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• ffmpeg - Understand images to video output, players show different images and lengths

  8 juillet 2023, par Matt C

  I'm using multiple images to create a video with each image on a 1-second long frame. This is the command I'm using :

  


   ffmpeg -framerate 1 -i 'image%d.jpg' -c:v libx264 -r 1 -pix_fmt yuv420p out.mp4


  


  This seems straightforward and exactly what many others have done with success. However, the output I get is an mp4 which windows file explorer says is 4 seconds long, and is different in VLC and Windows media player and neither is the desired output.

  


  In Windows : the video plays for 4 seconds with a black screen and at this point the time line at the bottom is filled up at 4 seconds, indicating the video is over. But it keeps playing, for another 4 seconds. And the last 4 seconds (from 0:04 to 0:07) is actually the desired output.

  


  





  


  


  


  


  



  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  Frame	Image
  1	black screen
  2	black screen
  3	black screen
  4	black screen
  5	image1.jpg
  6	image2.jpg
  7	image3.jpg
  8	image4.jpg

  


  


  In VLC : the video shows last image supplied as input for 3 seconds, followed by the second to last image for 1 second.

  


  





  


  


  


  


  



  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  Frame	Image
  1	image4.jpg
  2	image4.jpg
  3	image4.jpg
  4	image3.jpg

  


  


  Questions :

  


  

  1. How/Why are these different in different players ?

  


  2. Why, in VLC, are only two images showing up, and why would one of them last for 3 seconds ?

  


  3. In Windows, why/how is the video 8 seconds long but shows up as 4 seconds both in the file explorer and in the actual media player ?

  


  4. How do I get the desired output, and what caused my case to not work as it did for seemingly most others ?

  


  


• Demuxing a video media file with FFMPEG

  23 février 2016, par MOHW

  After starting this question Extracting the h264 part of a video file (demuxing) I was actually able to figure out that,

  1. When I reverted to an older version of FFMPEG (avcodec-55.dll) as against the avcodec-57.dll I was using earlier, the code worked perfectly without any error and the resultant h264 file played with ffplay.
  2. When I tracked my output when using the avcodec-57.dll version of FFMPEG (most recent version), there was actually an error "Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead" after the call avformat_write_header(ofmt_ctx_v, NULL) and another one after the call to avformat_write_header(ofmt_ctx_a, NULL). The program continued executing, the audio was fine but the .h264 file wasn’t.

  The output

  Press any key to continue . . .
  
  Press any key to continue . . .
  
  Press any key to continue . . .
  
  Press any key to continue . . .
  
  
  
  ==============Input Video=============
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'sample.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      title           : 10153755968775490
  
      encoder         : Lavf57.19.100
  
    Duration: 00:01:07.27, start: 0.020021, bitrate: 1058 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 400x224 [
  
  SAR 199:200 DAR 199:112], 927 kb/s, 15 fps, 15 tbr, 15360 tbn, 30 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo, s16p, 12
  
  8 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  
  
  ==============Output Video============
  
  Output #0, h264, to 'sample.h264':
  
      Stream #0:0: Video: h264 (High), yuv420p, 400x224 [SAR 199:200 DAR 199:112],
  
   q=2-31, 927 kb/s, 30 tbc
  
  
  
  ==============Output Audio============
  
  Output #0, mp3, to 'sample.mp3':
  
      Stream #0:0: Audio: mp3, 48000 Hz, stereo, s16p, 128 kb/s
  
  
  
  ======================================
  
  [h264 @ 00a3ee20] Using AVStream.codec.time_base as a timebase hint to the muxer
  
   is deprecated. Set AVStream.time_base instead.
  
  [mp3 @ 00a4fec0] Using AVStream.codec.time_base as a timebase hint to the muxer
  
  is deprecated. Set AVStream.time_base instead.
  
  Press any key to continue . . .

