Newest 'ffmpeg' Questions - Stack Overflow

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• How to change bitrate mode : VBR to CBR with MPEG4 of H264 file ?

  14 août 2018, par The Bird

  I've tried to convert bitrate mode from VBR to CBR with FFMPEG library,but bitrate mode cannot change. My command line:

  ffmpeg -i -f mpegts -acodec libmp3lame -ar 48000 -ab 64k -s 320×240 -vcodec libx264 -b 96k -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -subq 5 -trellis 1 -refs 1 -coder 0 -me_range 16 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 200k -maxrate 96k -bufsize 96k -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 30 -aspect 320:240 -g 30 -async 2

  I found some apps but don't have any app that i can change bitrate mode. Can anyone point me why my cmd cannot change mode or the app can does that?. I think CBR is a mode that bitrate is the same all time,it's true? Thanks

• What is the difference between these 2 wav files ?

  14 août 2018, par user2276831

  I am trying to use a program called arss to create a spectrogram from a wav file. I have 2 wav files, one works and the other does not (it was converted to wav from mp3).

  The error that arss throws at me is This WAVE file is not currently supported. Which is fine, but I have no idea what parts of my wav file to change so that it will be supported. The docs don't help here (as far as I can tell)

  When I run mediainfo on both wav files, I can the following specs:

  working wav:

  General
  Complete name                            : working.wav
  Format                                   : Wave
  File size                                : 1.15 MiB
  Duration                                 : 6 s 306 ms
  Overall bit rate mode                    : Constant
  Overall bit rate                         : 1 536 kb/s
  
  Audio
  Format                                   : PCM
  Format settings                          : Little / Signed
  Codec ID                                 : 1
  Duration                                 : 6 s 306 ms
  Bit rate mode                            : Constant
  Bit rate                                 : 1 536 kb/s
  Channel(s)                               : 2 channels
  Sampling rate                            : 48.0 kHz
  Bit depth                                : 16 bits
  Stream size                              : 1.15 MiB (100%)
  

  not working wav:

  General
  Complete name                            : not_working.wav
  Format                                   : Wave
  File size                                : 5.49 MiB
  Duration                                 : 30 s 0 ms
  Overall bit rate mode                    : Constant
  Overall bit rate                         : 1 536 kb/s
  Writing application                      : Lavf57.83.100
  
  Audio
  Format                                   : PCM
  Format settings                          : Little / Signed
  Codec ID                                 : 1
  Duration                                 : 30 s 0 ms
  Bit rate mode                            : Constant
  Bit rate                                 : 1 536 kb/s
  Channel(s)                               : 2 channels
  Sampling rate                            : 48.0 kHz
  Bit depth                                : 16 bits
  Stream size                              : 5.49 MiB (100%)
  

  Comparing the audio specs of both files, I can't tell any difference between anything other than the file size and duration. I even updated the Sampling rate of the non-working wav using ffmpeg so that it would match the working one at 48.0kHz, but no luck.

  Any idea?

  Both wav files are avaliable here

• How can I get video size from FFmpegStream

  14 août 2018, par SST

  I am trying to get video metadata from a video using ffmpeg. I am using the following dependency,

  
     net.bramp.ffmpeg
     ffmpeg
     0.6.2
  
  

  I am unable to get the video size using the following code snippet,

          FFprobe ffprobe = new FFprobe();
          FFmpegProbeResult metadata = ffprobe.probe("/tmp/" + filename);
          List streams = metadata.getStreams();
  
          for (FFmpegStream stream : streams) {
              videoProperties.put("bitrate", stream.bit_rate);
              videoProperties.put("frameRate", stream.avg_frame_rate.toString());
              videoProperties.put("size", stream.nal_length_size);
              videoProperties.put("resolution", stream.width + "X" + stream.height);
              videoProperties.put("duration", new Double(stream.duration).toString());
              videoProperties.put("codec", stream.codec_name);
              videoProperties.put("CodecType", stream.codec_type.name());
          }
  

  stream.nal_length_size always returns null. Kindly provide your inputs to get the video size.

  Any inputs here really appreciated!

• Transcoding via FFmpeg. Set starting pcr value

  14 août 2018, par Ivan Kolesnikov

  I transcoding via FFmpeg (video codec - h264, container - MPEG-TS) output writing to local file (out.mpg). When FFmpeg dropped I restarted it with output to the same file (out.mpg). After this my video player shows incorrect file duration due to new FFmpeg process start counting PCR from 0.
  Can I set starting pcr value at start FFmpeg ?

• Rtsp streaming, no live

  14 août 2018, par Alejandro

  i follow this topic for streaming rtsp here now this is my conf in the server : ffmpeg -v info -i rtsp://XXXXX.ddns.net/onvif1 -c:v copy -c:a copy -bufsize 1835k -pix_fmt yuv420p -flags -global_header -hls_time 10 -hls_list_size 6 -hls_wrap 10 -start_number 1 /var/www/html/p433/assets/video/test.m3u8 -loglevel debug

  The client:

  
  
  <script src="https://cdnjs.cloudflare.com/ajax/libs/hls.js/0.10.1/hls.light.min.js"></script>
  
  <script src="https://releases.flowplayer.org/7.2.6/flowplayer.min.js"></script>
  
  
  <script>
  
          flowplayer('#player', {
  
              live: true,  // set if it's a live stream          
  
              ratio: 9/16, // set the aspect ratio of the stream
  
              clip: {
  
                  sources: [
  
                      // path to the HLS m3u8
  
                      { type: "application/x-mpegurl", src: "&lt;?php echo asset_url();?>video/test.m3u8"},
  
                      // path to an optional MP4 fallback
  
                      { type: "video/mp4", src: "//yourserver/path/index.mp4"}
  
                  ]
  
              }
  
          });
  
  </script>
  

  The problem ? dont show video in "Live", only show 20seconds aprox and the video is loop icon loading

  what am I doing wrong? I try it all night but I think that it reaches the point of not finding the right path

  thanks for your time !