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• MPEG-TS Segments HTTP Live Streaming

  5 juin 2013, par user1069624

  I'm trying to interleave MPEG-TS segments but failing. One set of segments was actually captured using the built in camera in the laptop, then encoded using FFMPEG with the following command :

  ffmpeg -er 4 -y -f video4linux2 -s 640x480 -r 30 -i %s -isync -f mpegts -acodec libmp3lame -ar 48000 -ab 64k -s 640x480 -vcodec libx264 -fflags +genpts -b 386k -coder 0 -me_range 16 -keyint_min 25 -i_qfactor 0.71 -bt 386k -maxrate 386k -bufsize 386k -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -aspect 640:480

  And the other one is an avi file that was encoded using the following command :

  fmpeg -er 4 -y -f avi -s 640x480 -r 30 -i ./DSCF2021.AVI -vbsf dump_extra -f mpegts -acodec libmp3lame -ar 48000 -ab 64k -s 640x480 -vcodec libx264 -fflags +genpts -b 386k -coder 0 -me_range 16 -keyint_min 25 -i_qfactor 0.71 -bt 386k -maxrate 386k -bufsize 386k -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -aspect 640:480

  Then the output is segmented into ts segments using an open source segmenter.

  If both come from the same source (both from the camera) they work fine. However in this case, the second set of segments freeze. Time passes, but the video does not move..
  So i think it's an encoding problem. So my question is, how should i change the ffmpeg command for this to work ?

  By interleave I mean, having a playlist with the first set of segments, and another playlist with the other set of segments, and having the client call one then the other (HTTP Live Streaming)

  The ffprobe output of one of the first set of segments :

  Input #0, mpegts, from 'live1.ts':
  
    Duration: 00:00:09.76, start: 1.400000, bitrate: 281 kb/s
  
    Program 1 Service01
  
      Metadata:
  
        name            : Service01
  
        provider_name   : FFmpeg
  
      Stream #0.0[0x100]: Video: h264, yuv420p, 640x480 [PAR 1:1 DAR 4:3], 29.92 fps, 29.92 tbr, 90k tbn, 59.83 tbc
  
      Stream #0.1[0x101]: Audio: aac, 48000 Hz, stereo, s16, 111 kb/s

  The ffprobe output of one of the second set of segments :

  Input #0, mpegts, from 'ad1.ts':
  
    Duration: 00:00:09.64, start: 1.400000, bitrate: 578 kb/s
  
    Program 1 Service01
  
      Metadata:
  
        name            : Service01
  
        provider_name   : FFmpeg
  
      Stream #0.0[0x100]: Video: h264, yuv420p, 640x480 [PAR 1:1 DAR 4:3], 25 fps, 25 tbr, 90k tbn, 50 tbc
  
      Stream #0.1[0x101]: Audio: aac, 48000 Hz, stereo, s16, 22 kb/s

  Thank you,

• Programming in C : Opening, Reading and Transcoding of Live TV with libavcodec. libavformat etc

  19 décembre 2011, par mmoment

  I'm currently developing a live streaming Software for my University Project.

  I am supposed to open a Live Video Stream from a USB Stick( I am using the Hauppauge WinTV-HVR 950Q under Linux) and read the Stream.
  Then I'm supposed to transcode it to h246. and send it to some devices in the Network.

  My Problem

  ---

  I can use the v4l API to access the USB Stick, but transcoding does currently not work as far as I know, therefore I want to use the libav to do so. I know that using the command line tools transcoding of live streams with ffmpeg is not a big deal, but doing so in C seems to be more of a problem.

  1. Here's how I open some static Video File :

     static char* path = "./video.mpeg" ;
     AVFormatContext *pFormatCtx ;

     av_register_all() ;

     if(av_open_input_file(&pFormatCtx, path, NULL, 0, NULL) !=0)
     
     printf("Opening file \"%s\" failed", path) ;
     return -1 ;
     else printf("Opening the file \"%s\" succeeded", path) ;

  2. Here's how I understand to how open a Live Feed

     static char* path = "/dev/dvb/adapter0/dvr0" ;
     AVFormatContext *pFormatCtx ;

     av_register_all() ;
     avdevice_register_all() ;

     if(avformat_open_input(&pFormatCtx, path, NULL, NULL) != 0)
     
     perror("avformat_open_input") ;
     return -1 ;
     else printf("Yay") ;

  3. Here's how I understand to how open a Live Feed

     if(av_find_stream_info(pFormatCtx)<0)
     
     printf("Could not find any Stream Information the file \"%s\"", path) ;
     return -1 ;
     
     // Dump information about file onto standard error
     dump_format(pFormatCtx, 0, path, 0) ;
     AVCodecContext *pCodecCtx ;

     // Find the first video stream
     int videoStream=-1 ;
     for(i=0 ; inb_streams ; i++)
     

     if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO)
     
     {
     
         videoStream=i;
     
         break;
     
     }

     if(videoStream==-1) return -1 ; // Didn't find a video stream

     // Get a pointer to the codec context for the video stream
     pCodecCtx=pFormatCtx->streams[videoStream]->codec ;

     AVCodec *pCodec ;

     // Find the decoder for the video stream
     pCodec=avcodec_find_decoder(pCodecCtx->codec_id) ;
     if(pCodec==NULL)
     
     fprintf(stderr, "Unsupported codec !\n") ;
     return -1 ; // Codec not found
     
     //Open codec
     if(avcodec_open(pCodecCtx, pCodec)<0)
     
     printf("Could not open the Codec") ;
     return -1 ; // Could not open codec
     

  So now how can you help me ?

  I would really appreciate it if anyone knew how to open a live stream and could give me a good example.

• Streaming jpegs live to iphone app

  14 février 2012, par Raven

  Im progressing through taking the depth camera feed from my kinect and streaming it to my iphone app. I have got to stage of being able save jpegs for every frame created from the kinect depth image (30 fps) and save them to the local disk. I have than been able to convert this to mpeg with ffmpeg.

  My question is now how can I view this live on my iphone ? Basically I want to view it live on the iphone as you are seeing it coming from the kinect.

  Should I use http live streaming and use the segmenter to use apples HttpLiveStreaming functionality ? Or can I stream the raw jpeg image files up in some way as they are saved to disk and than just cycle the images on the phone as they go ?

  Im wondering how video conferencing is achieved on the iphone (facetime/skype etc) ? because I'd prefer that it wasnt played inside the video player, just want to display live content on the screen as it happens.

  Any ideas ? Thanks in advance