[FFmpeg-user] DTS discontinuity

[Mark Filipak]

Hi All,

I have problems with stream 0:2 (the subtitles). The problem ruins to-SRT conversions later in the 
work-flow. Also, stream 0:2 winds up with no duration and that screws up concatenations.

A typical notice is "DTS discontinuity in stream 2: packet 12 with DTS 12859568".

I'm trimming, then concatenating the segments. I'm used to working in 'N' & 'DTS' & 'PTS' for the 
trimming and the concatenations. I'm successful for video & audio, but subs are creating problems.

I'd appreciate some wisdom regarding how to fix the 'discontinuity' issues. I have not found a 
'showinfo' equivalent for subtitles.

The log below is a version I cooked up to show 'N' only for I-frames.

Thanks -- Mark.

ffprobe version 2023-11-09-git-acf63d5350-full_build-www.gyan.dev Copyright (c) 2007-2023 the FFmpeg 
developers
   built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
   configuration: --enable-gpl --enable-version3 --enable-static --pkg-config=pkgconf 
--disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls 
--enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib 
--enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth 
--enable-libbluray --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libaribcaption 
--enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e 
--enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 
--enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx 
--enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi 
--enable-libharfbuzz --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg 
--enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc 
--enable-dxva2 --enable-d3d11va --enable-libvpl --enable-libshaderc --enable-vulkan 
--enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug 
--enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine 
--enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc 
--enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis 
--enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband 
--enable-libsoxr --enable-chromaprint
   libavutil      58. 32.100 / 58. 32.100
   libavcodec     60. 33.100 / 60. 33.100
   libavformat    60. 17.100 / 60. 17.100
   libavdevice    60.  4.100 / 60.  4.100
   libavfilter     9. 13.100 /  9. 13.100
   libswscale      7.  6.100 /  7.  6.100
   libswresample   4. 13.100 /  4. 13.100
   libpostproc    57.  4.100 / 57.  4.100
[mpegts @ 00000000003ad440] DTS discontinuity in stream 2: packet 12 with DTS 12859568, packet 13 
with DTS 12970433
[mpegts @ 00000000003ad440] DTS discontinuity in stream 2: packet 20 with DTS 13302507, packet 21 
with DTS 13417133
[mpegts @ 00000000003ad440] DTS discontinuity in stream 2: packet 28 with DTS 14965402, packet 29 
with DTS 15080059
[mpegts @ 00000000003ad440] DTS discontinuity in stream 2: packet 36 with DTS 15502195, packet 37 
with DTS 15613087
[mpegts @ 00000000003ad440] DTS discontinuity in stream 2: packet 44 with DTS 19788998, packet 45 
with DTS 19903601
[mpegts @ 00000000003ad440] DTS discontinuity in stream 2: packet 52 with DTS 21207988, packet 53 
with DTS 21543919
Input #0, mpegts, from 'H:\BDMV\STREAM\00305.m2ts':
   Duration: 01:36:12.73, start: 11.650667, bitrate: 20913 kb/s
   Program 1
   Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p(progressive), 1920x1080 [SAR 
1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 90k tbn
   Stream #0:1[0x1100]: Audio: dts (DTS-HD MA) ([134][0][0][0] / 0x0086), 48000 Hz, mono, s32p (24 bit)
   Stream #0:2[0x1200]: Subtitle: hdmv_pgs_subtitle ([144][0][0][0] / 0x0090), 1920x1080
frames.frame.0.key_frame=1
frames.frame.26.key_frame=1
frames.frame.50.key_frame=1