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• Access Violation at avcodec_encode_video2()

  23 mars 2016, par bot1131357

  I am trying to understand the FFmpeg API by following online examples available but it seems that the FFmpeg API has changed over time, making most of the examples obsolete ; I hope some of you can help me make more sense of the FFmpeg API examples.

  I am currently trying to understand the encoding-example from FFmpeg, but I am getting an Access Violation error at this line :

  out_size = avcodec_encode_video2(codecCtx, &avpkt, picture, &got_packet);

  where I get "Unhandled exception at 0x77c29e42 in test01_encode.exe : 0xC0000005 : Access violation reading location 0xccccccc8." from Visual Studio.

  I understand that avcodec_encode_video() is deprecated in favour of avcodec_encode_video2(), which uses AVPacket. I’ve allocated a buffer to data member of AVPacket and set its size, but still the same. What did I miss ?

  The library that I’m using is ffmpeg-20160219-git-98a0053-win32-dev. I would really really appreciate if you could help me out of this confusion.

  (Side : What does it mean by "get delayed frames" and why are we encoding by specifying AVFrame* parameter as NULL ?)

  /*
  
   * Video encoding example
  
   */
  
  char filename[] = "test.mpg";
  
  int main(int argc, char** argv)
  
  {
  
      AVCodec *codec;
  
      AVCodecContext *codecCtx= NULL;
  
      int i, out_size, size, x, y, outbuf_size;
  
      FILE *f;
  
      AVFrame *picture;
  
      uint8_t *outbuf, *picture_buf;
  
  
  
      printf("Video encoding\n");
  
  
  
      // Register all formats and codecs
  
      av_register_all();
  
  
  
      /* find the mpeg1 video encoder */
  
      codec = avcodec_find_encoder(AV_CODEC_ID_MPEG1VIDEO);
  
      if (!codec) {
  
          fprintf(stderr, "codec not found\n");
  
          exit(1);
  
      }
  
  
  
      codecCtx= avcodec_alloc_context3(codec);
  
      picture= av_frame_alloc();
  
  
  
      /* put sample parameters */
  
      codecCtx->bit_rate = 400000;
  
      /* resolution must be a multiple of two */
  
      codecCtx->width = 352;
  
      codecCtx->height = 288;
  
      /* frames per second */
  
      //codecCtx->time_base= (AVRational){1,25};
  
      codecCtx->time_base.num = 1;
  
      codecCtx->time_base.den = 25;
  
  
  
      codecCtx->gop_size = 10; /* emit one intra frame every ten frames */
  
      codecCtx->max_b_frames=1;
  
      codecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
  
  
  
      /* open it */
  
      if (avcodec_open2(codecCtx, codec, NULL) < 0) {
  
          fprintf(stderr, "could not open codec\n");
  
          exit(1);
  
      }
  
  
  
      fopen_s(&f,filename, "wb");
  
      if (!f) {
  
          fprintf(stderr, "could not open %s\n", filename);
  
          exit(1);
  
      }
  
  
  
      /* alloc image and output buffer */
  
      outbuf_size = 100000;
  
      outbuf = (uint8_t*) malloc(outbuf_size);
  
      size = codecCtx->width * codecCtx->height;
  
      picture_buf = (uint8_t*) malloc((size * 3) / 2); /* size for YUV 420 */
  
  
  
      picture->data[0] = picture_buf;
  
      picture->data[1] = picture->data[0] + size;
  
      picture->data[2] = picture->data[1] + size / 4;
  
      picture->linesize[0] = codecCtx->width;
  
      picture->linesize[1] = codecCtx->width / 2;
  
      picture->linesize[2] = codecCtx->width / 2;
  
  
  
      picture->width = codecCtx->width;
  
      picture->height = codecCtx->height;
  
      picture->format = codecCtx->pix_fmt;
  
  
  
      AVPacket avpkt;
  
      int got_packet;
  
