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• Anomalie #4402 (Fermé) : Liste de notices

  12 février 2021, par cedric -

  je ferme ce ticket, car un ticket qui référence un wiki qui liste des patches, ça commence à ressembler à un jeu de pistes
  + depuis novembre 2019 ces notices ont été corrigée
  + maintenant proposer une PR pour chaque cas quand on tombe dessus ça sera beaucoup plus efficace

• Broadcast Screen using ffmpeg to encode H.264

  29 avril 2018, par Erick Weil

  Background History :

  So. doing a program, I need a way to broadcast my desktop screen, trought local network( maybe wi-fi ), to aproximately 40 clients, primarily in windows, but if it also works in linux, will be great.

  Started doing my own video compression protocol, in Java, taking the hilbert curve as a inspiration ( it transmit 10 fps, 1024x720, horrible 8-bit colors, using 5 MB of bandwith) but the color quality was very low, and fps wasn’t that good, cpu usage blowing up to 50%, memory 800M. 

  So i realized i’ll never be able to do a proper encoding algorithm and tried to use ffmpeg to encode the screenshots in a video and transmit this.

  I tried :

  • Xuggler : not supported anymore, examples worked, but it does lack tutorials and things that explain how it works
  • VLCJ : VLC wraper for java, requires the client of the transmission to have VLC installed.
  • JavaCV : java wrapper of openCV, to wrap ffmpeg. my program size blows up if i include this
  • FFMPEG : in c++ i created a project, communication with java trought JNI, the remuxing example worked,
    but i don’t now how to use it to do what I want

  The actual question :

  How can i make a c++ program able to encode image frames into a H264 stream and send it trought UDP ?

  i mean, is there any tutorial on ffmpeg, any place to start learning how to use it.

• Error while decoding Raw H264 frames using ffmpeg

  25 avril 2020, par raullalves

  I would really appreciate some help in this issue. I'm new to FFmpeg, therefore forgive me if this is a dumb question

  



  I have an application streamming H264 raw data from a camera via UDP. That communication works fine. The problem is while trying to decoding

  



  I simply want to decode that data I receive, in order to apply a few Computer Vision techniques to another project.

  



  I got error -22 right after calling

  



  avcodec_send_packet


  



  Does any of you know what could it be ? Here is part of my code

  



  Mat DecodificadorH264::h264decode(char* rawH264, int size){
 ...
 ...
AVPacket av_packet;
av_init_packet(&av_packet);
uint8_t data;
data = *rawH264;
av_packet.data = &data;
av_packet.size = size;

cout << "size = "< avcodec_find_decoder(AV_CODEC_ID_H264);

l_pAVCodecContext = avcodec_alloc_context3(l_pCodec);

l_pAVCodecContext->width = FRAME_WIDTH;
l_pAVCodecContext->height = FRAME_HEIGHT;
l_pAVCodecContext->extradata = NULL;

l_pAVCodecContext->pix_fmt = AV_PIX_FMT_YUV420P;

int av_return = avcodec_send_packet(l_pAVCodecContext,
(AVPacket*)&av_packet);
if (av_return == AVERROR(EINVAL))cout << "codec not opened, or it is an encoder" << endl;
 ....


  



  av_return returns "AVERROR(EINVAL)", which is defined as -22

  



  What could be the problem ?

  



  Thanks in advance !