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• FFmpeg Centos Compile Error - caused by libwebp (error: implicit declaration of function ‘libwebp_error_to_averror’)

  2 September 2022, by fvid1

  I'm trying to compile FFmpeg on Centos 7.9. I followed the official instructions: https://trac.ffmpeg.org/wiki/CompilationGuide/Centos

  


  I need support for WebP images, so I installed libwebp and libwebp-devel via YUM, and used the option --enable-libwebp.

  


  But at the ffmepg "make" stage, the following error is returned:

  


  CC      libavcodec/libwebpenc_common.o
libavcodec/libwebpenc_common.c: In function ‘ff_libwebp_get_frame’:
libavcodec/libwebpenc_common.c:283:17: error: implicit declaration of function ‘libwebp_error_to_averror’ [-Werror=implicit-function-declaration]
                 ret = libwebp_error_to_averror(pic->error_code);
                 ^
cc1: some warnings being treated as errors
make: *** [libavcodec/libwebpenc_common.o] Error 1


  


  Does anyone know why this error is occuring and how it can be corrected?

  


  I've tried compiling without using --enable-libwebp and it works fine.

  


• Continuous RTMP Streaming with FFmpeg Without Restarting the Process for New Videos

  3 April 2024, by 刘小佳

  I'm facing a challenge with my workflow and would appreciate any guidance or solutions you might have. My business scenario involves a service that periodically generates new video files locally (e.g., 1.mp4, 2.mp4, ...). These files are then streamed to an RTMP server using FFmpeg, and clients pull the stream via HTTP-FLV for playback.

  


  My goal is to ensure continuous streaming between video files without restarting the FFmpeg process each time a new video is ready to be streamed. Restarting FFmpeg for each new file introduces a disconnect in the client playback, which I'm trying to avoid to maintain stream continuity.

  


  I've explored several approaches based on the FFmpeg Concatenate wiki (https://trac.ffmpeg.org/wiki/Concatenate), but haven't achieved the desired outcome:
  
Approach 1:
  
Using a list.txt file with ffconcat version 1.0 and dynamically updating the file (next.mp4) being played:

  


  ffconcat version 1.0
file next.mp4
file next.mp4


  


  And then streaming with:
ffmpeg -re -stream_loop -1 -f concat -i list.txt -flush_packets 0 -f flv rtmp://xxx
  
However, when attempting to replace next.mp4 (e.g., moving 2.mp4 to next.mp4 during the streaming of 1.mp4), I encountered a "device busy" error.
  
Approach 2:
  
Using a nested list approach where list1.txt includes 1.mp4 and list2.txt, and vice versa:

  


  // list1.txt
ffconcat version 1.0
file '1.mp4'
file 'list2.txt'
// list2.txt
ffconcat version 1.0
file '2.mp4'
file 'list1.txt'


  


  Streaming with: ffmpeg -re -stream_loop -1 -f concat -i list1.txt -flush_packets 0 -f flv rtmp://xxx
  
In this setup, I tried modifying list1.txt to replace 1.mp4 with 3.mp4 during the streaming of 2.mp4, but FFmpeg would loop back to 1.mp4 and 2.mp4 before streaming 3.mp4 in the next cycle.

  


  Am I missing something in my methods? Does anyone have a better approach to fulfill this requirement? Any help would be greatly appreciated!

  


• Adding HEVC reference decoder to ffmpeg framework

  4 March 2014, by 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.