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• ffmpeg copyts to preserve timestamp

  13 April 2015, by Bala

  I am trying to modify an HLS segment transport stream, and preserve its start time with ffmpeg. However the output does not preserve the input file’s start_time value, even if -copyts is mentioned. Here’s my command line:

  ffmpeg  -i fileSequence1.ts -i x.png -filter_complex '[0:v][1:v]overlay[out]' -map '[out]' -map 0:1 -acodec copy -vsync 0 -vcodec libx264 -streamid 0:257 -streamid 1:258 -copyts -profile:v baseline -level 3 output.ts

  The start_time value is delayed about 2 seconds consistently.

  /Users/macadmin/>ffmpeg -y -v verbose -i fileSequence0.ts -map 0:0 -vcodec libx264 -copyts -vsync 0 -async 0 output.ts
  
  ffmpeg version 2.5.3 Copyright (c) 2000-2015 the FFmpeg developers
  
    built on Mar 29 2015 21:31:57 with Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.5.3 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid --enable-libfreetype --enable-libvorbis --enable-libvpx --enable-libass --enable-ffplay --enable-libfdk-aac --enable-libopus --enable-libquvi --enable-libx265 --enable-nonfree --enable-vda
  
    libavutil      54. 15.100 / 54. 15.100
  
    libavcodec     56. 13.100 / 56. 13.100
  
    libavformat    56. 15.102 / 56. 15.102
  
    libavdevice    56.  3.100 / 56.  3.100
  
    libavfilter     5.  2.103 /  5.  2.103
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  [h264 @ 0x7fa93b800000] Current profile doesn't provide more RBSP data in PPS, skipping
  
      Last message repeated 2 times
  
  [mpegts @ 0x7fa93a80da00] max_analyze_duration 5000000 reached at 5000000 microseconds
  
  Input #0, mpegts, from 'fileSequence0.ts':
  
    Duration: 00:00:09.65, start: 9.952111, bitrate: 412 kb/s
  
    Program 1 
  
      Stream #0:0[0x101]: Video: h264 (Constrained Baseline) ([27][0][0][0] / 0x001B), yuv420p, 640x360 (640x368), 25 fps, 25 tbr, 90k tbn, 50 tbc
  
      Stream #0:1[0x102]: Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp, 101 kb/s
  
  [graph 0 input from stream 0:0 @ 0x7fa93a5229c0] w:640 h:360 pixfmt:yuv420p tb:1/90000 fr:25/1 sar:0/1 sws_param:flags=2
  
  [libx264 @ 0x7fa93b800c00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  
  [libx264 @ 0x7fa93b800c00] profile High, level 3.0
  
  [mpegts @ 0x7fa93b800600] muxrate VBR, pcr every 2 pkts, sdt every 200, pat/pmt every 40 pkts
  
  Output #0, mpegts, to 'output.ts':
  
    Metadata:
  
      encoder         : Lavf56.15.102
  
      Stream #0:0: Video: h264 (libx264), yuv420p, 640x360, q=-1--1, 25 fps, 90k tbn, 25 tbc
  
      Metadata:
  
        encoder         : Lavc56.13.100 libx264
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  
  Press [q] to stop, [?] for help
  
  [NULL @ 0x7fa93b800000] Current profile doesn't provide more RBSP data in PPS, skipping
  
      Last message repeated 1 times
  
  frame=   87 fps=0.0 q=28.0 size=      91kB time=00:00:11.40 bitrate=  65.0kbits/[NULL @ 0x7fa93b800000] Current profile doesn't provide more RBSP data in PPS, skipping
  
  frame=  152 fps=151 q=28.0 size=     204kB time=00:00:14.00 bitrate= 119.4kbits/[NULL @ 0x7fa93b800000] Current profile doesn't provide more RBSP data in PPS, skipping
  
  frame=  224 fps=148 q=28.0 size=     306kB time=00:00:16.88 bitrate= 148.5kbits/No more output streams to write to, finishing.
  
  frame=  240 fps=125 q=-1.0 Lsize=     392kB time=00:00:19.52 bitrate= 164.6kbits/s    
  
  video:334kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 17.347548%
  
  Input file #0 (fileSequence0.ts):
  