  The code

  #include 
  
  
  
  #define __STDC_CONSTANT_MACROS
  
  
  
  extern "C"
  
  {
  
      #include "libavformat/avformat.h"
  
  }
  
  
  
  
  
  #define USE_H264BSF 1
  
  
  
  int main()
  
  {
  
      AVOutputFormat *ofmt_a = NULL,*ofmt_v = NULL;
  
      AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx_a = NULL, *ofmt_ctx_v = NULL;
  
      AVPacket pkt;
  
      int ret, i;
  
      int videoindex=-1,audioindex=-1;
  
      int frame_index=0;
  
  
  
      const char *in_filename  = "sample.mp4";
  
      const char *out_filename_v = "sample.h264";
  
      const char *out_filename_a = "sample.mp3";
  
  
  
      av_register_all();
  
      //Input
  
      if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
  
          printf( "Could not open input file.");
  
          goto end;
  
      }
  
      if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
  
          printf( "Failed to retrieve input stream information");
  
          goto end;
  
      }
  
  system("pause");
  
  
  
      //Output
  
      avformat_alloc_output_context2(&ofmt_ctx_v, NULL, NULL, out_filename_v);
  
      if (!ofmt_ctx_v) {
  
          printf( "Could not create output context\n");
  
          ret = AVERROR_UNKNOWN;
  
          goto end;
  
      }
  
      ofmt_v = ofmt_ctx_v->oformat;
  
  
  
  system("pause");
  
  
  
      avformat_alloc_output_context2(&ofmt_ctx_a, NULL, NULL, out_filename_a);
  
      if (!ofmt_ctx_a) {
  
          printf( "Could not create output context\n");
  
          ret = AVERROR_UNKNOWN;
  
          goto end;
  
      }
  
      ofmt_a = ofmt_ctx_a->oformat;
  
  system("pause");
  
      for (i = 0; i < ifmt_ctx->nb_streams; i++) {
  
              //Create output AVStream according to input AVStream
  
              AVFormatContext *ofmt_ctx;
  
              AVStream *in_stream = ifmt_ctx->streams[i];
  
              AVStream *out_stream = NULL;
  
  
  
              if(ifmt_ctx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO){
  
                  videoindex=i;
  
                  out_stream=avformat_new_stream(ofmt_ctx_v, in_stream->codec->codec);
  
                  ofmt_ctx=ofmt_ctx_v;
  
              }else if(ifmt_ctx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO){
  
                  audioindex=i;
  
                  out_stream=avformat_new_stream(ofmt_ctx_a, in_stream->codec->codec);
  
                  ofmt_ctx=ofmt_ctx_a;
  
              }else{
  
                  break;
  
              }
  
  
  
              if (!out_stream) {
  
                  printf( "Failed allocating output stream\n");
  
                  ret = AVERROR_UNKNOWN;
  
                  goto end;
  
              }
  
              //Copy the settings of AVCodecContext
  
              if (avcodec_copy_context(out_stream->codec, in_stream->codec) < 0) {
  
                  printf( "Failed to copy context from input to output stream codec context\n");
  
                  goto end;
  
              }
  
              out_stream->codec->codec_tag = 0;
  
  
  
              if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
  
                  out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
      }
  
  system("pause");
  
      //Dump Format------------------
  
      printf("\n==============Input Video=============\n");
  
      av_dump_format(ifmt_ctx, 0, in_filename, 0);
  
      printf("\n==============Output Video============\n");
  
      av_dump_format(ofmt_ctx_v, 0, out_filename_v, 1);
  
      printf("\n==============Output Audio============\n");
  
      av_dump_format(ofmt_ctx_a, 0, out_filename_a, 1);
  
      printf("\n======================================\n");
  
      //Open output file
  
      if (!(ofmt_v->flags & AVFMT_NOFILE)) {
  
          if (avio_open(&ofmt_ctx_v->pb, out_filename_v, AVIO_FLAG_WRITE) < 0) {
  
              printf( "Could not open output file '%s'", out_filename_v);
  
              goto end;
  
          }
  
      }
  
  
  
      if (!(ofmt_a->flags & AVFMT_NOFILE)) {
  
          if (avio_open(&ofmt_ctx_a->pb, out_filename_a, AVIO_FLAG_WRITE) < 0) {
  
              printf( "Could not open output file '%s'", out_filename_a);
  
              goto end;
  
          }
  
      }
  
  
  
      //Write file header
  
      if (avformat_write_header(ofmt_ctx_v, NULL) < 0) {
  
          printf( "Error occurred when opening video output file\n");
  
          goto end;
  
      }
  
  
  
      if (avformat_write_header(ofmt_ctx_a, NULL) < 0) {
  
          printf( "Error occurred when opening audio output file\n");
  
          goto end;
  
      }
  
      system("pause");
  
