mpegts muxer creates non-zero start time

[slhck]

$ ffmpeg -i BigBuckBunny-trailer-1080p.ogg -c:v libx264 -t 2 -an -f mpegts out.ts
ffmpeg version N-65018-gad91bf8 Copyright (c) 2000-2014 the FFmpeg developers
  built on Jul 26 2014 22:09:15 with gcc 4.8.3 (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-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-decklink --enable-zlib
  libavutil      52. 92.101 / 52. 92.101
  libavcodec     55. 69.100 / 55. 69.100
  libavformat    55. 49.100 / 55. 49.100
  libavdevice    55. 13.102 / 55. 13.102
  libavfilter     4. 11.102 /  4. 11.102
  libswscale      2.  6.100 /  2.  6.100
  libswresample   0. 19.100 /  0. 19.100
  libpostproc    52.  3.100 / 52.  3.100
[theora @ 00000000002fffe0] 7 bits left in packet 82
Input #0, ogg, from 'BigBuckBunny-trailer-1080p.ogg':
  Duration: 00:00:33.00, start: 0.000000, bitrate: 6757 kb/s
    Stream #0:0: Video: theora, yuv420p(bt470bg), 1920x1080, 25 fps, 25 tbr, 25 tbn, 25 tbc
    Metadata:
      ENCODER         : ffmpeg2theora 0.19
    Stream #0:1: Audio: vorbis, 48000 Hz, stereo, fltp, 80 kb/s
    Metadata:
      ENCODER         : ffmpeg2theora 0.19
[libx264 @ 00000000051ebac0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 00000000051ebac0] profile High, level 4.0
[theora @ 00000000003bf7e0] 7 bits left in packet 82
Output #0, mpegts, to 'out.ts':
  Metadata:
    encoder         : Lavf55.49.100
    Stream #0:0: Video: h264 (libx264), yuv420p, 1920x1080, q=-1--1, 25 fps, 90k tbn, 25 tbc
    Metadata:
      encoder         : Lavc55.69.100 libx264
Stream mapping:
  Stream #0:0 -> #0:0 (theora (native) -> h264 (libx264))
Press [q] to stop, [?] for help
frame=   50 fps= 30 q=-1.0 Lsize=     122kB time=00:00:01.92 bitrate= 520.9kbits/s
video:107kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 14.412790%
[libx264 @ 00000000051ebac0] frame I:1     Avg QP:18.79  size:  1317
[libx264 @ 00000000051ebac0] frame P:15    Avg QP:16.73  size:  4627
[libx264 @ 00000000051ebac0] frame B:34    Avg QP:20.98  size:  1134
[libx264 @ 00000000051ebac0] consecutive B-frames:  8.0%  4.0%  0.0% 88.0%
[libx264 @ 00000000051ebac0] mb I  I16..4:  0.0% 100.0%  0.0%
[libx264 @ 00000000051ebac0] mb P  I16..4:  3.9%  2.8%  0.3%  P16..4:  5.0%  1.3%  0.7%  0.0%  0.0%    skip:86.1%
[libx264 @ 00000000051ebac0] mb B  I16..4:  1.0%  0.5%  0.0%  B16..8: 10.3%  0.3%  0.0%  direct: 0.2%  skip:87.8%  L0:51.2% L1:45.8% BI: 3.0%
[libx264 @ 00000000051ebac0] 8x8 transform intra:62.2% inter:74.1%
[libx264 @ 00000000051ebac0] coded y,uvDC,uvAC intra: 3.0% 6.7% 3.9% inter: 0.6% 1.2% 0.6%
[libx264 @ 00000000051ebac0] i16 v,h,dc,p: 27% 72%  0%  0%
[libx264 @ 00000000051ebac0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  3% 65% 30%  1%  0%  0%  0%  0%  1%
[libx264 @ 00000000051ebac0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 48% 26% 17%  2%  2%  2%  1%  1%  1%
[libx264 @ 00000000051ebac0] i8c dc,h,v,p: 90%  4%  6%  0%
[libx264 @ 00000000051ebac0] Weighted P-Frames: Y:40.0% UV:40.0%
[libx264 @ 00000000051ebac0] ref P L0: 72.3%  6.1% 13.9%  6.4%  1.2%
[libx264 @ 00000000051ebac0] ref B L0: 71.8% 22.3%  5.9%
[libx264 @ 00000000051ebac0] ref B L1: 88.1% 11.9%
[libx264 @ 00000000051ebac0] kb/s:437.08