    Input stream #0:0 (video): 240 packets read (360450 bytes); 240 frames decoded; 
  
    Input stream #0:1 (audio): 0 packets read (0 bytes); 
  
    Total: 240 packets (360450 bytes) demuxed
  
  Output file #0 (output.ts):
  
    Output stream #0:0 (video): 240 frames encoded; 240 packets muxed (342204 bytes); 
  
    Total: 240 packets (342204 bytes) muxed
  
  [libx264 @ 0x7fa93b800c00] frame I:3     Avg QP:15.08  size:  7856
  
  [libx264 @ 0x7fa93b800c00] frame P:81    Avg QP:21.03  size:  2807
  
  [libx264 @ 0x7fa93b800c00] frame B:156   Avg QP:23.40  size:   585
  
  [libx264 @ 0x7fa93b800c00] consecutive B-frames: 11.7%  2.5%  7.5% 78.3%
  
  [libx264 @ 0x7fa93b800c00] mb I  I16..4: 57.4% 17.5% 25.1%
  
  [libx264 @ 0x7fa93b800c00] mb P  I16..4:  8.0%  8.2%  1.0%  P16..4: 30.5% 11.3%  4.6%  0.0%  0.0%    skip:36.4%
  
  [libx264 @ 0x7fa93b800c00] mb B  I16..4:  0.1%  0.1%  0.0%  B16..8: 34.6%  2.7%  0.2%  direct: 1.3%  skip:60.9%  L0:47.3% L1:49.1% BI: 3.6%
  
  [libx264 @ 0x7fa93b800c00] 8x8 transform intra:42.2% inter:73.3%
  
  [libx264 @ 0x7fa93b800c00] coded y,uvDC,uvAC intra: 26.2% 43.0% 6.8% inter: 5.4% 8.5% 0.1%
  
  [libx264 @ 0x7fa93b800c00] i16 v,h,dc,p: 46% 26%  6% 21%
  
  [libx264 @ 0x7fa93b800c00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 50% 14% 23%  1%  2%  6%  1%  3%  1%
  
  [libx264 @ 0x7fa93b800c00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 40% 32% 10%  3%  3%  4%  2%  5%  2%
  
  [libx264 @ 0x7fa93b800c00] i8c dc,h,v,p: 48% 23% 26%  3%
  
  [libx264 @ 0x7fa93b800c00] Weighted P-Frames: Y:1.2% UV:0.0%
  
  [libx264 @ 0x7fa93b800c00] ref P L0: 71.5% 10.7% 14.8%  2.9%  0.1%
  
  [libx264 @ 0x7fa93b800c00] ref B L0: 95.5%  4.0%  0.5%
  
  [libx264 @ 0x7fa93b800c00] ref B L1: 96.8%  3.2%
  
  [libx264 @ 0x7fa93b800c00] kb/s:285.17
  
  
  
  ----------- FFProbe source video
  
  /Users/macadmin>ffprobe fileSequence0.ts
  
  ffprobe version 2.5.3 Copyright (c) 2007-2015 the FFmpeg developers
  
    built on Mar 29 2015 21:31:57 with Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.5.3 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid --enable-libfreetype --enable-libvorbis --enable-libvpx --enable-libass --enable-ffplay --enable-libfdk-aac --enable-libopus --enable-libquvi --enable-libx265 --enable-nonfree --enable-vda
  
    libavutil      54. 15.100 / 54. 15.100
  
    libavcodec     56. 13.100 / 56. 13.100
  
    libavformat    56. 15.102 / 56. 15.102
  
    libavdevice    56.  3.100 / 56.  3.100
  
    libavfilter     5.  2.103 /  5.  2.103
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, mpegts, from 'fileSequence0.ts':
  
    Duration: 00:00:09.65, start: 9.952111, bitrate: 412 kb/s
  
    Program 1 
  
      Stream #0:0[0x101]: Video: h264 (Constrained Baseline) ([27][0][0][0] / 0x001B), yuv420p, 640x360, 25 fps, 25 tbr, 90k tbn, 50 tbc
  