  
  
      avpkt.size=av_image_get_buffer_size(codecCtx->pix_fmt, codecCtx->width,
  
                      codecCtx->height,1);    
  
      avpkt.data = (uint8_t *)av_malloc(avpkt.size*sizeof(uint8_t));
  
  
  
      /* encode 1 second of video */
  
      for(i=0;i<25;i++) {
  
          fflush(stdout);
  
          /* prepare a dummy image */
  
          /* Y */
  
          for(y=0;yheight;y++) {
  
              for(x=0;xwidth;x++) {
  
                  picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
  
              }
  
          }
  
  
  
          /* Cb and Cr */
  
          for(y=0;yheight/2;y++) {
  
              for(x=0;xwidth/2;x++) {
  
                  picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
  
                  picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
  
              }
  
          }
  
  
  
          /* encode the image */
  
          //out_size = avcodec_encode_video(codecCtx, outbuf, outbuf_size, picture);
  
          // <access violation="violation"> 
  
          out_size = avcodec_encode_video2(codecCtx, &amp;avpkt, picture, &amp;got_packet); 
  
          printf("encoding frame %3d (size=%5d)\n", i, out_size);
  
          //fwrite(outbuf, 1, out_size, f);
  
          fwrite(avpkt.data, 1, avpkt.size, f);
  
      }
  
  
  
      /* get the delayed frames */
  
      for(; out_size; i++) {
  
          fflush(stdout);
  
  
  
          //out_size = avcodec_encode_video(codecCtx, outbuf, outbuf_size, NULL);
  
          out_size = avcodec_encode_video2(codecCtx, &amp;avpkt, NULL, &amp;got_packet); 
  
          printf("write frame %3d (size=%5d)\n", i, out_size);
  
          //fwrite(outbuf, 1, out_size, f);
  
          fwrite(avpkt.data, 1, avpkt.size, f);
  
      }
  
  
  
      /* add sequence end code to have a real mpeg file */
  
      outbuf[0] = 0x00;
  
      outbuf[1] = 0x00;
  
      outbuf[2] = 0x01;
  
      outbuf[3] = 0xb7;
  
      fwrite(outbuf, 1, 4, f);
  
      fclose(f);
  
      free(picture_buf);
  
      free(outbuf);
  
  
  
      avcodec_close(codecCtx);
  
      av_free(codecCtx);
  
      av_free(picture);
  
      printf("\n");
  
  }
  
  </access>

• Files dissapearing with ffmpeg recursive conversion

  22 mai 2021, par CaRoXo

  I started in askubuntu, asking for a way to convert recursively more than 14K of wma to mp3 extracting the wma files path from a txt file.
There was an answer that could cover my needs, but a bug appears. The first run with some hundreds worked ok. The second, some wma albums got converted, others entirely deleted. There were some modifications. And last time completely, deleted all wma without converting.

  


  this was the original script

  


  #!/usr/bin/env bash

readarray -t files < wma-files.txt

for file in "${files[@]}"; do
    out=`echo $file | sed "s:wma:mp3:"`
    probe=`avprobe -show_streams "$file" 2>/dev/null`
    rate=`echo "$probe" | grep "bit_rate" | sed "s:.*=\(.*\)[0-9][0-9][0-9][.].*:\1:"`
    avconv -i "$file" -ab "$rate"k "$out"
    rm "$file"
done


  


  Then the adaptation with ffmpeg

  


  #!/usr/bin/env bash

readarray -t files < wma-files.txt

for file in "${files[@]}"; do
    out=`echo $file | sed "s:wma:mp3:"`
    probe=`avprobe -show_streams "$file" 2>/dev/null`
    rate=`echo "$probe" | grep "bit_rate" | sed "s:.*=\(.*\)[0-9][0-9][0-9][.].*:\1:"`
    ffmpeg -i "$file" -ab "$rate"k "$out" && rm "$file"
done


  


  With the first one I converted many files. Other just get deleted. The ones deleted were always the same release (so, all tracks from a release). I can listen, and even convert them with Soundkonverter.

