title: ffmpeg copyts to preserve timestamp
body: <p>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: </p>
  
  <pre><code>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
  </code></pre>
  
  <p>The start_time value is delayed about 2 seconds consistently.</p>
  
  <pre><code>/Users/macadmin/&gt;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 -&gt; #0:0 (h264 (native) -&gt; 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&gt;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&gt;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
  </code></pre>
  
  <p>How do I ensure that output file has the same start_time? Thanks.</p>