      Stream #0:1[0x102]: Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp, 101 kb/s
  
  
  
  ------ FFPROBE result video
  
  /Users/macadmin>ffprobe output.ts
  
  ffprobe version 2.5.3 Copyright (c) 2007-2015 the FFmpeg developers
  
    built on Mar 29 2015 21:31:57 with Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.5.3 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid --enable-libfreetype --enable-libvorbis --enable-libvpx --enable-libass --enable-ffplay --enable-libfdk-aac --enable-libopus --enable-libquvi --enable-libx265 --enable-nonfree --enable-vda
  
    libavutil      54. 15.100 / 54. 15.100
  
    libavcodec     56. 13.100 / 56. 13.100
  
    libavformat    56. 15.102 / 56. 15.102
  
    libavdevice    56.  3.100 / 56.  3.100
  
    libavfilter     5.  2.103 /  5.  2.103
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, mpegts, from 'output.ts':
  
    Duration: 00:00:09.60, start: 11.400000, bitrate: 334 kb/s
  
    Program 1 
  
      Metadata:
  
        service_name    : Service01
  
        service_provider: FFmpeg
  
      Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 640x360, 25 fps, 25 tbr, 90k tbn, 50 tbc

  How do I ensure that output file has the same start_time? Thanks.

• Output RTSP stream with ffmpeg

  28 July 2015, by sipwiz

  I’m attempting to use the ffmpeg libraries to send a video stream from my application to a media server (in this case wowza). I have been able to do the reverse and consume an RTSP stream but I’m having a few issues writing an RTSP stream.

  I have found a few examples and attempted to utilise the relevant bits. The code is below. I have simplified it as much as I can. I do only want to send a single H264 bit stream to the wowza server and which it can handle.

  I get an "Integer division by zero" exception whenever in the av_interleaved_write_frame function when I try and send a packet. The exception looks like it’s related to the packet timestamps not being set correctly. I’ve tried different values and can get past the exception by setting some contrived values but then the write call fails.

  #include <iostream>
  
  #include <fstream>
  
  #include <sstream>
  
  #include <cstring>
  
  
  
  #include "stdafx.h"
  
  #include "windows.h"
  
  
  
  extern "C"
  
  {
  
      #include 
  
      #include 
  
      #include 
  
      #include 
  
  }
  
  
  
  using namespace std;
  
  
  
  static int video_is_eof;
  
  
  
  #define STREAM_DURATION   50.0
  
  #define STREAM_FRAME_RATE 25 /* 25 images/s */
  
  #define STREAM_PIX_FMT    AV_PIX_FMT_YUV420P /* default pix_fmt */
  
  #define VIDEO_CODEC_ID CODEC_ID_H264
  
  
  
  static int sws_flags = SWS_BICUBIC;
  
  
  
  /* video output */
  
  static AVFrame *frame;
  
  static AVPicture src_picture, dst_picture;
  
  static int frame_count;
  
  
  
  static int write_frame(AVFormatContext *fmt_ctx, const AVRational *time_base, AVStream *st, AVPacket *pkt)
  
  {
  
      /* rescale output packet timestamp values from codec to stream timebase */
  
      pkt->pts = av_rescale_q_rnd(pkt->pts, *time_base, st->time_base, AVRounding(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
  
      pkt->dts = av_rescale_q_rnd(pkt->dts, *time_base, st->time_base, AVRounding(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
  
      pkt->duration = av_rescale_q(pkt->duration, *time_base, st->time_base);
  
  
  
      pkt->stream_index = st->index;
  
  
  
      // Exception occurs here.
  
      return av_interleaved_write_frame(fmt_ctx, pkt);
  
  }
  
  
  
  /* Add an output stream. */
  
  static AVStream *add_stream(AVFormatContext *oc, AVCodec **codec, enum AVCodecID codec_id)
  
  {
  
      AVCodecContext *c;
  
      AVStream *st;
  
  
  
