamux ! filesink location=video.mkv

  This seems to create a file, but VLC player can't read it.

• Ubuntu 16.10 ffmpeg Unknown encoder 'libx264' ，I'm sure I have installed X264

  16 juin 2017, par itgoyo

  

  Ubuntu 16.10 ffmpeg Unknown encoder libx264, I 'm sure I have installed X264

• How to extract 16-bit PNG frame from lossless x264 video

  29 mai 2017, par whiskeyspider

  I encoded a series of 16-bit grayscale PNGs to a lossless video with the following command:

  ffmpeg -i image%04d.png -crf 0 -c:v libx264 -preset veryslow output.mp4
  

  I am now trying to verify that the conversion to video was truly lossless by pulling out the PNGs at the same quality. The command I'm using:

  ffmpeg -i output.mp4 image%04d.png
  

  However, this is outputting 8-bit PNGs. I've tried various options I've read about such as -vcodec png and -qscale 0 but so far nothing appears to make it output 16-bit PNGs.

  How do I extract all frames from the video at the same quality as they were going in? Or did I make a mistake in creating the lossless video in the first place?

  Edit: I get this error message when trying to use -pix_fmt gray16be.

  [swscaler @ 0x7fef1a8f0800] deprecated pixel format used, make sure you did set range correctly

  Full output:

  ffmpeg -i output.mp4 -pix_fmt gray16be  image%04d.png
  ffmpeg version 3.3.1 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/3.3.1 --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. 58.100 / 55. 58.100
    libavcodec     57. 89.100 / 57. 89.100
    libavformat    57. 71.100 / 57. 71.100
    libavdevice    57.  6.100 / 57.  6.100
    libavfilter     6. 82.100 /  6. 82.100
    libavresample   3.  5.  0 /  3.  5.  0
    libswscale      4.  6.100 /  4.  6.100
    libswresample   2.  7.100 /  2.  7.100
    libpostproc    54.  5.100 / 54.  5.100
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf57.71.100
    Duration: 00:00:09.76, start: 0.000000, bitrate: 1337 kb/s
      Stream #0:0(und): Video: h264 (High 4:4:4 Predictive) (avc1 / 0x31637661), yuvj444p(pc), 512x512, 1336 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
      Metadata:
        handler_name    : VideoHandler
  Stream mapping:
    Stream #0:0 -> #0:0 (h264 (native) -> png (native))
  Press [q] to stop, [?] for help
  [swscaler @ 0x7fef1a8f0800] deprecated pixel format used, make sure you did set range correctly
  Output #0, image2, to 'image%04d.png':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf57.71.100
      Stream #0:0(und): Video: png, gray16be, 512x512, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc (default)
      Metadata:
        handler_name    : VideoHandler
        encoder         : Lavc57.89.100 png
  frame=  244 fps=0.0 q=-0.0 Lsize=N/A time=00:00:09.76 bitrate=N/A speed=  21x    
  video:4038kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  

  I'm happy to use a non-ffmpeg solution if there is one.

• How to compile ffmpeg and x264 with thread support for android ?

  18 mai 2017, par Sureshkumar Menon

  i want to compile both x264 and ffmpeg with thread support for ANDROID .FFmpeg and x264 didn't compile with thread support even after enabling enable-pthreads and enable-threads respectively.

  Both the config.h contains #define HAVE_THREAD 0 and #define HAVE_PTHREADS 0

  1.How to compile with thread support. 2.Second question is that when i increase the gop size from 1 to some other value encoder returns 0 for certain subsequent frames.This causes a delay more than 3 to 5 seconds in vide playing

• How to compile ffmpeg and x264 with thread support for android ?

  18 mai 2017, par Sureshkumar Menon

  i want to compile both x264 and ffmpeg with thread support for ANDROID .FFmpeg and x264 didn't compile with thread support even after enabling enable-pthreads and enable-threads respectively.

  Both the config.h contains #define HAVE_THREAD 0 and #define HAVE_PTHREADS 0

  1.How to compile with thread support. 2.Second question is that when i increase the gop size from 1 to some other value encoder returns 0 for certain subsequent frames.This causes a delay more than 3 to 5 seconds in vide playing