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• examples/c/decode/file/main.c : Add extra error handling.

  20 novembre 2014, par Erik de Castro Lopo

  examples/c/decode/file/main.c : Add extra error handling.
  Michele Spagnuolo provided a file that initially had frames with two
  
  channels but then had a frame with a single channel. This example
  
  program only supports exactly two channels and previously had
  
  insufficient validation.
  Closes : https://sourceforge.net/p/flac/bugs/418/
  
  Reported-by : Michele Spagnuolo,
  
               Google Security Team <mikispag@google.com>
  

  • [DH] examples/c/decode/file/main.c

• avutil/log : print level prefix also when no AVClass context is available

  14 mars 2018, par Tobias Rapp

  avutil/log : print level prefix also when no AVClass context is available
  Adds the level prefix to all log messages, except those with level <=
  
  AV_LOG_QUIET as they seem to be used for flushing the log buffer.
  Reviewed-by : Michael Niedermayer <michael@niedermayer.cc>
  
  Signed-off-by : Tobias Rapp <t.rapp@noa-archive.com>
  

  • [DH] libavutil/log.c

• Rotating an MP4 Video at the Packet Level Using FFmpeg's Java CPP Presets and Outputting as M3U8

  16 mars 2023, par Yunus Emre Guney Student

  I'm attempting to rotate an MP4 video at the packet level and output it as an M3U8 using FFmpeg's Java CPP presets. Here's what I've tried :

  


  First, I created a rotationMatrixPointer using an IntPointer and allocated memory for it using avutil.av_malloc(size). Then, I set the display rotation to 90 degrees using avutil.av_display_rotation_set(rotationMatrixPointer, 90).

  


  Next, I created a bytePointer using the rotationMatrixPointer and set its limit to rotationMatrixPointer.sizeof() * rotationMatrixPointer.limit(). I then added side data to the videoPkt using av_packet_add_side_data(videoPkt, AV_PKT_DATA_DISPLAYMATRIX, bytePointer, bytePointer.limit()).

  


  If ret < 0, I print "cannot add side data". Finally, I write the packet using writePacket(videoPkt, (AVCodecContext)null) and release the videoPkt using av_packet_unref(videoPkt).

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  packet level rotation matrix side data hls stream output :

  &#xA;

   IntPointer rotationMatrixPointer = new IntPointer(avutil.av_malloc(size)).capacity(size);
 avutil.av_display_rotation_set(rotationMatrixPointer, 90);
 BytePointer bytePointer = new BytePointer(rotationMatrixPointer);
 bytePointer.limit(rotationMatrixPointer.sizeof() * rotationMatrixPointer.limit());
 int ret = av_packet_add_side_data(videoPkt, AV_PKT_DATA_DISPLAYMATRIX, bytePointer, bytePointer.limit());
        
 if (ret < 0) {
 System.out.println("cannot add side data");
            }
 writePacket(videoPkt, (AVCodecContext)null);
        
 av_packet_unref(videoPkt);


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  Although I'm not getting any errors, the video isn't being rotated. However, if I add the rotation matrix at the stream level and output it as an MP4, it works properly.

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  stream level mp4 to mp4 is working :

  &#xA;

  int size = 9 * Pointer.sizeof(IntPointer.class);
                IntPointer rotationMatrixPointer = new IntPointer(avutil.av_malloc(size)).capacity(size);
                
                avutil.av_display_rotation_set(rotationMatrixPointer, rotation);

                BytePointer bytePointer = new BytePointer(rotationMatrixPointer);
                bytePointer.limit(rotationMatrixPointer.sizeof() * rotationMatrixPointer.limit());
                
                ret = avformat.av_stream_add_side_data(stream, avcodec.AV_PKT_DATA_DISPLAYMATRIX , bytePointer, bytePointer.limit());
                if (ret < 0) {
                }


  &#xA;

  What is the proper way to rotate an MP4 input and output it as an HLS stream (M3U8) at the packet level using FFmpeg ? C++ examples are also acceptable.

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