      /* find the encoder */
  
      *codec = avcodec_find_encoder(codec_id);
  
      if (!(*codec)) {
  
          fprintf(stderr, "Could not find encoder for '%s'\n", avcodec_get_name(codec_id));
  
          exit(1);
  
      }
  
  
  
      st = avformat_new_stream(oc, *codec);
  
      if (!st) {
  
          fprintf(stderr, "Could not allocate stream\n");
  
          exit(1);
  
      }
  
  
  
      st->id = oc->nb_streams - 1;
  
      c = st->codec;
  
      c->codec_id = codec_id;
  
      c->bit_rate = 400000;
  
      c->width = 352;
  
      c->height = 288;
  
      c->time_base.den = STREAM_FRAME_RATE;
  
      c->time_base.num = 1;
  
      c->gop_size = 12; /* emit one intra frame every twelve frames at most */
  
      c->pix_fmt = STREAM_PIX_FMT;
  
  
  
      return st;
  
  }
  
  
  
  static void open_video(AVFormatContext *oc, AVCodec *codec, AVStream *st)
  
  {
  
      int ret;
  
      AVCodecContext *c = st->codec;
  
  
  
      /* open the codec */
  
      ret = avcodec_open2(c, codec, NULL);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Could not open video codec: ");
  
          exit(1);
  
      }
  
  
  
      /* allocate and init a re-usable frame */
  
      frame = av_frame_alloc();
  
      if (!frame) {
  
          fprintf(stderr, "Could not allocate video frame\n");
  
          exit(1);
  
      }
  
      frame->format = c->pix_fmt;
  
      frame->width = c->width;
  
      frame->height = c->height;
  
  
  
      /* Allocate the encoded raw picture. */
  
      ret = avpicture_alloc(&amp;dst_picture, c->pix_fmt, c->width, c->height);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Could not allocate picture: ");
  
          exit(1);
  
      }
  
  
  
      /* copy data and linesize picture pointers to frame */
  
      *((AVPicture *)frame) = dst_picture;
  
  }
  
  
  
  /* Prepare a dummy image. */
  
  static void fill_yuv_image(AVPicture *pict, int frame_index, int width, int height)
  
  {
  
      int x, y, i;
  
  
  
      i = frame_index;
  
  
  
      /* Y */
  
      for (y = 0; y &lt; height; y++)
  
          for (x = 0; x &lt; width; x++)
  
              pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
  
  
  
      /* Cb and Cr */
  
      for (y = 0; y &lt; height / 2; y++) {
  
          for (x = 0; x &lt; width / 2; x++) {
  
              pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
  
              pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
  
          }
  
      }
  
  }
  
  
  
  static void write_video_frame(AVFormatContext *oc, AVStream *st, int flush)
  
  {
  
      int ret;
  
      AVCodecContext *c = st->codec;
  
  
  
      if (!flush) {
  
          fill_yuv_image(&amp;dst_picture, frame_count, c->width, c->height);
  
      }
  
  
  
      AVPacket pkt = { 0 };
  
      int got_packet;
  
      av_init_packet(&amp;pkt);
  
  
  
      /* encode the image */
  
      frame->pts = frame_count;
  
      ret = avcodec_encode_video2(c, &amp;pkt, flush ? NULL : frame, &amp;got_packet);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Error encoding video frame:");
  
          exit(1);
  
      }
  
      /* If size is zero, it means the image was buffered. */
  
  
  
      if (got_packet) {
  
          ret = write_frame(oc, &amp;c->time_base, st, &amp;pkt);
  
      }
  
      else {
  
          if (flush) {
  
              video_is_eof = 1;
  
          }
  
          ret = 0;
  
      }
  
  
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Error while writing video frame: ");
  
          exit(1);
  
      }
  
      frame_count++;
  
  }
  
  
  
  static void close_video(AVFormatContext *oc, AVStream *st)
  
  {
  
      avcodec_close(st->codec);
  
      av_free(src_picture.data[0]);
  
      av_free(dst_picture.data[0]);
  
      av_frame_free(&amp;frame);
  
  }
  
  
  
  int _tmain(int argc, _TCHAR* argv[])
  
  {
  
      printf("starting...\n");
  