  #if USE_H264BSF
  
      AVBitStreamFilterContext* h264bsfc =  av_bitstream_filter_init("h264_mp4toannexb"); 
  
  #endif
  
  
  
      while (1) {
  
          AVFormatContext *ofmt_ctx;
  
          AVStream *in_stream, *out_stream;
  
          //Get an AVPacket
  
          if (av_read_frame(ifmt_ctx, &pkt) < 0)
  
              break;
  
          in_stream  = ifmt_ctx->streams[pkt.stream_index];
  
  
  
  
  
          if(pkt.stream_index==videoindex){
  
              out_stream = ofmt_ctx_v->streams[0];
  
              ofmt_ctx=ofmt_ctx_v;
  
              #if USE_H264BSF
  
                  av_bitstream_filter_filter(h264bsfc, in_stream->codec, NULL, &pkt.data, &pkt.size, pkt.data, pkt.size, 0);
  
              #endif
  
              printf("Write Video Packet. size:%d\tpts:%lld\n",pkt.size,pkt.pts);
  
          }else if(pkt.stream_index==audioindex){
  
              out_stream = ofmt_ctx_a->streams[0];
  
              ofmt_ctx=ofmt_ctx_a;
  
              printf("Write Audio Packet. size:%d\tpts:%lld\n",pkt.size,pkt.pts);
  
          }else{
  
              continue;
  
          }
  
  
  
  
  
          //Convert PTS/DTS
  
          pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
  
          pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
  
          pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
  
          pkt.pos = -1;
  
          pkt.stream_index=0;
  
          //Write
  
          if (av_interleaved_write_frame(ofmt_ctx, &pkt) < 0) {
  
              printf( "Error muxing packet\n");
  
              break;
  
          }
  
          //printf("Write %8d frames to output file\n", frame_index);
  
          av_free_packet(&pkt);
  
          frame_index++;
  
      }
  
  system("pause");
  
  #if USE_H264BSF
  
      av_bitstream_filter_close(h264bsfc);  
  
  #endif
  
  
  
      //Write file trailer
  
      av_write_trailer(ofmt_ctx_a);
  
      av_write_trailer(ofmt_ctx_v);
  
  end:
  
      avformat_close_input(&ifmt_ctx);
  
      /* close output */
  
      if (ofmt_ctx_a && !(ofmt_a->flags & AVFMT_NOFILE))
  
          avio_close(ofmt_ctx_a->pb);
  
  
  
      if (ofmt_ctx_v && !(ofmt_v->flags & AVFMT_NOFILE))
  
          avio_close(ofmt_ctx_v->pb);
  
  
  
      avformat_free_context(ofmt_ctx_a);
  
      avformat_free_context(ofmt_ctx_v);
  
  
  
      system("pause");
  
      if (ret < 0 && ret != AVERROR_EOF) {
  
          printf( "Error occurred.\n");
  
          return -1;
  
      }
  
  
  
      return 0;
  
  }

  EDIT 1
  After reading through http://lists.libav.org/pipermail/libav-devel/2014-June/060048.html, I figured what was causing the "Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead". I fixed it by adding out_stream->time_base = in_stream->time_base; before the call to avformat_write_header. The code now runs without any error ! The h264 file created with the old FFMPEG (avcodec-55.dll) works fine while that created by the recent avcodec-57.dll is still invalid.

• C# FFMPEG : Code bugs out and stops producing media files

  24 mai 2020, par Hamez

  I've made a joke program in C# that uses ffmpeg to edit videos with different effects such as stuttering. I've finished 3 effects so far and each of them work on their own but as soon as I put one after another e.g.  fx.CrashStutter(0, 2); fx.CrashBeep(2, 2); fx.Wow(4, 2);
The code breaks and no longer produces photo/video files but once I stop debugging the file it was supposed to be processing appears. I've used a system where it loops over trying to execute a command to create a text file as a marker for when ffmpeg is done processing a file. The debug console also repeatedly says "The process tried to write to a nonexistent pipe."

