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• transcoding legacy MJPEG camera stream using ffmpeg to rstp stream

  1er décembre 2013, par Arcko

  I am trying out this solution to transcoding legacy MJPEG camera stream using ffmpeg to rstp stream, which originally posted on http://www.wowza.com/forums/showthread.php?11218-Transcoding-Solution-For-Legacy-MJPEG-Cameras

  As the post is a little old, so it seems not working well in ubuntu 12.04 with the latest ffmpeg source code from git ://source.ffmpeg.org/ffmpeg.git

  Here's the steps :

  1. Compile and installed ffmpeg follwing guide https://trac.ffmpeg.org/wiki/UbuntuCompilationGuide

  2. Created ffserver.conf and running ffserver successfully using server.sh

      !/bin/bash

     while [ 1 ]
     do
     ffserver -loglevel verbose
     done

  3. created pull_stream_http.php following the guide

  4. Created stream.sh and running :

      !/bin/bash

     while [ 1 ]
     do

     php -f pull_stream_http.php | ffmpeg -an -f mjpeg -maxrate 500 -b24k -r 6 -i - 6 http://[serverip]:8090/feed1.ffm

     php -f pull_stream_http.php | ffmpeg -an -f mjpeg -r -i -vcodec libx264 -map 0 -vpre fastfirstpass -vpre baseline -b 24k -bt 32k -threads 0 http://[serverip]:8090/feed1.ffm

     done

  Now comes the error with stream.sh : "Invalid input file index : 0".

  Any one who familiar with ffmpeg would give some advice ?

  Thanks,
  Arcko

• FFMPEG : Is defining a context for a codec compulsary ?

  28 novembre 2013, par sam

  I'm having a a decoder code. I'm trying to integrate it into ffmpeg framework.

  I'm referring to the HOW TO given here : http://wiki.multimedia.cx/index.php?title=FFmpeg_codec_howto

  According to that article i need to define a structure in my decoder_name.c file.

  The example structure is shown below :

  AVCodec sample_decoder =
  
  {
  
      .name           = "sample",
  
      .type           = AVCODEC_TYPE_VIDEO,
  
      .id             = AVCODEC_ID_SAMPLE,
  
     // .priv_data_size = sizeof(COOKContext),
  
      .init           = sample_decode_init,
  
      .close          = sample_decode_close,
  
      .decode         = sample_decode_frame,
  
  };

  Where,

  .name -> specifies the short name of my decoder.
  
  
  
  .type -> is used to specify that it is a video decoder.
  
  
  
  .id -> is an unique id that i'm assigning to my video decoder.
  
  
  
  .init -> is a function pointer to the function in my decoder code that performs decoder related initializations
  
  
  
  .decode -> is a function pointer to the function in my decoder code that decodes a single frame, given the input data (elementary stream).
  
  
  
  .close -> is a function pointer to the function in my decoder that frees all allocated memory i.e. the memory allocated in init.

  However, my doubt is according to the above mentioned article, there is another field called .priv_data_size which hold the size of some context.

  Is it compulsory to have this field .priv_data_size because according to the above article, i need not define all the parameters of the structure AVCodec. Further i do not possess any such context for my decoder.

  However, when i go through the code of other available decoders in libavcodec of ffmpeg, i find that every decoder has defined this. Will my decoder work if i do not specify this ? I'm unable to proceed because of this. please provide some guidance regrading the same.

  —Thanks in advance.

• Adding HEVC reference decoder to ffmpeg framework

  4 mars 2014, par Zax

  I have a tweaked HM reference code of HEVC Decoder based on my requirements. I also know that FFMPEG version 2.1 onwards supports HEVC. But its a necessity for me to integrate my modified HM code.

  Hence I have gone through the post :

  http://wiki.multimedia.cx/index.php?title=FFmpeg_codec_howto

  According to this post, I need to define some functions that are needed to add a new decoder support to FFMPEG framework.

  The structure is : typedef struct AVCodec

  I have defined a structure as shown below :

  AVCodec HMHEVC_decoder =
  
  {
  
      .name           = "hmhevc",
  
      .type           = AVMEDIA_TYPE_VIDEO,
  
      .id             = AV_CODEC_ID_HMHEVC,
  
  
  
      .init           = hmhevc_decode_init,
  
      .close          = hmhevc_decode_close,
  
      .decode         = hmhevc_decode_frame,
  
  };

  However, looking at the other examples, I feel I have to add another variable like :

      .priv_data_size = sizeof(HEVCContext),

  But the problem is that I don't have any such context. So in case I don't define this, what are the things that FFMPEG framework wont provide my decoder ?

  Also is definition of this private data context compulsary ?

  What are the other fields that have to be compulsorily defined ?

  My main intention is that FFPLAY should be able to play the decoded frame.