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• FFMpeg used in a C# MVC 3 app

  2 février 2012, par Chris

  I'm slowly going mad here and I'll apologise now as this question is going to be vague but I'm really struggling with getting video converting working reliably with FFMpeg. I've tried a few different wrappers but they all seem to go the same way.

  What I mean by that is unreliable converting (told you it would be vague), one time it will convert a video fine with no problems then the next it will just create a empty file. One solution I have tried is http://jasonjano.wordpress.com/2010/02/09/a-simple-c-wrapper-for-ffmpeg/ with unreliable results. I've currently even tried to get a trial version of a paid solution working (Media Handler by http://www.mediasoftpro.com/) with no joy either. I've worked on this for nearly the whole week and I've still go no closer to a reliable solution. Anyone with any help about anything really would be appreciated as I'm slowly going insane.

• using FFmpeg, how to decode H264 packets

  28 mars 2017, par Jun

  I’m new to FFmpeg struggling to decode H264 packets which can be obtained as an array of uint8_t.

  After many of investigations, I think it should be able to just put the array into an AVPacket like the below

  AVPacket *avpkt = (AVPacket *)malloc(sizeof(AVPacket) * 1);
  
  av_init_packet(avpkt);  
  
  avpkt->data = ct;   // ct is the array
  
  avpkt->length =....

  and decode by avcodec_decode_video2(). A part of the code is like

  ...
  
  codec = avcodec_find_decoder(CODEC_ID_H264);
  
  gVideoCodecCtx = avcodec_alloc_context();
  
  gFrame = avcodec_alloc_frame();
  
  avcodec_decode_video2(gVideoCodecCtx, gFrame, &frameFinished, packet);
  
  ...

  I guess I set all required properties properly but this function is returning only -1 :(

  I just found the -1 is coming from

  ret = avctx->codec->decode(avctx, picture, got_picture_ptr, avpkt) ;

  in the avcodec_decode_video2() ;

  Actually, what I’m wondering is if I can decode H264 packets (without RTP header) by avcodec_decode_video2().

  Thanks for the help in advance.

  ---

  /////////// added

  OK, I’m still trying to find a solution. What I’m doing now is the below

  ** the H264 stream in this RTP stream is encoded by FU-A

  1. receive a RTP packet

  2. look if the second byte of the RTP header is > 0 which means it’s the first packet (and possibly will be followed)

  3. see if the next RTP packet has > 0 at its second byte also, then it means the previous frame was a complete NAL or if this is < 0, the packet should be appended to the previous packet.

  4. remove all RTP header of the packets so it has only like FU indicator | FU header | NAL

  5. try play it with avcodec_decode_video2()

  but it’s only returning -1..... am I supposed to remove FU indicator and header too ??

  any suggestion will be very appreciated

  thanks in advance.

• Wav to Ogg or MP3 in PHP

  27 mai 2012, par Kamil Krzyszczuk

  Is there any solution for converting Wav to Ogg or MP3 by using pure PHP ?
  Technically it's possible. But what about ready-made libraries ?

  Im talking about 1-7 sec wav.