  


  Both of them produces "no such file of directory" and when this happens, everything get deleted.

  


  The partition where files are stored is a usb HDD ntfs, but also happens in my ext4 internal HD.
I'm under Xubuntu 14.04

  


  Here the script running with avconv (which what I managed to convert some, but other get disappeared) http://pastebin.com/w5weqEws and with ffmpeg (that didn't convert any) http://pastebin.com/3QkaPzvW

  


  I can't find differences between successfully and deleted original wma's. But for example, while other progs like beets read and write the tags, puddletag and mp3tag (under wine) don't, until I converted them with soundkonverter.

  


  As the person trying to help me there redirect me here on the original post https://askubuntu.com/questions/508278/how-to-use-ffmpeg-to-convert-wma-to-mp3-recursively-importing-from-txt-file/508304#508304
I'm here asking for any help to make run an script like this. Or any to use ffmpeg to convert recursively the audio files. My capacity of understanding is short for being able to make something working just reading the docs.

  


  So I ask a help to run this. If I miss any relevant information, just tell me.

  


  NOTE : I want to add that doing the conversion with

  


  for file in "${files[@]}"; do
    out=`echo "$file" | sed s:wma:mp3:`
    avconv -i "$file" -ab 192k "$out"
    rm "$file"
done


  


  It works in the same files (the ones that are deleted with the other). Only that it makes everything to 192k, so not good if I'm converting lower bitrate ones. And get this error "Application provided invalid, non monotonically increasing dts to muxer in stream 0" that seems something typical from avconv in 14.04. With ffmpeg I cant try because I don't find the way how to use it, even out of the script. I really don't understand the docs seems
.

  


  NOTE2 : This is a mediainfo exit from :

  


  1- A typical wma that get disappeared always with the script

  


  Audio
ID                                       : 1
Format                                   : WMA
Format version                           : Version 2
Codec ID                                 : 161
Codec ID/Info                            : Windows Media Audio
Description of the codec                 : Windows Media Audio 9 - 128 kbps, 44 kHz, stereo 1-pass CBR
Duration                                 : 2mn 25s
Bit rate mode                            : Constant
Bit rate                                 : 128 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 44.1 KHz
Bit depth                                : 16 bits
Stream size                              : 2.21 MiB (99%)
Language                                 : English (US)


  


  2- A Wma that got successfully converted (yes I'm using copies now, I can't risk specially some rare audios that I got on the road)

  


  Audio
ID                                       : 1
Format                                   : WMA
Format version                           : Version 2
Codec ID                                 : 161
Codec ID/Info                            : Windows Media Audio
Description of the codec                 : Windows Media Audio 9 - 128 kbps, 44 kHz, stereo 1-pass CBR
Duration                                 : 4mn 35s
Bit rate mode                            : Constant
Bit rate                                 : 128 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 44.1 KHz
Bit depth                                : 16 bits
Stream size                              : 4.21 MiB (99%)
Language                                 : English (US)


  


  So, as I don't see difference, but maybe, I'm losing any data to look into ?

  


• How to copy a file open from open dialog to other location in vb.net

  4 juillet 2017, par Silvia Fonseca

  I have start a new application that converts video to image and then image to gif
  every thing is ok if i put my video in side of the same folder but if i not put my video in the same folder of the project the ffmpeg its says no such file or directory. wen i click to chose my file with openfiledialog , how can i copy or move my chose video to the correct directory in this case C :\avitogifconverter

  I have try to move the file to other location but wen i try to move the file to a different location its say i can not find the directory but the directory exist. what i have miss here this is the code

  This is my code

  Imports System.Diagnostics
  
  Imports System.ComponentModel
  
  Imports System
  
  Imports System.IO
  
  Imports System.IO.Compression
  
  Imports System.Windows.Forms
  
  Imports System.Net
  
  
  
  Public Class Form1
  
  Dim fpsx = 10
  
  Dim video = ""
  
  Dim startInfo As New ProcessStartInfo("ffmpeg.exe")
  