  
  
      const char *filename = "rtsp://test:password@192.168.33.19:1935/ffmpeg/0";
  
  
  
      AVOutputFormat *fmt;
  
      AVFormatContext *oc;
  
      AVStream *video_st;
  
      AVCodec *video_codec;
  
      double video_time;
  
      int flush, ret;
  
  
  
      /* Initialize libavcodec, and register all codecs and formats. */
  
      av_register_all();
  
      avformat_network_init();
  
  
  
      AVOutputFormat* oFmt = av_oformat_next(NULL);
  
      while (oFmt) {
  
          if (oFmt->video_codec == VIDEO_CODEC_ID) {
  
              break;
  
          }
  
          oFmt = av_oformat_next(oFmt);
  
      }
  
  
  
      if (!oFmt) {
  
          printf("Could not find the required output format.\n");
  
          exit(1);
  
      }
  
  
  
      /* allocate the output media context */
  
      avformat_alloc_output_context2(&amp;oc, oFmt, "rtsp", filename);
  
  
  
      if (!oc) {
  
          printf("Could not set the output media context.\n");
  
          exit(1);
  
      }
  
  
  
      fmt = oc->oformat;
  
      if (!fmt) {
  
          printf("Could not create the output format.\n");
  
          exit(1);
  
      }
  
  
  
      video_st = NULL;
  
  
  
      cout &lt;&lt; "Codec = " &lt;&lt; avcodec_get_name(fmt->video_codec) &lt;&lt; endl;
  
      if (fmt->video_codec != AV_CODEC_ID_NONE)
  
      {
  
          video_st = add_stream(oc, &amp;video_codec, fmt->video_codec);
  
      }
  
  
  
      /* Now that all the parameters are set, we can open the video codec and allocate the necessary encode buffers. */
  
      if (video_st) {
  
          open_video(oc, video_codec, video_st);
  
      }
  
  
  
      av_dump_format(oc, 0, filename, 1);
  
      char errorBuff[80];
  
  
  
      if (!(fmt->flags &amp; AVFMT_NOFILE)) {
  
          ret = avio_open(&amp;oc->pb, filename, AVIO_FLAG_WRITE);
  
          if (ret &lt; 0) {
  
              fprintf(stderr, "Could not open outfile '%s': %s", filename, av_make_error_string(errorBuff, 80, ret));
  
              return 1;
  
          }
  
      }
  
  
  
      flush = 0;
  
      while (video_st &amp;&amp; !video_is_eof) {
  
          /* Compute current video time. */
  
          video_time = (video_st &amp;&amp; !video_is_eof) ? video_st->pts.val * av_q2d(video_st->time_base) : INFINITY;
  
  
  
          if (!flush &amp;&amp; (!video_st || video_time >= STREAM_DURATION)) {
  
              flush = 1;
  
          }
  
  
  
          if (video_st &amp;&amp; !video_is_eof) {
  
              write_video_frame(oc, video_st, flush);
  
          }
  
      }
  
  
  
      if (video_st) {
  
          close_video(oc, video_st);
  
      }
  
  
  
      if ((fmt->flags &amp; AVFMT_NOFILE)) {
  
          avio_close(oc->pb);
  
      }
  
  
  
      avformat_free_context(oc);
  
  
  
      printf("finished.\n");
  
  
  
      getchar();
  
  
  
      return 0;
  
  }
  
  </cstring></sstream></fstream></iostream>

  Does anyone have any insights about how the packet timestamps can be successfully set?

• Issue when combining 2 video files [after matching the specs]

  6 December 2015, by Rune

  Basically I got a .mp4 and a .flv file which I want to concatenate (the .mp4 should be the intro).

  So after having asked a previous question regarding this I went ahead and converted the intro video to an .flv with matching specifications of the second video.

