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• How to use Filter Graph to change format of image

  14 juillet 2016, par user6589949

  I am trying to take TS packets and create bitmaps that are displayed in a window. I am using a filter graph. I have the following filters in the graph.

  buffer -> yadif-> format-> buffersink

  If I leave the format filter out and use the code below, the image looks fine.

  AVFrame* frameRGBA = av_frame_alloc ( );
  
  frameRGBA->format = m_pCodecCtx->pix_fmt;
  
  frameRGBA->width = m_pCodecParameters->width;
  
  frameRGBA->height = m_pCodecParameters->height;
  
  int numBytes = avpicture_get_size ( AV_PIX_FMT_RGB24, m_pCodecParameters->width, m_pCodecParameters->height );
  
  uint8_t* frameRGBBuffer = (uint8_t *)av_malloc ( numBytes*sizeof(uint8_t) );
  
  
  
  av_image_fill_arrays ( frameRGBA->data, frameRGBA->linesize, frameRGBBuffer, AV_PIX_FMT_RGB24, m_pCodecParameters->width, m_pCodecParameters->height, 1 );
  
  
  
  static struct SwsContext *img_convert_ctx;
  
  img_convert_ctx = sws_getContext ( m_pCodecParameters->width, m_pCodecParameters->height, m_pCodecCtx->pix_fmt, m_pCodecParameters->width, m_pCodecParameters->height, AV_PIX_FMT_BGR24, SWS_ACCURATE_RND | SWS_ERROR_DIFFUSION | SWS_BICUBLIN, NULL, NULL, NULL );
  
  
  
  int iSWSValue = sws_scale ( img_convert_ctx, pAVFrame->data, pAVFrame->linesize, 0, m_pCodecParameters->height, frameRGBA->data, frameRGBA->linesize );
  
  
  
  If I use the format filter 
  
  AVFilter *aformat = avfilter_get_by_name ( "format" );
  
  
  
  err = avfilter_graph_create_filter ( &m_format_ctx, aformat, "format", "pix_fmts=3", NULL, m_filter_graph );

  I get a image that looks like the old TV image where the VSYNC is out. I attached the image. It should be a color bar test image.

  Any help is appreciated. Thanks.
  Distorted image

• Adobe connect video : FLV to MP4 (export, convert)

  4 mai 2022, par Guillaume Chevalier

  I would like to convert an adobe connect video from .flv in the downloaded zip to .mp4. I have already done the steps explained in this question and answer, however I get .flv files organised like this inside the .zip :

  



  

  



  Moreover, I know that ffmpeg can merge video and sound files together as well as concatenating resulting clips directly from the command-line which could be quite useful : https://www.labnol.org/internet/useful-ffmpeg-commands/28490/

  



  I can't ask the owner of the video to make it available as an .mp4 from within the adobe connect admin interface. Briefly, I would like to listen to those videos in x2 speed in VLC (just like what I do when listening to random math classes on YouTube - I put ON the x2 speed). The amount of time I would gain to watch adobe connect videos in x2 speed is MASSIVE.

  



  I think I am not the only one that would like to do this. There are a lot of questions on forums about downloading adobe connect videos, but the .flv format mixed with some .xml is generally a killer when the host does not make the videos properly available in .mp4.

  



  Dealing with the order of the .flv files is a puzzle. At least, I would not care to flush the chat away and leave some details like that behind, that would help to reconstruct the videos. Any scripts to automate the process would be useful.

  


• Flutter FFmpeg moov atom not found whilst running ffmpeg command during recording

  28 janvier 2021, par GILO

  Hi am currently trying to retrieve 3 second clips of an audio file whilst it is recording in flutter. I am using the recording module flutter sound and flutter ffmpeg.

  


  I record the audio file with default codec (.aac). The file is saved to the cache getTemporaryDirectory()

  


  I then copy the file using this flutter ffmpeg code

  


  List<string> arguments = ["-ss", start.toString(), "-i", inPath, "-to", end.toString(), "-c", "copy", outPath];&#xA;&#xA;await flutterFFmpeg.executeWithArguments(arguments);&#xA;</string>

  


  


  Start : start time (e.g. 0) and End : end time (e.g. 3)

  


  


  It then returns this error

  


  


  FFmpeg exited with rc : 1 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x748964ea00] moov
atom not found

  


  


  Helpful information :

  


  

  1. A moov atom is data about the file (e.g timescale,duration)

  


  2. I know the inPath exists because I check that before executing ffmpeg command

  


  3. The outPath is also format .aac

  


  4. This ffmpeg function is being ran whilst the recording is still occurring

  


  5. Example inPath uri looks like this /data/user/0/com.my.app/cache/output.aac

  


  6. I have no problems when running on iOS, only on android

  


  


  I would be grateful for help, I have spent many days trying to fix this problem. If you need anymore info please leave a comment. Thanks