  Dim frame As Long 'individual frames
  
  Dim tempdir As String = "C:\avitogifconverter\" ' images temp directory
  
  Dim DestPath As String = "C:\avitogifconverter\"
  
  Public Declare Auto Function FindWindowNullClassName Lib "user32.dll" Alias "FindWindow" (ByVal lpClassname As Integer, ByVal lpWindownName As String) As Integer
  
  Dim Counter As Integer = 0
  
  
  
  Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
  
      My.Computer.FileSystem.CreateDirectory(tempdir)
  
      TextBox1.Text = "exp:-->video.avi or webm or flv"
  
      TextBox1.Clear()
  
      TextBox2.Text = fpsx
  
  
  
  
  
  End Sub
  
  
  
  
  
  Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
  
      fpsx = TextBox2.Text
  
      TextBox2.Text = fpsx
  
  
  
      Dim p As Process = Process.Start("cmd", "/k ffmpeg.exe -i " + TextBox1.Text + " -framerate 5/1 -filter:v fps=" + TextBox2.Text + " C:\avitogifconverter\out%02d.jpg")
  
      p.WaitForExit()
  
  
  
      If p.HasExited Then
  
          MsgBox("The Extraction Are Finish...")
  
      End If
  
  
  
  End Sub
  
  
  
  Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
  
  
  
  End Sub
  
  
  
  Private Sub Button2_Click(sender As Object, e As EventArgs)
  
  
  
  End Sub
  
  
  
  Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
  
  
  
  
  
      If (OpenFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK) Then
  
          'TextBox1.Text = OpenFileDialog1.FileName
  
          'TextBox1.Text = System.IO.Path.GetFileName(OpenFileDialog1.FileName)
  
          TextBox1.Text = System.IO.Path.GetDirectoryName(OpenFileDialog1.FileName)
  
          Dim newdialog As New OpenFileDialog()
  
          If newdialog.ShowDialog() = DialogResult.OK Then
  
              System.IO.File.Copy(newdialog.FileName, tempdir)
  
              MessageBox.Show(System.IO.Path.GetDirectoryName(newdialog.FileName) & "\" & System.IO.Path.GetFileName(newdialog.FileName))
  
          End If
  
      End If
  
      If TextBox1.Text = Nothing Then
  
          Return
  
      End If
  
      If TextBox1.Text <> Nothing Then
  
          'My.Computer.FileSystem.CopyFile(TextBox1.Text, DestPath)
  
      End If
  
  
  
  End Sub
  
  
  
  Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
  
      Dim args As String 'declare args
  
      args = " -i C:\avitogifconverter\out%02d.jpg -r 10 C:\avitogifconverter\out.gif "
  
      'args = " -i C:\avitogifconverter\out%02d.jpg -c:v libx264 -r 30 -pix_fmt yuv420p C:\avitogifconverter\out.mp4 "
  
      Dim proc As New Process
  
      Dim proci As New ProcessStartInfo
  
      proci.FileName = My.Application.Info.DirectoryPath & "\ffmpeg.exe"
  
      proci.Arguments = args
  
      proci.WindowStyle = ProcessWindowStyle.Hidden
  
      proci.CreateNoWindow = True
  
      proci.UseShellExecute = False
  
      proc.StartInfo = proci
  
      proc.Start()
  
      Do Until proc.HasExited = True
  
          Me.Text = "Saving"
  
      Loop
  
      Me.Text = "your video done"
  
  
  
      MsgBox("Done")
  
      Dim directoryName As String = "C:\avitogifconverter\"
  
      For Each deleteFile In Directory.GetFiles(directoryName, "*.jpg", SearchOption.TopDirectoryOnly)
  
          File.Delete(deleteFile)
  
      Next
  
  
  
      'IO.Directory.Delete(tempdir, True)
  
  End Sub
  
  
  
  Private Sub Button5_Click(sender As Object, e As EventArgs) Handles Button5.Click
  
      Form2.Show()
  
  
  
  End Sub
  
  End Class