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• ffmpeg can't read png data on iphone

  10 octobre 2014, par user2789801

  I’m using ffmpeg to decode a png picture and use the AVFrame as a opengl texture.
  But the strangest thing is that I can get the png converted to opengl texture nicely on a iphone simulator, but I got a blank texture on a real iphone.

  on both simulator and iphone, I got a null pointer for AVFrame’s data

  avcodec_decode_video2(codecContext/* AVCodecContext* */,frame /* AVFrame */,&finished,&tempPacket); 

  Then I covert the color space to AV_PIX_FMT_RGBA

  void convertToRGBColor()
  
  {
  
      int numBytes = avpicture_get_size(
  
                                    AV_PIX_FMT_RGBA,
  
                                    codecContext->width,
  
                                    codecContext->height);
  
      uint8_t *buffer = (uint8_t *)av_malloc(numBytes);
  
      avpicture_fill(rgbFrame/* AVFrame* */, buffer, AV_PIX_FMT_RGBA, codecContext->width, codecContext->height);
  
  
  
      struct SwsContext *img_convert_ctx = NULL;
  
      img_convert_ctx = sws_getCachedContext(
  
                           img_convert_ctx,
  
                           codecContext->width,
  
                           codecContext->height,
  
                           codecContext->pix_fmt,
  
                           codecContext->width,
  
                           codecContext->height,
  
                           COLOR_SPACE,
  
                           SWS_BILINEAR,
  
                           NULL,
  
                           NULL,
  
                           NULL);
  
  
  
      if( !img_convert_ctx )
  
      {
  
          fprintf(stderr, "Cannot initialize sws conversion context\n");
  
      }
  
  
  
      sws_scale(img_convert_ctx,
  
                frame->data,
  
                frame->linesize,
  
                0,
  
                codecContext->height,
  
                rgbFrame->data,
  
                rgbFrame->linesize);
  
      sws_freeContext(img_convert_ctx);
  
  }

  On a simulator, rgbFrame’s data[0] will be a valid pointer, but on a iphone, it’s null.

  So, does anyone had the same problem before ?

• I use ffmpeg dinamically to edit a local hosted video to be streamed on iPhone over 3G [on hold]

  3 octobre 2014, par Luchian Chivoiu

  I use ffmpeg dinamically to edit a local hosted video to be streamed on iPhone over 3G .

  I use this line :
  "ffmpeg -i C :\file1.mp4 -s 640x480 -r 30000/1001 -b:a 56k -bt 40k -b:v 50k -maxrate 10M -bufsize 10M -coder 0 -bf 0 -refs 1 -ar 48000 -ab 52k C :\file2.mp4" and it doesn’t work to open on iPhone the transformed file called "file2.mp4".
  I use Web Api and C# to call the ffmpeg locally and the resulted file opens on the browser but still doesn’t want to stream to an iPhone over 3G only if it’s over WiFi.

  Here Apple explains the process but I still didn’t get it work .

  https://developer.apple.com/library/safari/documentation/AppleApplications/Reference/SafariWebContent/CreatingVideoforSafarioniPhone/CreatingVideoforSafarioniPhone.html

  One example that can’t be played on IPhone is this one : http://www.starlety.com/Videos/8ada5277-424a-e411-b2e5-00ff91d7f3dd.mp4

• Live Stream using .m3u8 and .ts files with iPhone as server

  26 février 2015, par Bhumit

  I am trying to accomplish a task to live stream from iPhone camera. I have done some research and found that i can use .m3u8 files for streaming live video with should contain .ts(Mpeg-2) files .

  Now the file which i have on my iPhone is .mp4 file and it does not work with .m3u8, so i figured out i will have to convert .mp4 to .ts for that , but i have not succeeded in doing so.

  I found that it is possible to convert video ffmpeg lib as mentioned in this article here. I have successfully imported ffmpeg library but not able figure out how can i use it to convert a video as i am using this for first time.

  One another thing apple documentation says

  There are a number of hardware and software encoders that can create
  MPEG-2 transport streams carrying MPEG-4 video and AAC audio in real
  time.

  What is being said here ? is there any other way i can use .mp4 files for live streaming without converting them from iOS ?

  Let me know if i am not clear, i can provide more information .Any suggestion is appreciated. I would like to know am i on a right path here ?

  EDIT

  I am adding more info to my question, so basically what i am asking is , we can convert .mp4 video to .ts using following command

  ffmpeg -i file.mp4 -acodec libfaac -vcodec libx264 -an -map 0 -f segment -segment_time 10 -segment_list test.m3u8 -segment_format mpegts -vbsf h264_mp4toannexb -flags -global_header stream%05d.ts

  How can i use ffmpeg library to do what this command does in iOS.