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• Encode video using ffmpeg from javacv on Android causes native code crash

  13 décembre 2012, par gtcompscientist

  NOTE : I have updated this since originally asking the question to reflect some of what I have learned about loading live camera images into the ffmpeg libraries.

  I am using ffmpeg from javacv compiled for Android to encode/decode video for my application. (Note that originally, I was trying to use ffmpeg-java, but it has some incompatible libraries)

  Original problem : The problem that I've run into is that I am currently getting each frame as a Bitmap (just a plain android.graphics.Bitmap) and I can't figure out how to stuff that into the encoder.

  Solution in javacv's ffmpeg : Use avpicture_fill(), the format from Android is supposedly YUV420P, though I can't verify this until my encoder issues (below) are fixed.

  avcodec.avpicture_fill((AVPicture)mFrame, picPointer, avutil.PIX_FMT_YUV420P, VIDEO_WIDTH, VIDEO_HEIGHT)

  Problem Now : The line that is supposed to actually encode the data crashes the thread. I get a big native code stack trace that I'm unable to understand. Does anybody have a suggestion ?

  Here is the code that I am using to instantiate all the ffmpeg libraries :

      avcodec.avcodec_register_all();
  
      avcodec.avcodec_init();
  
      avformat.av_register_all();
  
  
  
      mCodec = avcodec.avcodec_find_encoder(avcodec.CODEC_ID_H263);
  
      if (mCodec == null)
  
      {
  
          Logging.Log("Unable to find encoder.");
  
          return;
  
      }
  
      Logging.Log("Found encoder.");
  
  
  
      mCodecCtx = avcodec.avcodec_alloc_context();
  
      mCodecCtx.bit_rate(300000);
  
      mCodecCtx.codec(mCodec);
  
      mCodecCtx.width(VIDEO_WIDTH);
  
      mCodecCtx.height(VIDEO_HEIGHT);
  
      mCodecCtx.pix_fmt(avutil.PIX_FMT_YUV420P);
  
      mCodecCtx.codec_id(avcodec.CODEC_ID_H263);
  
      mCodecCtx.codec_type(avutil.AVMEDIA_TYPE_VIDEO);
  
      AVRational ratio = new AVRational();
  
      ratio.num(1);
  
      ratio.den(30);
  
      mCodecCtx.time_base(ratio);
  
      mCodecCtx.coder_type(1);
  
      mCodecCtx.flags(mCodecCtx.flags() | avcodec.CODEC_FLAG_LOOP_FILTER);
  
      mCodecCtx.me_cmp(avcodec.FF_LOSS_CHROMA);
  
      mCodecCtx.me_method(avcodec.ME_HEX);
  
      mCodecCtx.me_subpel_quality(6);
  
      mCodecCtx.me_range(16);
  
      mCodecCtx.gop_size(30);
  
      mCodecCtx.keyint_min(10);
  
      mCodecCtx.scenechange_threshold(40);
  
      mCodecCtx.i_quant_factor((float) 0.71);
  
      mCodecCtx.b_frame_strategy(1);
  
      mCodecCtx.qcompress((float) 0.6);
  
      mCodecCtx.qmin(10);
  
      mCodecCtx.qmax(51);
  
      mCodecCtx.max_qdiff(4);
  
      mCodecCtx.max_b_frames(1);
  
      mCodecCtx.refs(2);
  
      mCodecCtx.directpred(3);
  
      mCodecCtx.trellis(1);
  
      mCodecCtx.flags2(mCodecCtx.flags2() | avcodec.CODEC_FLAG2_BPYRAMID | avcodec.CODEC_FLAG2_WPRED | avcodec.CODEC_FLAG2_8X8DCT | avcodec.CODEC_FLAG2_FASTPSKIP);
  
  
  
      if (avcodec.avcodec_open(mCodecCtx, mCodec) == 0)
  
      {
  
          Logging.Log("Unable to open encoder.");
  
          return;
  
      }
  
      Logging.Log("Encoder opened.");
  
  
  
      mFrameSize = avcodec.avpicture_get_size(avutil.PIX_FMT_YUV420P, VIDEO_WIDTH, VIDEO_HEIGHT);
  
      Logging.Log("Frame size - '" + mFrameSize + "'.");
  
      //mPic = new AVPicture(mPicSize);
  
      mFrame = avcodec.avcodec_alloc_frame();
  
      if (mFrame == null)
  
      {
  
          Logging.Log("Unable to alloc frame.");
  
      }

  This is what I want to be able to execute next :

      BytePointer picPointer = new BytePointer(data);
  
      int bBuffSize = mFrameSize;
  
  
  
      BytePointer bBuffer = new BytePointer(bBuffSize);
  
  
  
      int picSize = 0;
  
      if ((picSize = avcodec.avpicture_fill((AVPicture)mFrame, picPointer, avutil.PIX_FMT_YUV420P, VIDEO_WIDTH, VIDEO_HEIGHT)) <= 0)
  
      {
  
          Logging.Log("Couldn't convert preview to AVPicture (" + picSize + ")");
  
          return;
  
      }
  
      Logging.Log("Converted preview to AVPicture (" + picSize + ")");
  
  
  
      VCAP_Package vPackage = new VCAP_Package();
  
  
  
      if (mCodecCtx.isNull())
  
      {
  
          Logging.Log("Codec Context is null!");
  
      }
  
  
  
      //encode the image
  
      int size = avcodec.avcodec_encode_video(mCodecCtx, bBuffer, bBuffSize, mFrame);
  
  
  
      int totalSize = 0;
  
      while (size >= 0)
  
      {
  
          totalSize += size;
  
          Logging.Log("Encoded '" + size + "' bytes.");
  
          //Get any delayed frames
  
          size = avcodec.avcodec_encode_video(mCodecCtx, bBuffer, bBuffSize, null); 
  
      }
  
      Logging.Log("Finished encoding. (" + totalSize + ")");

  But, as of now, I don't know how to put the Bitmap into the right piece or if I have that setup correctly.

  A few notes about the code :
  - VIDEO_WIDTH = 352
  - VIDEO_HEIGHT = 288
  - VIDEO_FPS = 30 ;

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  I want to switch videos, while one other playing. When I load new video few times, applicaton crashes, how do it correctly ?

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