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• RTSP to file using IMediaTools errors

  4 décembre 2014, par predy23

  Im trying to save a streaming with RTSP to file with IMediaTools. If I use the local file path of the video in the IMediaReader, it goes nice without errors, but if i make a RTSP streaming of the video and I use the RTSP direction in the IMediaReader i have a lot of errors like this one :

  ERROR org.ffmpeg - [h264 error while decoding MB 50 44, bytestream (td)

  I can open the output file but it have a lot of blurry zones and its not smooth.

  This is my code :

      public static void main(String[] args)  {
  
      // TODO code application logic here
  
     //create a media reader
  
      System.out.println("starting video conversion..");
  
  
  
      // create a media reader
  
      IMediaReader reader = ToolFactory.makeReader(inputFilename);
  
      IMediaWriter writer = ToolFactory.makeWriter(outputFilename, reader);
  
  
  
      // add a debug listener to the writer to see media writer events
  
      writer.addListener(ToolFactory.makeDebugListener());
  
      reader.addListener(writer);
  
  
  
      // read and decode packets from the source file and
  
      // and dispatch decoded audio and video to the writer
  
      while (true) {
  
          if (reader.readPacket() != null) {
  
  
  
              break;
  
          }
  
      }
  
  
  
      reader.close();
  
      writer.close();
  
      System.out.println("video conversion finished..");
  
  }

• FFmpeg export codec not supported by Samsung

  21 juillet 2021, par Coski

  I am using FFmpeg to render videos (concatenating image files with audio and then applying speed and volume filters) to export videos to upload to TikTok. As a result, I must first move the videos to my phone.

  


  I do not understand why my phone (S20) will happily play one of the videos (codec information pictured first), but presents an error "Codec not supported" when playing the other (information second).

  


  

  


  

  


  The codec information is from VLC, and as you can see, both videos have identical Codecs (H264-MPEG4).

  


  From analysing the information, the only conclusion I come to is that it has something to do with the fact that the "Decoded Format" differs across the videos. How can I change my export command on the latter so my phone supports the codec ?

  


  CONCATENATION CODE
ffmpeg -f concat -safe 0 -i {path_temp}\\clips.txt -c copy -y "{path_temp}\\{title}_a.mp4

  


  FILTER CODE
ffmpeg -i input.mp4 -filter:a "volume={volume}" -y temp.mp4"

  


  SECOND FILTER
ffmpeg -i temp.mp4 -filter_complex "[0:v]setpts={1/speed}*PTS[v];[0:a]atempo={speed}[a]" -map "[v]" -map "[a]" -y output.mp4

  


• lavc/opusdsp : RISC-V V (512-bit) postfilter

  5 octobre 2022, par Rémi Denis-Courmont

  lavc/opusdsp : RISC-V V (512-bit) postfilter
  This adds a variant of the postfilter for use with 512-bit vectors.
  
  Half a vector is enough to perform the scalar product. Normally a whole
  
  vector would be used anyhow. Indeed fractional multiplers are no faster
  
  than the unit multipler.
  But in this particular function, a full vector makes up 16 samples,
  
  which would be loaded at each iteration of the outer loop. The minimum
  
  guaranteed CELT postfilter period is only 15. Accounting for the edges,
  
  we can only safely preload up to 13 samples.
  The fractional multipler is thus used to cap the selected vector length
  
  to a safe value of 8 elements or 256 bits.
  Likewise, we have the 1024-bit variant with the quarter multipler. In
  
  theory, a 2048-bit one would be possible with the eigth multipler, but
  
  that length is not even defined in the specifications as of yet, nor is
  
  it supported by any emulator - forget actual hardware.
  

  • [DH] libavcodec/riscv/opusdsp_init.c
  • [DH] libavcodec/riscv/opusdsp_rvv.S