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• How to record part of the Activity (ex : Linear layout ,relative layout) and export as a video ?

  22 avril 2019, par Elangovan S

  i want record a video from particular view. the example I have video view inside of my relative layout and text view, and I apply some animation to text view finally I want to record video both video view and text view and make a video. i tried ffmpeg continuously taking screenshot every frame and make a video but its not smooth , take too much time. is there any way to achieve this ? help me with this.

• Extracting the h264 part of a video file (demuxing)

  3 mars 2016, par MOHW

  I am trying to demux a video file into the video part (h264, mpeg4, h265, vp8, etc) and the audio part (mp3, aac, ac3, etc) and the subtitle part (srt) using ffmpeg in c++.

  The audio part came out alright and played on all the media players I have, so also did the subtitle part. The video part however came out WITHOUT error and saved into a .h264 file but when I use ffprobe to check it or ffplay to play it, it always give the error "Invalid data found when processing input".

  The code below

  /* Separate a media file into audio, video and subtitle files (demuxing, complex) */
  
  //TODO: mute error when subtitle is not present
  
  #define __STDC_CONSTANT_MACROS
  
  
  
  extern "C"
  
  {
  
      #include "libavformat/avformat.h"
  
  }
  
  
  
  
  
  int main()
  
  {
  
      //Input AVFormatContext and Output AVFormatContext
  
      AVOutputFormat *ofmt_a = NULL, *ofmt_v = NULL, *ofmt_s = NULL;
  
      AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx_a = NULL, *ofmt_ctx_v = NULL, *ofmt_ctx_s = NULL;
  
      AVPacket pkt;
  
  
  
      int ret, i;
  
      int videoindex=-1, audioindex=-1, srtindex=-1;
  
      int frame_index=0;
  
  
  
      //Input file URL
  
      const char *in_filename  = "sample.mp4";
  
  
  
      //Output file URL
  
      const char *out_filename_v = "sample.h264";
  
      const char *out_filename_a = "sample.mp3";
  
      const char *out_filename_s = "sample.srt";
  
  
  
      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;
  
      }
  
  
  
      //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;
  
  
  
      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;
  
  
  
      avformat_alloc_output_context2(&ofmt_ctx_s, NULL, NULL, out_filename_s);
  
      if (!ofmt_ctx_a) {
  
          printf( "Could not create output context\n");
  
          ret = AVERROR_UNKNOWN;
  
          goto end;
  
      }
  
      ofmt_s = ofmt_ctx_s->oformat;
  
  
  
      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 if(ifmt_ctx->streams[i]->codec->codec_type==AVMEDIA_TYPE_SUBTITLE){
  
                  srtindex=i;
  
                  out_stream=avformat_new_stream(ofmt_ctx_s, in_stream->codec->codec);
  
                  ofmt_ctx=ofmt_ctx_s;
  
              }
  
              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;
  
      }
  
  
  
      //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==============Output Subtitle============\n");
  
      av_dump_format(ofmt_ctx_s, 0, out_filename_s, 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;
  
          }
  
      }
  
      if (!(ofmt_a->flags & AVFMT_NOFILE)) {
  
          if (avio_open(&ofmt_ctx_s->pb, out_filename_s, AVIO_FLAG_WRITE) < 0) {
  
              printf( "Could not open output file '%s'", out_filename_s);
  
              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;
  
      }
  
      system("pause");
  
  
  
  
  
      if (avformat_write_header(ofmt_ctx_a, NULL) < 0) {
  
          printf( "Error occurred when opening audio output file\n");
  
          goto end;
  
      }
  
      if (avformat_write_header(ofmt_ctx_s, NULL) < 0) {
  
          printf( "Error occurred when opening audio output file\n");
  
          goto end;
  
      }
  
  
  
      AVBitStreamFilterContext* h264bsfc =  av_bitstream_filter_init("h264_mp4toannexb"); 
  
  
  
      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;
  
              printf("Write Video Packet. size:%d\tpts:%lld\n",pkt.size,pkt.pts);
  
              av_bitstream_filter_filter(h264bsfc, in_stream->codec, NULL, &pkt.data, &pkt.size, pkt.data, pkt.size, 0);
  
          }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 if(pkt.stream_index==srtindex){
  
              out_stream = ofmt_ctx_s->streams[0];
  
              ofmt_ctx=ofmt_ctx_s;
  
              printf("Write Subtitle 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++;
  
      }
  
  
  
      av_bitstream_filter_close(h264bsfc);  
  
  
  
      //Write file trailer
  
      av_write_trailer(ofmt_ctx_a);
  
      av_write_trailer(ofmt_ctx_v);
  
      av_write_trailer(ofmt_ctx_s);
  
  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);
  
  
  
      if (ofmt_ctx_s && !(ofmt_s->flags & AVFMT_NOFILE))
  
          avio_close(ofmt_ctx_s->pb);
  
  
  
      avformat_free_context(ofmt_ctx_a);
  
      avformat_free_context(ofmt_ctx_v);
  
      avformat_free_context(ofmt_ctx_s);
  
  
  
      system("pause");
  
      if (ret < 0 && ret != AVERROR_EOF) {
  
          printf( "Error occurred.\n");
  
          return -1;
  
      }
  
  
  
      return 0;
  
  }

  EDIT 1
  Screen shot of resultant h264 file
  

  EDIT 2
  I think the "error" has to do with FFMPEG’s "Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead" error.
  I revert to an older version of FFMPEG and with the same code, the resultant h264 file was ok !

• FFmpeg concat filter part 2

  16 juin 2020, par Narek Aydinyan

  I have videos. The video files have a different count of video tracks.

  



  video1 = 1 video stream + 1 audio stream.

  



  video2 = 2 video stream + 1 audio stream.

  



  The output result should be 2(concatenated) video streams, 1 audio stream.

  



  The same issue for the Audio case solved in my previous question(FFmpeg concat filter).
Also, I want to mark that I need to generate a video track with custom size.
For example, I can do this with color filter but this filter has fixed image sizes(https://ffmpeg.org/ffmpeg-utils.html#toc-Color) 
Thanks in advance