  



  Here's the code for all 3 effects :

  



   public void Wow(double start, double duration)
        {
            if (fxstart == true)
            {
                //MessageBox.Show("WowFX Duration" + duration);
                string folderName = ("W_s" + start);
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("mkdir " + folderName);
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("cd " + folderName);
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("ffmpeg -ss " + start + " -t " + (duration / 6) + " -i " + source + " a.mp4");
                //wait until a.mp4 appears
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\a.txt") == false)
                {
                    /*aha got a live one!*/FXcmd.StandardInput.WriteLine(" echo a > a.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("ffmpeg -i a.mp4 -vf reverse -af areverse b.mp4");
                //wait until b.mp4 appears
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\b.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo b > b.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("ffmpeg -ss " + start + " -t " + (duration / 3) + " -i " + source + " c.mp4");
                //wait until c.mp4 appears
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\c.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo c > c.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("ffmpeg -i c.mp4 -vf reverse -af areverse d.mp4");
                //wait until d.mp4 appears
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\d.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo d > d.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                string[] concatList = { "file 'a.mp4'", "file 'b.mp4'", "file 'c.mp4'", "file 'd.mp4'" };
                //FXcmd.StandardInput.Write("del a.txt, b.txt, c.txt, d.txt");
                //System.Threading.Thread.Sleep(1000);
                System.IO.File.WriteAllLines(("FxSource(Temporary)\\" + folderName + "\\concatList.txt"), concatList);
                System.Threading.Thread.Sleep(1500);
                FXcmd.StandardInput.WriteLine("ffmpeg -f concat -i concatList.txt -c copy " + folderName + ".mp4");
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\" + "1.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo 1 > 1.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("copy " + folderName + ".mp4 ..");
                while (File.Exists("FxSource(Temporary)\\" + folderName + ".mp4") == false)
                {
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("cd ..");
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("cls");
                FXcmd.StandardInput.Flush();
            }
        }
        public void CrashStutter(int start, int duration)
        {
            if (fxstart == true)
            {
                string folderName = ("Cs_s" + start);
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("mkdir " + folderName);
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("cd " + folderName);
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("ffmpeg -ss " + start + " -t 0.1" + " -i " + source + " a.mp4");
                System.Threading.Thread.Sleep(100);
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\a.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo a > a.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("ffmpeg -stream_loop "+10*duration+" -i a.mp4 "+folderName+".mp4");
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\" + "1.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo 1 > 1.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("copy " + folderName + ".mp4 ..");
                while (File.Exists("FxSource(Temporary)\\" + folderName + ".mp4") == false)
                {
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("cd ..");
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("cls");
                FXcmd.StandardInput.Flush();
            }
        }
        public void CrashBeep(int start, int duration)
        {
            //this effect cannot last longer than 7 seconds
            double contrast = 25;
            double red = 0.75;
            if (fxstart == true)
            {
                string folderName = ("Cb_s" + start);
                FXcmd.StandardInput.WriteLine("mkdir " + folderName);
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("cd " + folderName);
                System.Threading.Thread.Sleep(100);
                /*gets stuck*/FXcmd.StandardInput.WriteLine("ffmpeg -i "+source+ " -vf fps=1 a.jpg");
                System.Threading.Thread.Sleep(100);
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\a.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo a > a.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("ffmpeg -i a.jpg -vf eq=contrast="+contrast+" b.jpg");
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\b.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo b > b.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("ffmpeg -i b.jpg -vf colorbalance=rm=" + red + " c.jpg");
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\c.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo > c.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("ffmpeg -loop 1 -i c.jpg -c:v libx264 -t "+ duration +" -pix_fmt yuv420p -vf scale=1920:1080 d.mp4");
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\d.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo d > d.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("cd ..");
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("copy beep.mp3 "+folderName+"/beep.mp3");
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("cd "+folderName);
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("ffmpeg -i beep.mp3 -ss 0 -t " + duration + " e.mp3");
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\e.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo e > e.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("ffmpeg -i d.mp4 -i e.mp3 -c copy -map 0:v:0 -map 1:a:0 " + folderName + ".mp4");
                while (File.Exists("FxSource(Temporary)\\" + folderName + "\\" + "1.txt") == false)
                {
                    FXcmd.StandardInput.WriteLine(" echo 1 > 1.txt");
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("copy " + folderName + ".mp4 ..");
                while (File.Exists("FxSource(Temporary)\\" + folderName + ".mp4") == false)
                {
                    System.Threading.Thread.Sleep(1500);
                }
                FXcmd.StandardInput.WriteLine("cd ..");
                System.Threading.Thread.Sleep(100);
                FXcmd.StandardInput.WriteLine("cls");
                FXcmd.StandardInput.Flush();
            }
        }


  



  Any suggestions ? Thanks !