Recherche avancée

Sur d’autres sites (3187)

• ffmpeg does not fill in my provided buffer

  14 avril 2018, par thelearner

  I’m trying to pipe a mp4 video to ffmpeg to generate a thumbnail. Unfortunately, ffmpeg does not fill in my provided buffer, even though the whole command execution is successful.

  I’m reading the video from a http request body :

  videoData, err := ioutil.ReadAll(r.Body)

  This is how I push it to ffmpeg :

  log.Print("Creating thumbnail..")
  
  
  
  width := 640
  
  height := 360
  
  log.Print("Size of the video: ", len(videoData))
  
  
  
  
  
  cmd := exec.Command("ffmpeg", "-i", "pipe:0", "-vframes", "1", "-s", fmt.Sprintf("%dx%d", width, height), "-f",  "singlejpeg", "-frame_size", fmt.Sprintf("%d", totalVideoBytes), "-")
  
  
  
  cmd.Stdin = bytes.NewReader(videoData)
  
  
  
  var imageBuffer bytes.Buffer
  
  cmd.Stdout = &imageBuffer
  
  err := cmd.Run()
  
  
  
  if err != nil {
  
      log.Panic("ERROR")
  
  }
  
  
  
  imageBytes := imageBuffer.Bytes()

  This is the error output :

  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7ff05d002600]stream 0, offset 0x5ded : partial file

  pipe:0 : Invalid data found when processing input

  Finishing stream 0:0 without any data written to it.

  frame= 0 fps=0.0 q=0.0
  Lsize= 0kB time=-577014:32:22.77 bitrate= -0.0kbits/s speed=N/A
  video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
  muxing overhead : unknown

  Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)

  Thanks a lot, any help is appreciated.

• avformat_write_header() doesn't work when writing data to memory instead of file

  12 novembre 2020, par Mohamed Kandeel

  i want to resample a given input format from memory to memory everything is good so far.

  


  but when trying to get the output header from ffmpeg it doesn't work.

  


  here i allocate the context and pass the write_buffer function pointer so that it doesn't write to a file but instead it will call my function with the required data

  


  unsigned char * aviobuffer = (unsigned char *) av_malloc (32768);
AVIOContext * avio = avio_alloc_context (aviobuffer, 32768,1, NULL, NULL, write_buffer, NULL);

AVFormatContext* containerContext;
avformat_alloc_output_context2(&containerContext, NULL, "s16le", NULL);
containerContext->pb = avio;


  


  here is my write_buffer function

  


  std::vector<char>* data;&#xA;int write_buffer(void *opaque, uint8_t *buf, int buf_size)&#xA;{&#xA;    std::vector<char> tmp;&#xA;    tmp.assign(buf, buf &#x2B; buf_size);&#xA;    data->insert(data->end(), tmp.begin(), tmp.end());&#xA;    return buf_size;&#xA;}&#xA;</char></char>

  


  now when i call avformat_write_header() it doesn't call my write_buffer() function + it returns 0 which means success.

  


  int ret = avformat_write_header(containerContext, NULL);


  


  after that i call the appropriate functions to get the data body itself and my write_buffer() get called normally so i am now left with the data body with no header !!

  


  how can i get the output header anyways ?

  


• how to get cmsamplebuffer data to avformate_open_input() function in FFMpeg ?

  17 mai 2018, par Shahrear Mahmud

  i want to stream apple mobile camera to a UDP port using FFMPEG. so far i have already done it from a video file. but now i want to do it live from apple mobile camera.
  some body can give me some clue for this. my head is spining for this solution ?
  Please help me.