Newest 'ffmpeg' Questions - Stack Overflow

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• Mixing 2 audio files

  9 décembre 2011, par Joy

  I have two audio files. I want to mix them together so that when played, they play on top of each other simultaneously.

  Is there any API available that can help me do that?

• normalize volume in audiofile

  9 décembre 2011, par Yanny

  Now I'm creating video with FFMPEG library. I'm receiving audiofile by recording user's voice. How can I normalize sound. Maybe ffmpeg have tools. Or can you recommend you some algorithm for normalization?

• YUY2 image ==>>sws_scale ==>>x264_encoder_encode doesn't work in Windows

  8 décembre 2011, par shiju sasi

  I have a multi media app in Windows using x264 built using MSYS-MingW and ffmpeg Windows binaries. This works for most of the cameras which capture data in RGB24 and RGB32 formats in most of the OSes. But when I tested the app on a Windows 7 (64 bit OS) Sony Vaio Laptop which has an integrated webcam capturing in YUY2 format, the x264_enoder_encode crashes. The sws_scale to convert the YUY2 data to YUV420 Planar any way works fine here too and returns proper stride values. Please check the relevant code fragments that I have attached below.

       x264_param_apply_profile(&m_param, "baseline");
         m_pEncoder = x264_encoder_open(&m_param);
         x264_encoder_parameters(m_pEncoder,&m_param);
  
         m_encoderConvertCtx = sws_getContext(g_iWidth, g_iHeight, PIX_FMT_YUYV422, SCALE_WIDTH, SCALE_HEIGHT, PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
  
         x264_picture_t m_pic_in, m_pic_out;   //X264 picture variables to get the X264 encoded picture out.
         x264_picture_init(&m_pic_in);
   m_pic_in.i_type = X264_CSP_I420;
  
   x264_nal_t*  m_nals;
  
  
   srcstride = g_iWidth * 2;  //For YUYV422 Packed
  
   AVFrame* pictIn;
   AVFrame* pictOut;
  
   int iInBytes = avpicture_get_size(PIX_FMT_YUV420P, SCALE_WIDTH, SCALE_HEIGHT); 
   uint8_t* outbuffer = (uint8_t*)av_malloc(iInBytes); 
   pictOut = avcodec_alloc_frame(); 
  
   avpicture_fill((AVPicture*)pictOut, outbuffer, PIX_FMT_YUV420P, SCALE_WIDTH, SCALE_HEIGHT); 
  
   sws_scale(m_encoderConvertCtx, &in_buf, &srcstride, 0, g_iHeight, pictOut->data, pictOut->linesize); //Scale from YUYV422 Packed to YUV420 Plane
  
  
  ///Code after Scale begins
  
  memcpy(m_pic_in.img.plane[0],pictOut->data[0],SCALE_WIDTH * SCALE_HEIGHT);
  memcpy(m_pic_in.img.plane[1],pictOut->data[1],SCALE_WIDTH * SCALE_HEIGHT/4);
  memcpy(m_pic_in.img.plane[2],pictOut->data[2],SCALE_WIDTH * SCALE_HEIGHT/4);
  m_pic_in.img.plane[3] = 0; 
  
  for(int iPlane = 0; iPlane < 3; iPlane++)
  {
   m_pic_in.img.i_stride[iPlane] = pictOut->linesize[iPlane];
  }
  m_pic_in.img.i_stride[3] = 0;
  
  int frame_size = x264_encoder_encode(m_pEncoder, &m_nals, &i_nals, &m_pic_in, &m_pic_out);
  

  Please help if possible, as this has been consuming a lot of time at my end. But I am not able to dig in to the library side for debugging. Any experienced hands are requested to assist.

• generate sdp file

  8 décembre 2011, par ДМИТРИЙ МАЛИКОВ

  How can it possible to generate *.sdp file for some video file using ffmpeg or cvlc from command line without playing video?

  I'm expecting something like

  ffmpeg --sdp-out="./file.sdp" ${videoFile}
  

  which produce file.sdp containing all necessary information.

• Getting PTS from MPEG-4 ?

  8 décembre 2011, par Javi

  I'm trying to get the PTS value from a MPEG-4 video that I'm streaming using RTP without using Transport Stream (TS). I've been able to get this value when muxing the video in TS, but now I want to send the video without using the TS and I wonder where to locate the PTS...

  Is there any header that indicates where the PTS is stored or something?

  Thanks for your help!