When inspecting the output file:

$ ffprobe -select_streams v -show_frames -of compact -show_entries frame=pict_type,pkt_pts_time out.ts
frame|pkt_pts_time=1.480000|pict_type=I
frame|pkt_pts_time=1.520000|pict_type=B
frame|pkt_pts_time=1.560000|pict_type=B
frame|pkt_pts_time=1.600000|pict_type=B
frame|pkt_pts_time=1.640000|pict_type=P
frame|pkt_pts_time=1.680000|pict_type=B
frame|pkt_pts_time=1.720000|pict_type=B
frame|pkt_pts_time=1.760000|pict_type=B
frame|pkt_pts_time=1.800000|pict_type=P
frame|pkt_pts_time=1.840000|pict_type=B
frame|pkt_pts_time=1.880000|pict_type=B
frame|pkt_pts_time=1.920000|pict_type=B
frame|pkt_pts_time=1.960000|pict_type=P
frame|pkt_pts_time=2.000000|pict_type=B
frame|pkt_pts_time=2.040000|pict_type=P
frame|pkt_pts_time=2.080000|pict_type=P
frame|pkt_pts_time=2.120000|pict_type=P
frame|pkt_pts_time=2.160000|pict_type=B
frame|pkt_pts_time=2.200000|pict_type=B
frame|pkt_pts_time=2.240000|pict_type=B
frame|pkt_pts_time=2.280000|pict_type=P
frame|pkt_pts_time=2.320000|pict_type=P
frame|pkt_pts_time=2.360000|pict_type=B
frame|pkt_pts_time=2.400000|pict_type=B
frame|pkt_pts_time=2.440000|pict_type=B
frame|pkt_pts_time=2.480000|pict_type=P
frame|pkt_pts_time=2.520000|pict_type=B
frame|pkt_pts_time=2.560000|pict_type=B
frame|pkt_pts_time=2.600000|pict_type=B
frame|pkt_pts_time=2.640000|pict_type=P
frame|pkt_pts_time=2.680000|pict_type=B
frame|pkt_pts_time=2.720000|pict_type=B
frame|pkt_pts_time=2.760000|pict_type=B
frame|pkt_pts_time=2.800000|pict_type=P
frame|pkt_pts_time=2.840000|pict_type=B
frame|pkt_pts_time=2.880000|pict_type=B
frame|pkt_pts_time=2.920000|pict_type=B
frame|pkt_pts_time=2.960000|pict_type=P
frame|pkt_pts_time=3.000000|pict_type=B
frame|pkt_pts_time=3.040000|pict_type=B
frame|pkt_pts_time=3.080000|pict_type=B
frame|pkt_pts_time=3.120000|pict_type=P
frame|pkt_pts_time=3.160000|pict_type=B
frame|pkt_pts_time=3.200000|pict_type=B
frame|pkt_pts_time=3.240000|pict_type=B
frame|pkt_pts_time=3.280000|pict_type=P
frame|pkt_pts_time=3.320000|pict_type=B
frame|pkt_pts_time=3.360000|pict_type=B
frame|pkt_pts_time=3.400000|pict_type=B
frame|pkt_pts_time=3.440000|pict_type=P
ffprobe version N-65018-gad91bf8 Copyright (c) 2007-2014 the FFmpeg developers
  built on Jul 26 2014 22:09:15 with gcc 4.8.3 (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-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-decklink --enable-zlib
  libavutil      52. 92.101 / 52. 92.101
  libavcodec     55. 69.100 / 55. 69.100
  libavformat    55. 49.100 / 55. 49.100
  libavdevice    55. 13.102 / 55. 13.102
  libavfilter     4. 11.102 /  4. 11.102
  libswscale      2.  6.100 /  2.  6.100
  libswresample   0. 19.100 /  0. 19.100
  libpostproc    52.  3.100 / 52.  3.100
Input #0, mpegts, from 'out.ts':
  Duration: 00:00:02.00, start: 1.480000, bitrate: 500 kb/s
  Program 1
    Metadata:
      service_name    : Service01
      service_provider: FFmpeg
    Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 1920x1080, 25 fps, 25 tbr, 90k tbn, 50 tbc

One would expect the output transport stream to start with zero PTS, not some arbitrary (?) offset.

With MP4 as container though, PTS start with 0.

[Kieran Kunhya]

Read the TS spec. A zero PTS is meaningless in MPEG-TS.