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• how to reencode with ffmpeg (with limited x264)

  6 septembre 2017, par Sarfraz

  Until now I used this script to reencode my rips for my box (tv decoder) :

  ^_^ ( ~ ) -> cat ~/++/src/convert.sh 
  
  #! /bin/bash
  
  
  
  name=$(path -r "$1") # it gives the file name without the extension
  
  
  
  [ "$1" = *.mp4 ] && ffmpeg -i "$name".mp4 -vcodec copy -acodec copy "$name".mkv
  
  x264 --preset veryfast --tune animation --crf 18 --vf resize:720,576,16:15 -o "$name".tmp.mkv "$name".mkv
  
  mkvmerge -o "$name [freeplayer sd]".mkv "$name".tmp.mkv --no-video "$1"
  
  rm -rf "$name".tmp.mkv
  
  [ "$1" = *.mp4 ] && rm -rf "$name".mkv
  
  exit 0
  
  
  
  #EOF

  It works on my ubuntu and archlinux laptops. But it doesn’t on my desktop witch runs fedora.
  Google says that the x264 package shiped by rpmfusion doesn,t support lavf and ffms2.
  And I cannot unistall it because smplayer (witch i like) needs it.

  Ok, so I have to compile it. Google then says "you have to build ffmpeg, ffms2 tnen x264 ensuring that the flags are correctly refered." Well, didn’t work (ffms2 cannot find LIBAV - even when I am telling where - and x264 does’t configure with lavf...)

  My question is : can I use ffmpeg alone to do what my script does.
  I have ffmpeg version 0.8.11, x264 0.116.2048 59cb2eb and gcc : 4.6.1 20110804 (Red Hat 4.6.1-7)

  EDIT : Ok, I found that : ffmpeg -i input file -acodec copy -vcodec libx264 -preset veryfast -tune animation [that part I don’t have] output

• Streaming video (C# using FFmpeg AutoGen) sends multiple data requests

  14 juillet 2016, par williamtroup

  I’ve written a video generator that rights a video in h264 format (mp4). When I stream the video from my azure service, i’m seeing the following network traffic :

  

  The AVCodecContext layout I’m using is as follows :

  AVCodec* videoCodec = ffmpeg.avcodec_find_encoder(AVCodecID.AV_CODEC_ID_H264)
  
  AVCodecContext* videoCodecContext = ffmpeg.avcodec_alloc_context3(videoCodec);
  
  videoCodecContext->bit_rate = 400000;
  
  videoCodecContext->width = 1280;
  
  videoCodecContext->height = 720;
  
  videoCodecContext->gop_size = 12;
  
  videoCodecContext->max_b_frames = 1;
  
  videoCodecContext->pix_fmt = videoCodec->pix_fmts[0];
  
  videoCodecContext->codec_id = videoCodec->id;
  
  videoCodecContext->codec_type = videoCodec->type;
  
  videoCodecContext->time_base = new AVRational
  
  {
  
      num = 1,
  
      den = 30
  
  };
  
  
  
  ffmpeg.av_opt_set(videoCodecContext->priv_data, "preset", "ultrafast");

  I’m also tried setting the "movflags" option for avformat_write_header() via an AVDictionary, but then av_write_trailer() returns -2, cause the file to not finish writing.

  I cannot figure out how to solve this problem. Videos generating using Windows Movie Maker stream perfectly.

  I know this has something to do with mdat and mov positions.

  Also, this appears to only happening in Google Chrome.

• Trim / Cut video on Android using FFMpeg's Copy

  6 août 2012, par Kevin P

  We're trying to replicate the functionality of this command line ffmpeg directive using the FFMpeg c api through JNI calls on Android.

  ffmpeg -ss 2 -t 120 -vcodec copy -acodec copy -i input.file output.file

  Basically, given a start and end time, we wish to copy (not re-encode) a small(er) segment of video from the larger (input) video source.

  We've been using the wonderful JavaCv wrapper to openCv and FFMpeg, but we just cannot figure out how to do this simple bit of work. We've been scouring the ffmpeg.c and related sources and while I now understand that it switches to stream_copy and remuxing rather than re-encoding when the codec is specified as copy I cannot for the life of me identify what series of method calls to make to replicate this through the C api. Does anyone have an example JNI file for doing this ? Or are there rockstar C types that can explain how I get from that command line to api calls ? We've spent the better part of two weeks working on this (we're not native C guys) and we're at the point where we just need to ship some code. Any example code, especially JNI code or method call maps etc. would be greatly appreciated !