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• avformat/siff : Basic pkt_size check

  11 juillet 2024, par Michael Niedermayer

  avformat/siff : Basic pkt_size check
  Fixes : half of CID1258461 Overflowed constant
  Sponsored-by : Sovereign Tech Fund
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/siff.c

• Cropping android video reducing its quality

  8 août 2015, par Muhammad Umar

  I am trying to encode a video in Android with ffmpeg.

  Here is the code :

  mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT);
  
  mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
  
  mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
  
  mMediaRecorder.setVideoEncodingBitRate(1024 * 1000);
  
  mMediaRecorder.setVideoFrameRate(30);
  
  mMediaRecorder.setVideoSize(720, 480);
  
  mMediaRecorder.setOrientationHint(90);
  
  mMediaRecorder.setOutputFile(VIDEO_PATH_NAME);

  FFMPEG command :

  buffer.append("ffmpeg -i /storage/emulated/0/file.mp4 -filter:v \"crop=480:480:0:0\" -preset ultrafast -r 30 /storage/emulated/0/cropped.mp4 -movflags faststart");

  The cropped file is twice the size of original file and half the quality . What is going on ? How can I make it lossless

• Convert streaming MPEG-4 raw data to H.264

  16 août 2012, par Jonathan Hawkes

  I've got a Sony network camera (SNC-RZ25N) that I am trying desperately to get data from in some meaningful format. The documentation says it sends MPEG-4 raw data, but is not more specific than than. I can capture a segment of the stream using curl ( http://techhead.biz/media/tsv.m4v ) and it will play using VLC and ffplay (though it plays too fast in ffplay).

  After a day and a half of tinkering, I just discovered that I cannot use ffmpeg to convert this stream directly. For one, the only way ffmpeg accepts piped data as input (that I'm aware of) is in the 'yuv4mpegpipe' format.

  I tried piping to ffmpeg using 'm4v' as the specified format, but it seems to want to read the entire stream before it begins processing.

  Anyone know how I can do this ? Using commandline tools ? Open source libraries in ANY programming language ? Simpler solutions are preferred, but any working solution would be great.