  First I got the specifications of the second (.flv) video using ffprobe. This was the output:

  {
  
      "streams": [
  
          {
  
              "index": 0,
  
              "codec_name": "h264",
  
              "codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
  
              "profile": "High",
  
              "codec_type": "video",
  
              "codec_time_base": "1/50",
  
              "codec_tag_string": "[0][0][0][0]",
  
              "codec_tag": "0x0000",
  
              "width": 646,
  
              "height": 364,
  
              "coded_width": 656,
  
              "coded_height": 368,
  
              "has_b_frames": 2,
  
              "sample_aspect_ratio": "1:1",
  
              "display_aspect_ratio": "323:182",
  
              "pix_fmt": "yuv420p",
  
              "level": 30,
  
              "chroma_location": "left",
  
              "refs": 5,
  
              "is_avc": "true",
  
              "nal_length_size": "4",
  
              "r_frame_rate": "25/1",
  
              "avg_frame_rate": "25/1",
  
              "time_base": "1/1000",
  
              "start_pts": 80,
  
              "start_time": "0.080000",
  
              "bit_rate": "400000",
  
              "bits_per_raw_sample": "8",
  
              "disposition": {
  
                  "default": 0,
  
                  "dub": 0,
  
                  "original": 0,
  
                  "comment": 0,
  
                  "lyrics": 0,
  
                  "karaoke": 0,
  
                  "forced": 0,
  
                  "hearing_impaired": 0,
  
                  "visual_impaired": 0,
  
                  "clean_effects": 0,
  
                  "attached_pic": 0
  
              }
  
          },
  
          {
  
              "index": 1,
  
              "codec_name": "aac",
  
              "codec_long_name": "AAC (Advanced Audio Coding)",
  
              "profile": "LC",
  
              "codec_type": "audio",
  
              "codec_time_base": "1/44100",
  
              "codec_tag_string": "[0][0][0][0]",
  
              "codec_tag": "0x0000",
  
              "sample_fmt": "fltp",
  
              "sample_rate": "44100",
  
              "channels": 2,
  
              "channel_layout": "stereo",
  
              "bits_per_sample": 0,
  
              "r_frame_rate": "0/0",
  
              "avg_frame_rate": "0/0",
  
              "time_base": "1/1000",
  
              "start_pts": 241,
  
              "start_time": "0.241000",
  
              "bit_rate": "96000",
  
              "disposition": {
  
                  "default": 0,
  
                  "dub": 0,
  
                  "original": 0,
  
                  "comment": 0,
  
                  "lyrics": 0,
  
                  "karaoke": 0,
  
                  "forced": 0,
  
                  "hearing_impaired": 0,
  
                  "visual_impaired": 0,
  
                  "clean_effects": 0,
  
                  "attached_pic": 0
  
              }
  
          }
  
      ],
  
      "format": {
  
          "filename": "vid2.flv",
  
          "nb_streams": 2,
  
          "nb_programs": 0,
  
          "format_name": "flv",
  
          "format_long_name": "FLV (Flash Video)",
  
          "start_time": "0.080000",
  
          "duration": "371.920000",
  
          "size": "23876671",
  
          "bit_rate": "513587",
  
          "probe_score": 100,
  
          "tags": {
  
              "audiosize": "4476626",
  
              "canSeekToEnd": "true",
  
              "datasize": "23876671",
  
              "videosize": "19004263",
  
              "hasAudio": "true",
  
              "hasCuePoints": "false",
  
              "hasKeyframes": "true",
  
              "hasMetadata": "true",
  
              "hasVideo": "true",
  
              "lasttimestamp": "372",
  
              "metadatacreator": "flvtool++ (Facebook, Motion project, dweatherford)",
  
              "totalframes": "9298",
  
              "encoder": "Lavf56.36.100"
  
          }
  
      }
  
  }

  Here’s my command:

  -i prefix.mp4 -b:v 400k -b:a 96k -r 25 -ar 44100 -acodec aac -vf scale=646:364 -strict -2 prefix.flv.

