[FFmpeg-user] reserve output stream for delayed subtitles ?

sean darcy seandarcy2 at gmail.com
Wed Nov 21 22:23:01 EET 2018 

I have a 1949 french movie. I need the subtitles, my french isn't good 
enough any more !

The problem is that the subtitles stream doesn't start until 85 seconds 
into the movie. I've map'd the subtitle stream , but the output stream 
isn't created. I assume that's because there's no input subtitles stream 
at the start.

I've tried:
ffmpeg -i in -ss 00:01:30 -i in -map 0:1 -map 0:2 -map 1:4 .... but that 
didn't work since ffmpeg still looked for the subtitles stream at the 
beginning, not at the seek position. In any event I think that would 
have had the subtitles appearing 90 secs before the dialog.


long output. You can see the subtitle streams appear at 85 secs.

ffmpeg -i VTS_01_1.VOB -r 24000/1001 -map v -map a -map 0:4 -c:v libx264 
-crf 20 -tune film -preset slow -c:a copy -c:s copy -dn -t 00:02:00 
short-1949-subs.mp4
ffmpeg version git-snapshot-20181112-RPMFusion Copyright (c) 2000-2018 
the FFmpeg developers
   built with gcc 8 (GCC)
   configuration: --prefix=/usr --bindir=/usr/bin 
--datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg 
--libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 
--optflags='-O2 -ffast-math -march=native -ftree-vectorize 
-fomit-frame-pointer -pipe -fPIC' --enable-bzlib --disable-crystalhd 
--enable-fontconfig --enable-frei0r --enable-gcrypt --enable-gnutls 
--enable-ladspa --enable-libass --enable-libbluray --enable-libcdio 
--enable-libdav1d --enable-libfdk-aac --enable-nonfree 
--enable-indev=jack --enable-libfreetype --enable-libfribidi 
--enable-libgsm --enable-libmp3lame --enable-openal --enable-opencl 
--disable-libopencv --enable-opengl --enable-libopenjpeg 
--enable-libopus --enable-libpulse --enable-libsoxr --enable-libspeex 
--enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvpx 
--enable-libwebp --enable-libx264 --enable-libx265 --enable-avfilter 
--enable-postproc --enable-pthreads --disable-static --enable-shared 
--enable-gpl --enable-version3 --enable-nonfree --disable-debug 
--enable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
   libavutil      56. 23.101 / 56. 23.101
   libavcodec     58. 39.100 / 58. 39.100
   libavformat    58. 22.100 / 58. 22.100
   libavdevice    58.  6.100 / 58.  6.100
   libavfilter     7. 43.100 /  7. 43.100
   libswscale      5.  4.100 /  5.  4.100
   libswresample   3.  4.100 /  3.  4.100
   libpostproc    55.  4.100 / 55.  4.100
Input #0, mpeg, from 'VTS_01_1.VOB':
   Duration: 00:29:44.30, start: 0.045500, bitrate: 4814 kb/s
     Stream #0:0[0x1bf]: Data: dvd_nav_packet
     Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, 
progressive), 720x480 [SAR 8:9 DAR 4:3], Closed Captions, 29.33 fps, 
59.94 tbr, 90k tbn, 59.94 tbc
     Stream #0:2[0x80]: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
Stream mapping:
   Stream #0:1 -> #0:0 (mpeg2video (native) -> h264 (libx264))
   Stream #0:2 -> #0:1 (copy)
Press [q] to stop, [?] for help
[libx264 @ 0x149cf40] using SAR=8/9
[libx264 @ 0x149cf40] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 
AVX FMA3 BMI2 AVX2
[libx264 @ 0x149cf40] profile High, level 3.0, 4:2:0, 8-bit
[libx264 @ 0x149cf40] 264 - core 157 - H.264/MPEG-4 AVC codec - Copyleft 
2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=5 
deblock=1:-1:-1 analyse=0x3:0x113 me=hex subme=8 psy=1 psy_rd=1.00:0.15 
mixed_ref=1 me_range=16 chroma_me=1 trellis=2 8x8dct=1 cqm=0 
deadzone=21,11 fast_pskip=1 chroma_qp_offset=-3 threads=12 
lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 
bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 
b_bias=0 direct=3 weightb=1 open_gop=0 weightp=2 keyint=250 
keyint_min=23 scenecut=40 intra_refresh=0 rc_lookahead=50 rc=crf 
mbtree=1 crf=20.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 
aq=1:1.00
[mp4 @ 0x1470840] track 1: codec frame size is not set
Output #0, mp4, to 'short--1949-subs.mp4':
   Metadata:
     encoder         : Lavf58.22.100
     Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 
720x480 [SAR 8:9 DAR 4:3], q=-1--1, 23.98 fps, 24k tbn, 23.98 tbc
     Metadata:
       encoder         : Lavc58.39.100 libx264
     Side data:
       cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
     Stream #0:1: Audio: ac3 (ac-3 / 0x332D6361), 48000 Hz, stereo, 
fltp, 192 kb/s
[mpeg2video @ 0x14723c0] ac-tex damaged at 38 2500:01:03.64 
bitrate=3459.7kbits/s dup=1 drop=0 speed=3.63x
[mpeg2video @ 0x14723c0] Warning MVs not available
[mpeg2video @ 0x14723c0] concealing 225 DC, 225 AC, 225 MV errors in I frame
[mpeg @ 0x1469c40] New subtitle stream 0:3 at pos:50339854 and 
DTS:87.4328sbits/s dup=1 drop=0 speed= 3.3x
[mpeg @ 0x1469c40] New subtitle stream 0:4 at pos:50493454 and DTS:87.6664s
..........