  This produces the following output (as well as the video file):

  ffmpeg version N-76137-gb0bb1dc Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 5.2.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enable-zlib
  
    libavutil      55.  4.100 / 55.  4.100
  
    libavcodec     57.  7.100 / 57.  7.100
  
    libavformat    57.  8.102 / 57.  8.102
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 12.100 /  6. 12.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.100 /  2.  0.100
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'prefix.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.8.102
  
    Duration: 00:00:05.31, start: 0.000000, bitrate: 1589 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 1205 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 384 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  Output #0, flv, to 'prefix.flv':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.8.102
  
      Stream #0:0(und): Video: flv1 (flv) ([2][0][0][0] / 0x0002), yuv420p, 646x364 [SAR 2912:2907 DAR 16:9], q=2-31, 400 kb/s, 25 fps, 1k tbn, 25 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
        encoder         : Lavc57.7.100 flv
  
      Stream #0:1(und): Audio: aac ([10][0][0][0] / 0x000A), 44100 Hz, 5.1, fltp, 96 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
        encoder         : Lavc57.7.100 aac
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> flv1 (flv))
  
    Stream #0:1 -> #0:1 (aac (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  frame=   79 fps=0.0 q=10.7 size=     381kB time=00:00:03.43 bitrate= 908.7kbits/frame=  132 fps=0.0 q=10.1 Lsize=     548kB time=00:00:05.31 bitrate= 844.1kbits/s
  
  video:479kB audio:62kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.161623%
  
  [aac @ 0000021aa893eae0] Qavg: 177.292

  I then run the outputted video file and it runs just like the old one.

  I then concatenate the ouputted intro file with my main video file using the following command (tmp.txt contains the 2 files):

  -f concat -i tmp.txt -c copy newvid.flv

  This produces the following output:

  ffmpeg version N-76137-gb0bb1dc Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 5.2.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enable-zlib
  
    libavutil      55.  4.100 / 55.  4.100
  
    libavcodec     57.  7.100 / 57.  7.100
  
    libavformat    57.  8.102 / 57.  8.102
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 12.100 /  6. 12.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.100 /  2.  0.100
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, concat, from 'tmp.txt':
  
    Duration: N/A, start: 0.000000, bitrate: 496 kb/s
  
      Stream #0:0: Video: flv1, yuv420p, 646x364, 400 kb/s, 25 fps, 25 tbr, 1k tbn, 1k tbc
  
      Stream #0:1: Audio: aac (LC), 44100 Hz, 5.1, fltp, 96 kb/s
  
  [flv @ 00000257b5f0e180] Codec for stream 0 does not use global headers but container format requires global headers
  
  [flv @ 00000257b5f0e180] Codec for stream 1 does not use global headers but container format requires global headers
  
  Output #0, flv, to 'newvid.flv':
  
    Metadata:
  
      encoder         : Lavf57.8.102
  
      Stream #0:0: Video: flv1 ([2][0][0][0] / 0x0002), yuv420p, 646x364, q=2-31, 400 kb/s, 25 fps, 25 tbr, 1k tbn, 1k tbc
  
      Stream #0:1: Audio: aac ([10][0][0][0] / 0x000A), 44100 Hz, 5.1, 96 kb/s
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
    Stream #0:1 -> #0:1 (copy)
  
  Press [q] to stop, [?] for help
  
  [flv @ 00000257b56947e0] Packet mismatch 486539264 7424
  
  [flv @ 00000257b56947e0] Auto-inserting h264_mp4toannexb bitstream filter
  
  [flv @ 00000257b5f0e180] Non-monotonous DTS in output stream 0:0; previous: 5263, current: 5255; changing to 5263. This may result in incorrect timestamps in the output file.
  
  frame= 6359 fps=0.0 q=-1.0 size=   15906kB time=00:04:14.30 bitrate= 512.4kbits/frame= 9428 fps=0.0 q=-1.0 Lsize=   23835kB time=00:06:17.05 bitrate= 517.8kbits/s
  
  video:19016kB audio:4403kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.777447%

  When I try to run the final video (newvid.flv) it plays like this:

  It starts off playing the intro just fine.
  However, when the intro is finished the video freezes while the sound of the actual video continues for the entire duration of the video.

  Thus in conclusion what is lacking is the video of the second vid (the audio is fine).

  I’m new at using ffmpeg but I’ve tried my best to solve this, which is why I’m asking for your help.

  I’d certainly appreciate if someone could help me out.