ffprobe short-1949-subs.mp4
ffprobe version git-snapshot-20181112-RPMFusion Copyright (c) 2007-2018 
the FFmpeg developers
   built with gcc 8 (GCC)
   configuration: --prefix=/usr --bindir=/usr/bin 
--datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg 
--libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 
--optflags='-O2 -ffast-math -march=native -ftree-vectorize 
-fomit-frame-pointer -pipe -fPIC' --enable-bzlib --disable-crystalhd 
--enable-fontconfig --enable-frei0r --enable-gcrypt --enable-gnutls 
--enable-ladspa --enable-libass --enable-libbluray --enable-libcdio 
--enable-libdav1d --enable-libfdk-aac --enable-nonfree 
--enable-indev=jack --enable-libfreetype --enable-libfribidi 
--enable-libgsm --enable-libmp3lame --enable-openal --enable-opencl 
--disable-libopencv --enable-opengl --enable-libopenjpeg 
--enable-libopus --enable-libpulse --enable-libsoxr --enable-libspeex 
--enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvpx 
--enable-libwebp --enable-libx264 --enable-libx265 --enable-avfilter 
--enable-postproc --enable-pthreads --disable-static --enable-shared 
--enable-gpl --enable-version3 --enable-nonfree --disable-debug 
--enable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
   libavutil      56. 23.101 / 56. 23.101
   libavcodec     58. 39.100 / 58. 39.100
   libavformat    58. 22.100 / 58. 22.100
   libavdevice    58.  6.100 / 58.  6.100
   libavfilter     7. 43.100 /  7. 43.100
   libswscale      5.  4.100 /  5.  4.100
   libswresample   3.  4.100 /  3.  4.100
   libpostproc    55.  4.100 / 55.  4.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'short--1949-subs.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     encoder         : Lavf58.22.100
   Duration: 00:02:00.04, start: 0.000000, bitrate: 4345 kb/s
     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 
720x480 [SAR 8:9 DAR 4:3], 4148 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 
47.95 tbc (default)
     Metadata:
       handler_name    : VideoHandler
     Stream #0:1(und): Audio: ac3 (ac-3 / 0x332D6361), 48000 Hz, stereo, 
fltp, 192 kb/s (default)
     Metadata:
       handler_name    : SoundHandler
     Side data:
       audio service type: main


Thanks for any help.

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